The Supermassive Podcast - 15: Neutron Stars - with Jocelyn Bell Burnell

Episode Date: March 26, 2021

"I was tracking down every signal that it picked up, and there was one signal that I couldn't make sense of." Professor Dame Jocelyn Bell Burnell gives Izzie and Dr Becky a neutron star 101 and tells them how she discovered pulsars in the 1960s. Plus, Dr Robert Massey takes on your questions and tells us what to look out for in the spring night sky. Book Club Recommendations  Forgotten Women: The Scientists - Zing Tsjeng  Six Impossible Things - John Gribbin  The End of Everything (Astrophysically Speaking) - Katie Mack  Vera Rubin: A Life - Jacqueline and Simon Mitton Cosmos - Carl Sagan The Book Nobody Read - Owen Gingerich Don't forget to send your questions or space book club recommendations to [e-mail] or tweet @RoyalAstroSoc using #RASSupermassive. The Supermassive Podcast is a Boffin Media Production by Izzie Clarke and Richard Hollingham.

How small is the smallest neutron star, Detective? I was tracking down every signal that it picked up, and there was one signal that I couldn't make sense of. Neutron stars, famously, made from neutrons. Hello, welcome to the Supermassive Podcast from the Royal Astronomical Society, with me, Izzy Clark, and astrophysicist Dr Becky Smither. Yep, and this month we're looking at neutron stars and pulsars and we have a very special guest

yeah absolutely we've got an interview with the astrophysicist dame jocelyn bell vanell she gives us a neutron star 101 and tells us how she discovered pulsars in the 1960s i mean i know i was just incredible to talk to her like i mean she's a legend in the field right but she's also this you know just a huge role model for women in science too and i swear i got goosebumps talking to her like she's just amazing it's one of those things where we're living in that zoom life now that's like does my background look okay like what does just think? I was like, she doesn't care. She doesn't care. And we have our usual, but still very special guest, Robert Massey, the Deputy Director

of the Royal Astronomical Society. Robert, how are you doing? I'm doing well, and I don't think I'm going to compete with specialness with Justin. We could all try, but we would all fail um so we're talking about neutron stars uh this month so let's just kick off how far away is the nearest neutron star to earth do you know can it be seen sort of with human eyes yeah i mean it's a very interesting question actually there seems to be because they seem to be quite hard to measure their distance unless they're you know it's not the easiest thing and the nearest one is a few hundred light years away they all have slightly uh unmemorable catalog names this one goes by the name of rx j1856.5

3754 and appears to be about 400 i just kept going that didn't it i was expecting it to end and it just kept going exactly but it's it's about 400 light years away, and it's magnitude 25.6, which if you know anything about how bright things are in the sky, that's incredibly faint. So it's just about visible with telescopes. But, of course, they emit X-rays and radio, as you'll hear from Jocelyn later on. And we always hear that these are really dense objects,

but I often find that it's really difficult to put that into context yeah i mean the classic reference is that a teaspoon of neutron star material has a mass of about four billion tons now to put that perspective there's several ways you can think about this first of all if you had a liter or a cubic meter rather of neutron star material the mass would be way way bigger than mount everest secondly if you took that four billion tons and teaspoon and put it on earth it would do something quite destructive all the kind of huge gravitational forces binding it together would have gone and it would basically blow up a large bit of the earth so we don't want to have a teaspoon of neutron star material with us but they are insanely dense god yeah that really does just put it into perspective cheers we'll catch up

with you later in the show as well to tackle some listener questions with me. They've pulled them out the bag this week. Let's just say that. So where to begin? I mean, it's not every day that you get to Zoom the person that discovered pulsars, which are a type of neutron star. Becky and I have been speaking to Dame Jocelyn Belbonel, and she starts things off by explaining what a neutron star is and how they're

formed. Neutron star is very small as stars go. It's only about 10 miles across. It weighs the same as a typical star so it's incredibly tightly packed and they're formed when a big old star explodes at the end of its life. You can imagine the central part of the star getting kicked against in the explosion and getting compressed, shrunk down. That can give you a neutron star. So how did it get this name, neutron star? Can you talk me a little bit through that? In an atom, there's a nucleus of an atom and electrons around the outside. There is a nucleus of an atom and electrons around the outside. And in the nucleus of the atom, you find two major kinds of particles called protons and neutrons. The neutrons are neutrally charged, no charge. The protons are positive charge. And it's those uncharged neutrons that largely form a neutron star. I see. So if a neutron star is this collapsed massive star, what happens next in its life cycle? Do we actually know? Not a lot happens to be

honest. Because it's been compressed, it's also spinning more rapidly. You imagine yourself spinning on something with your arms outspread. If you pull your arms in, you spin faster. And the neutron star has been shrunk down. So it's going to spin faster naturally. And they do. They typically spin several times a second. So it sits there spinning. And if it's got a strong magnetic field, it'll be a pulsar. It will pulse away. It will gradually slow. And there'll come a time when it doesn't have enough oomph to send out this radio beam. So it's no longer detectable, but it's still there. So it becomes a dead, quiet neutron star. And you were involved, weren't you, Jocelyn, in the discovery of this special type of neutron

star pulsars, which we'll hear a little bit more about later, I'm very excited for. But you touched on this idea that they're spinning really fast. And I think one of the questions I always get asked is sort of why are they spinning so fast? And you talked about them sort of compressing and pulling inwards, but where did they get that spin from in the first place, like even as a star? It seems that every star that we can suitably scrutinise is in fact spinning, albeit rather more slowly. The sun's spinning with a period of about 28 days, for example,

although because the sun and other stars are fluid, they don't all, not all bits spin at the same rate. So it's not a solid ball spinning, it's a ball of gas spinning. And it happens, I think, largely by chance, the way the bits come together to make these stars in the first place. If they don't merge exactly head on, but so to speak, merge shoulder to shoulder, then they're going to have a spinning body. And that's very, very common in the universe. Great. So does that mean that all neutron stars are pulsars? And if so, why or why not? Do we understand? It seems that not all neutron stars are pulsars. The ones that are pulsars we know have got very strong magnetic field,

probably the key ingredient. That plus a reasonably fast rate of rotation. So how is it that pulsars are able to radiate light? How does that happen? They don't radiate light, but radio waves are related to light. So it's basically the same question. We're not really able to explain that very clearly at the moment and certainly not very simply. It's a highly complicated process involving something that's spinning very rapidly and something that has a very strong magnetic field.

something that's spinning very rapidly and something that has a very strong magnetic field and a magnetic field that's probably not orientated along the spin axis. So if the spin axis is vertical, the magnetic field is orientated at an angle to it. And so it cones around and it's something to do with that coning around as well as the high speed of rotation and the strength of the magnetic field and quite a lot of hand waving as well so so why study what are often called these cosmic lighthouses because of that spin you know what can they tell us they can tell us a huge amount because they're one of the places where there are really extremes in the universe. There's extreme density, not quite up to black hole density, but getting there, they're the next best thing to black holes. Extreme magnetic fields, extreme electric fields, high speeds of rotation, high density, everything horrible thrown in at once. I like that. And have you

been involved, Jocelyn, sort of recently with, I mean, with learning so much more now from gravitational waves as well, aren't we? When we have mergers of neutron stars or mergers of neutron stars with black holes, are we learning more from that side of things, seeing these neutron stars in a way that we've never seen them before? We've been looking out for mergers of neutron stars and the gravitational wave people were, that was what they were expecting to see first. And then they happened to stumble over black hole mergers with black hole masses that we didn't know existed. And the majority of things that the gravitational wave detectors pick up are still the mergers of black holes, 50 solar masses, 30 solar masses, that kind of thing. So there have been very, very few neutron star mergers

detected so far. I guess we'll just have to keep our fingers crossed then and hope that we spot some more soon so we can learn some more. Yes. And is there anything, you know, in the future of this field that you're really excited by or you'd like to see happen? Well, I think if you'd asked me a few years ago, I'd say I wanted to see gravitational waves detected. That was a huge achievement, partly fuelled by the fact that there were these black holes we didn't know existed, which kind of stood up and waved at us. I'm fascinated by what gravitational wave astronomy is revealing, and there's going to be lots more coming along. We're still very near the beginning of that whole

new field. Dame Jocelyn Belbonnell, now professor at the University of Oxford. Becky, I literally wanted the ground to swallow me up at that moment where she says, oh, they don't radiate light in response to my question. I was like, oh my God god why did I just ask that what have I done I think it was totally fine like I knew what she meant like radio light it is a form of light right it's on the electromagnetic spectrum but they don't radiate visible light I just think it was the way you phrased it and I when she said that and you I just saw you like react like you just twitched like oh god that was the worst moment of my life you know like when someone you're just like fascinated by her life and her work you're like god i'm an idiot what have i done but we are mixing things up a bit this month and we've got

a few questions from our listeners for you becky and for you robert so becky can you start us off with this one from david david cinder, how can a neutron star have a magnetic field if by definition it's made entirely of neutral particles? Yeah, just hitting us with the hard questions today, David. Like magnetic fields are an astronomer's kryptonite. What are you doing to me? But yes, like, so as David says, and he alludes to like,

to get a magnetic field, you need moving charges right so inside earth we talked about this before on the podcast right we have a molten core of iron and because that gets you know heated you have convection stops moving and you set up a magnetic field because you've got free moving charge particles and that generates a magnetic field and the same is true in the sun in the plasma and everything but as david says neutron stars famously made from neutrons neutral particles and of course it sort of plays into the fact that you know neutron stars they are very exotic we don't a hundred percent understand them but our understanding at the minute is that it's not as simple as neutron stars being just like this big crystal of stars

made of neutrons right it's got like layers to it right like an onion and organ has layers onions have layers neutron stars have layers right so you have um sort of a layer at the very top that's electrons then you have a layer of the heavier elements like iron and things like that with again with electrons mixed in then you have sort of transition regions of a mix of all that stuff until you get to the core where we think you do have neutrons in a superfluid but it's still not pure neutrons we think there is some sort of impurities in there of charged particles and they might be electrons but they might be more exotic particles as well sort of from the standard model or whatever they might be they'll be charged and with that slight impurity even

spinning at the incredible speeds that neutron stars do to make pulsar 10 to 70 of the speed of right right yeah even if you have this minute amount of impurity of charged particles they're still going to be moving at incredible rates and you're going to get these huge magnetic fields that neutron stars are known for so even though though we're not 100% sure on exactly what the interior of a neutron star is, because they're so exotic, you know, our best guess is that this is, you know, this impurity is what could explain magnetic fields. Amazing. Thanks, Becky. And Robert, Lanky Brit Phil wants to know, how small is the smallest neutron star detected?

Well, again, looking this up, you come up with some extraordinary, more unmemorable catalogue names. So it appears to be one by the name of CXOU, and then a longer name which refers to its position in the sky. And that one could be as small as 1.2 kilometres across. Having said that, I looked up, tried to look at various papers around it, and there's some uncertainty around that, as is the measurement of its distance again. What you can say is that all neutron stars are really small they're much smaller than other types of stars i mean to compare it with a white dwarf which is itself you know fairly exotic even if there are a lot of them uh the smallest white dwarf is about a thousand times as big so the size of a hill i think is about the smallest neutron star size

you can imagine up to say the size of a small town so i love that very very small the size of a hill next time i go walking like in the lake district i'm gonna be like exactly the size of a neutron star and becky as our black hole queen black hole queen i like that i'm putting that on my cv now thank you for this astrophysicist black hole queen well Stas has a question for you Stas Kropenia asks when two black holes merge we can detect gravitational waves but would the merging of two small black holes or two neutron stars result in gravitational waves essentially what's the smallest object that

can cause gravitational waves yes so we've detected neutron star black hole mergers neutron star neutron star mergers as well in gravitational waves the really famous one was the first neutron star neutron star merger we detected which is gw 1708 17 burned in my brain that number now and that was we're hearing that these names are just so catchy on but yeah that was the first neutron star neutron star merger we detected and it was really exciting because because it's neutron stars not black holes we got light from it so x-ray optical uv gamma ray everything you know across the spectrum and it was sort of the worst kept secret in astronomy at the time as well but it was i mean it was massive because it allowed us to you know really study them and also like rewrite the theory of how we think a

lot of heavy elements form as well like we realized that actually a lot of the heaviest elements are actually forming in these neutron star neutron star mergers which was really exciting in terms of what can produce gravitational waves technically anything that is accelerating through space can produce gravitational waves so for example the earth orbiting the sun it's not a perfect circular orbit if it was it would always be going at the same speed but it's an ever so slight ellipse which means that the sort of narrowest point of the ellipse sort of like if you imagine it a bit like an egg shape it'd be sort of you know the top of the egg right it does accelerate slightly and so technically it will give out gravitational waves,

but because the Earth isn't very heavy, it's not very massive, there'll be very, very small gravitational waves. Like it won't be very energetic. Compare that though to two black holes orbiting each other or two neutron stars, really dense, very massive. They're going to have a massive effect on the space around them when they accelerate.

So for example, when they're orbiting each other, again, they're not on perfect ellipses. So you can imagine this sort of point where they all of a sudden accelerate and give off more gravitational waves, and those will be much more energetic. So technically, you're only limited by the detection limits of your gravitational wave detector, right? So whatever the smallest, you know, change in the distance is that these gravitational wave detectors can measure and this is how they do it they say okay what's the distance between these two mirrors they measure it with lasers and if that changes it's a gravitational wave passing through and i think ligo at the minute it's um the smallest thing it can measure is

a change of one ten thousandth the width of a proton which is crazy that they can get that accurate it's ridiculous and i looked it up i don't know if that's sort of like the limit of what they've detected so far because obviously it depends on what's actually merging in the milky way yeah surrounding universe and everything but the smallest thing they've detected so far is a neutron star neutron star merger where both neutron stars were around about one and a half times the mass of the sun okay but obviously like that's ligo it could change if we make something that's perhaps more sensitive or sensitive to like these different frequencies or energies of the radiation of the gravitational waves that are given off yeah so in the future you know if our

detectors get much more sensitive then we could detect a whole range of events essentially there don't have to be these huge energetic collisions yeah and robert now i love this question from harry rumor and he asks in future space exploration could we use pulsars as beacons i mean that really takes us back to this idea of these cosmic lighthouses i love it yeah i mean this is you know let's face it you wouldn't intuitively ask this question really would you but it turns out that um as long ago as a decade ago some german scientists verna becker from the max black institute for extraterrestrial physics in garking uh he presented work on this at a conference that we ran in manchester and back back in 2012 And the conclusion they reached was that, yes,

they would actually be really good navigational devices because pulsar times are so accurate. You can use them. You can look for delays in those times and you can navigate to within a few kilometers, even if you're somewhere between the stars. So this has got quite a history in the sense that the Voyager probes included on their golden disks,

they included a map of the solar that the Voyager probes included on their golden disks, they included a map of the solar system in relation to pulsars. And what the German group and then NASA more recently have done is to work out that you can actually use them to navigate. So you could find your way around the solar system. And if hypothetically you're traveling between the stars, you could do that too, to a really high degree of accuracy. And the NASA team, they used an experiment on the International Space Station to confirm this technique and to work out that it was actually practical. So I think it's really intriguing is the idea that you've got this kind of inbuilt natural interstellar GPS system just waiting to be used. Do you know what accuracy it was, Robert? Do you remember?

Because I read a paper the other day that was talking about doing it with stars instead of pulsars, and it wasn't very accurate. They claim it's a few kilometers so that's amazing so i remember it was literally last week or something there was a paper that came on the archive that caught my eye and it was um from someone at max plank and they'd been thinking about could you do it in terms of maps of our positions of stars and they were saying our knowledge of the exact positions of stars on the sky would have to improve by something like a thousand times otherwise we could only pinpoint where we were in interstellar space to an accuracy of three times the distance between the earth and the sun so the fact that you can use pulsars to do it within a few kilometers is like why are we bothered about like astrometry and trying to

figure out the exact position of stars like we should just use pulsars and it is good to know should we happen to find ourselves lost in the outer solar system or between the stars you know sure as long as i've got a piece of paper with me i'll yeah triangulate my position no problem well thanks for answering those questions. And if you're listening and you have a question that you want us to take on, then you can get in touch. You can email podcast at ras.ac.uk or tweet at Royal Astro Sock and we'll take a look. This is the Supermassive podcast from the Royal Astronomical Society with me, astrophysicist Dr. Becky Smethurst and with science journalist Izzy Clark.

Now, I know we're a month late, but as promised, it's Science Book Club time. So did anyone remember the biscuits? No, but I think I've eaten enough in lockdown as it is. I haven't eaten enough personally. So we've all bought something that we want to talk about. personally so we've all bought something that we want to talk about um I'm going to go for the option of good books that you can dip in and out of depending on how much science you want in your life so one book that I'm reading at the moment is called Forgotten Women the Scientist by Xing Xing and it's just brilliant over a couple of pages it tells the story of some of the women in science that we just don't hear enough about so Cecilia Penga Poschkin's in there we talked about her last month just yesterday I was reading about Annie Scott

Dill Maunder who took some really incredible pictures of the sun's corona in the late 1800s early 1900s and if I can squeeze in another very small book which is literally 100 pages long a bit different bit of quantum physics for. It's called Six Impossible Things by John Gribbin. And it's just a look into the puzzling world of quantum physics and six ways that we attempt to explain or interpret what's going on in the quantum world. So again, that's just a nice, I say light reading, it's quite complex, but it's a short one. Nice. I like the sound of that Forgotten forgotten women one that sounds like a really good like coffee table book when we can have people in our houses again I'll like surreptitiously like leave it there while I go make them like a cup

of tea and then the next minute they've learned something about exactly I mean they're stories that are just told so well and so simply and it's it is it's perfect for that just oh I've got a few minutes on the safe I'll just have a have a read of this it's it is it's perfect for that just oh I've got a few minutes on the safe I'll just have a have a read of this it's great I love it Becky what what are you reading nice yeah yeah so I have just finished a book I mentioned before actually I mentioned was it last week month or month before I'm not sure uh Katie Mack's book the end of everything astrophysically speaking and I've just finished it and oh my it was so so good like I know it's not technically written for

me because Katie Mack is a cosmologist and she's explaining you know here's how the universe could end and sort of the heat death of the universe and it's stuff we've covered before but Katie is just such a good writer that it's just so engaging and it was so so enjoyable so there's a bit of a bigger dive like a bigger book if you want something a bit more meaty and then I'd definitely recommend that my next on my list which I'm very excited about is Vera Rubin A Life which has been written by Jacqueline and Simon Mitton. Yeah I've got this too. And that's going to be sort of the first biography of Vera Rubin so I'm really excited to to dive into that. I've sort of read the introduction so far and it comes out I think on the 26th of March. It's coming out very soon for

the sort of the public so I'm sort of diving in a bit early but um i'm just yeah i'm really excited to read it because i think that kind of full biography of vera rubin like you hear so many different things so i'm really excited i'll let you know i'll let you know how it goes and for if anyone hasn't heard of vera rubin like who who is she just tell us yeah so vera rubin was um an astronomer in the 60s and um every sort of science result she turned her head to, she was like, I'll try and do something less controversial now. And then she ends up sort of finding the first observational evidence for dark matter. So she was very influential. Yeah, throughout the 60s, 70s, and onwards throughout the rest of her life as well. Sort of like Jocelyn Bell Burnell herself, you know, very interesting science, but then also such a huge role model as well for women in science. She was such a pioneer. Amazing.

And Robert, what have you been reading? Well, I'm reading definitely a weighty book, Neutron Stars, which is by actually an ex-BBC journalist, Katya Moskovich. And she's now doing a lot of, she's a science journalist, essentially. But I read it and I thought, actually, this is almost like a good text for graduate students,

not because it's super hard, but because it covers so much in such detail. So you could read through it and you could think, okay, there's a lot about neutron stars in this that I simply had no idea about. And she breaks down all the differences between the different types of neutron stars, pulsars and magnetars and so on. So, you know, thinking of the theme of today's program, if you want to find out more about neutron stars, then I definitely recommend this book.

She also covers their use in astronomical tools and navigational tools as well, you know, not just for finding your way around the cosmos, but also for testing Einstein's theories, gravitational waves, and all of those things. So you want to know more about neutron stars. I don't think you could do a lot better than this it's a great starting point i think i'm going to add that to my list my ever ever growing list to read and we've also had some

great recommendations on twitter too from you guys so sean chesman recommended cosmos by car sagan obviously one of the classics i guess we couldn't have done astro book club without it and andy sawyer's had quite a few too. The book Nobody Read by Owen Gingrich, which is apparently the story of Copernicus' scientific work on the revolutions of the heavenly spheres. I've never read that. Have any of you read that one? No.

Oh, those are some good ones. Well, one to add to the list. Yep. It is a classic. We have a copy of Copernicus' original work in the RAS library. We'll just read the original copy. Absolutely. When we open up again, just come and spend a few days reading that.

Absolutely. And that's it for this month's book club. We'll list all of those books in the episode's description, so don't worry about scribbling them down. And next time, I promise, there will be biscuits. All right. Let's get back to this month's topic. We've explored the science behind pulsars but how and when were they first discovered? So someone in science myself at sort

of the beginning of my career I was very interested to talk to Jocelyn Belbonnell about how she even discovered pulsars and it turns out it starts with her PhD in 1965. So I turn up in Cambridge and at that time there were very, very few women. There were only three colleges for women. And it was populated by young men who were supremely confident in their abilities, confident of their right to be there. And I kind of quailed I thought oh my god they've made a mistake they're going to discover their mistake they're going to throw me out we now have a name for this and for those of us who work in Oxford or Cambridge and other

prestigious places we know to look out for this it's's called imposter syndrome. And in a bad case, the student will take themselves way back home really before term or the year has started. But I'd had a struggle to get there, so I wasn't taking myself off home. I decided to work my very hardest so that when they threw me out, I would feel I'd done my best and I just wasn't bright enough. me out. I would feel I'd done my best and I just wasn't bright enough. So being a PhD student in this brilliant place, I decided I'd work my very hardest to do my very best. And I was being incredibly thorough. And I had a project to find quasars, which are some of the most distant things in the universe. Barely recently discovered by the radio astronomers, a really hot topic, brilliant topic for a thesis. But I had to spend the first two years building the equipment, and then in the third year actually started taking data. And because I was being very thorough, making sure the equipment was working properly, making sure I understood it, I was tracking down every signal that it picked up.

And there was one signal that I couldn't make sense of. Went around the sky with the stars, so it had to be something up there in the sky, but I couldn't make sense of it. And discussions with my supervisor decided on a special observation to get a magnified version of the data. And it turned out to be a string of pulses, one and a third seconds apart. And that was the first pulsar, kind of thing that had not been dreamt of, that we didn't know this telescope would detect. But in fact, the telescope was reasonably well equipped to detect that kind of signal. It just required somebody who scrutinized the data extremely carefully to pick up what initially was just one of these sources. Quite hard to explain something that pulses with a period of one and a third seconds. It has to be small. And because it kept the period very constant,

it has to be big, which means it's got large energy reserves. So it's not getting tired. So it's keeping pulsing at the same rate. And to begin with, we couldn't make sense of it's big and it's small. But finally, this idea that they might be neutron stars gradually grew. And things got a lot better when I found a second one you know it's not the grad student's fault it's not phony signal and I found a third and a fourth as well so clearly I'd stumbled over a new class of something. How did it feel then in those instances of you know the first one you said there isn't the grad student's fault is that something you felt at the beginning that it was almost you were raising something that might not be real but then by the third and fourth did

you feel sort of very confident with you know because I think people imagine these sort of discoveries as eureka moments but that makes it sound like it was sort of a very almost drawn out process before sort of this discovery really of what they were came to light. Yeah, you're right. Discovery process is rarely instantaneous. It is a process and there are milestones on the route. So finding the first one was one. Getting a colleague with another radio telescope and another receiver to also pick it up was another milestone because it showed it wasn't some funny flaw in our equipment. Finding a second one was a huge relief. It also meant we could publish the first one.

So, Justin, how were you actually able to monitor these signals? Because, you know, I think we take it for granted with the amount of technology that we have. So how were you keeping track of all of this and, you know, trying to put this puzzle together? Yeah, well, the equipment was pretty primitive in the 1960s. The radio telescope was largely made with wire. If you imagine that old style of television aerial that was in an H shape that we clamped to our chimneys, you take a couple of thousand of those and wire them up together. You've got some impression of what the telescope itself is like. At that time, the University of Cambridge had a computer, one computer. It had memory comparable to a laptop today, and that served the whole university.

So actually, very few people had time on it, and we didn't. So our data came out on rolls and rolls and rolls of paper chart. And I had kilometers of this paper chart. I think it was five kilometers in total. Wow, five kilometers of paper. Your story seems almost very similar to people I think from the movie Contact, right, that Carl Sagan wrote the book and the film

with Jodie Foster. And it's sort of fun to compare the kilometres worth of paper you had compared to her listening to pulsars that they went for in the film, I guess. Some nice throwaway points in the film. Oh, it's only a pulsar. Yes, I noticed that when i watched it

but you always like cringed at that so you discovered these pulses but how did you make the deduction that they were neutron stars we didn't initially we had two possible models one was the spinning neutron star actually my, my supervisor, Tony, favoured it being a slightly bigger kind of star called a white dwarf that was oscillating and sending shocks up through its atmosphere. And I remember well the colloquium he gave just before the first paper was published. And Fred Hoyle sat in the front row and Tony went through what we'd found and presented his theory that it was probably a white dwarf oscillating. And at the end of his talk, Fred Hoyle was the first person to speak. And I'll try and do Fred's Yorkshire accent. This is the first I've heard of these things.

I don't think it's a white dwarf. I think it's a neutron star. And Fred, starting from cold in 40 minutes, has hit the right explanation. He was a brilliant astrophysicist, that man. Wow. And Justin, you famously didn't get the Nobel Prize for this. That went to your supervisor, Anthony Hewish, along with Martin Ryle do you think something like that would still happen today it could well happen today but I think it's less likely to happen to be honest grad students rarely get Nobel Prizes it's normally senior academics that get Nobel Prizes just occasionally they do something different. Since when Joe Taylor and Russell Hulse got the Physics Nobel Prize for the discovery of the binary pulsar, and the confirmation that there

was gravitational radiation, they awarded it to both of them. But they were much closer in age to begin with, and times were changing by the time they awarded that Nobel Prize. Another thing that stands out to me, Jocelyn, when I sort of read the history of what you've been involved in is just the amount of work you've done for women and underrepresented groups in science as well. I'd like to thank you for that, especially for all the support you do. Does that stand out as something that you're presumably very proud of as well? Yes. It's been quite hard, hard to be honest being a woman in science for instance i can remember when i became pregnant going to my head of department and saying

what maternity leave am i entitled to and he said maternity leave never heard of it university did not have maternity leave yes Yes, I think science still tends to be, the majority tend to be white males. I do believe that diversity improves the strength of the subject. And indeed, there's been research by management consultants like McKinsey's, which shows that a diverse workforce is stronger and more flexible and more successful. So I've been pushing for most of my life for better opportunities for women in science. That's now been extended beyond women to all minority groups. And Justin, finally, you have done so much in your career. So is there a piece of advice that you have for someone that's at the beginning of of theirs that would help keep them on that journey I think perhaps one of the most important things is to find a topic that you're interested in and then hang in there it will be difficult

it will be uphill you will go backwards but hang in there and you'll win through. And because of your persistence, you'll do really good work. Some excellent advice. That was Dame Jocelyn Belbenau. Becky, do you think Jocelyn would mind if we just added her to our best friend list along with astronaut Samantha Cristoforetti? I think it's a pretty good company. I think she would be fine with that yeah I mean it helps that I work in the same building as her right like in non-covid times anyway like I think I remember when I started my PhD like just being so overawed by the idea that I could just nip up to JBB's

office you know just knock on the door with that friend I remember I like to call her I interviewed her in 2017 and I interviewed her in the Jocelyn Bell Burnell room in Cambridge I was like have you ever been in a room named after yourself she's like no I don't think I have um also did did you see that Samantha Cristoforetti has recently uh it was recently announced that she's going to be returning to the ISS next next spring spring 2022 so that's exciting no I didn't see that that's so exciting maybe we can interview her again but when she's like on the iss that would be amazing and if you have no clue what we're talking about uh then listen to our episode with astronaut smother christopher reti

it's called humans in space and it will make much more sense but we fangirl a lot as we tend to do in this entire series um but you know just hearing jocelyn talk it just makes me want to go out and stargaze and just explore our universe albeit from my garden but oh well um so robert what should we be looking for this month where can i begin yeah i mean i mean from our gardens i guess um look this is the spring star season so all those beautiful winter constellations are now moving out of view but you do have you know nice things to see um this time of year you get ursa major and the plow very high in the sky and you can find other things that's a really nice signpost you can use the the tail of the bear it's got a ridiculously long tail for a bear

um the curve you and there's a whole a cheesier uh mnemonic for this where you are not a mnemonic cheesy uh rhyme where you follow the arc to down to the bright star arcturus and you speed on to spica in virgo and the that whole region of sky has relatively few bright stars in it but it does have a lot of galaxies so if you have a pair of binoculars and you're lucky enough to have a darkish sky spring is really galaxy hunting season they mostly look like smudges but you can move a pair of binoculars around you'll see a lot of them and it's just intriguing to think that you're looking out into the deep universe now if you're into astrophotography you've also got another opportunity which is that Mars will be near the open cluster Messier 35 in Gemini

on the 26th and 27th of April so we'd really like to see any pictures you get of those I think it'll be a nice sight with binoculars and not bad with the eye and if you've got a camera on with a long lens on a tripod you should be able to get some great images too and I should also mention that there's a new well not, not a new star, although that was how the name arose, but a nova in Cassiopeia that was discovered last week. Now, it's not visible to the eye, but it is visible with a pair of binoculars. And if you've got the equipment and you know how to use the finder charts, Cassiopeia is a famous W-shaped constellation. It's best viewed pretty much either at sunset or before dawn and you'll see this new bright star

if you know where to look. So it's not spectacularly bright or anything like that, but it is just an intriguing thing to see. I can see already picture the astrophotographers getting out there and my Instagram is going to be flooded with all of these amazing images that I will never take. Yeah, someone said to me the other day,

like, should we compare like, you know, amateur astronomy images with like professional astrophysics images and i was like no because we would always lose unless they're taken by the whole school like ours is so oddly scientific it's just like pixel blurs i mean yeah how do you compete with planetary photographers in the 2020s i mean they're insanely detailed pictures i mean they're just yeah you see yeah i would never have dreamt that you could image the moons of jupiter in detail with amateur galileo would be so jealous of me it seems utterly impossible it's amazing i mean speaking of uh like amateur imaging i mean there was a lot of complete novices that captured

something they didn't expect this month as well right on all these um doorbell cams people were discovering this meteorite that fell this fireball yeah we in the uk we've had a rare example of a meteorite a recoverable meteorite dropping over gloucestershire so there was a big fireball scene on the 28th of february essentially as far as i can see it wasn't necessarily seen by many people but a lot of the cams or at least security cameras picked it up which seems to be the way these things are found these days and through triangulating all that footage they were able to deduce that the debris field where the rock broke up and landed on earth was near Gloucestershire or in Gloucestershire near the town the village of Winchcombe And so teams from the UK Fireball Alliance, which sounds like a great collaboration.

Which is great. Went out and found this. And for example, a lump appeared on someone's drive and the family described hearing a thud in the night and looking out in the morning and seeing this. And they thought, and their response was, who's been chucking coal on our driveway? And so the team went out and totally saw the reports.

And then the team came and picked it up. And they also then found them in various fields in the area as well. My colleague, Anya O'Brien, she was on this team and she had to keep it very, very quiet. And she said, she only does a day or so a week with us. And she said, well, I won't be able to do any work with you next week as much because I'm analysing this carbonaceous chronotripe, this amazing discovery. And I thought, that's a fair excuse. Finishing your PhD doing this is a really nice thing to be doing.

It was amazing though, wasn't it? Because it's the first meteor to have landed on UK soil since 1991, which is crazy ridiculous. But then literally the other day, there was then this sonic boom over the Bristol Tower. Another one. Another one. It never rains, but it pours.

Yeah, and it was cloudy. Yeah. And it was cloudy in the UK. So there's nobody seems to have seen it, but were people out for walks hearing a sonic boom and thought it was a fighter aircraft or something like that? The NAD said no. But there's footage from France of it low in the northern sky

because they didn't have clouds and they could see it there. So now the hunt is on for that. If debris comes down to Earth, which seems likely to have done, because of the sonic beams, it means it's slowed down and so on, and that's when the rocks drop down. It'd be in the region of either Dorset or Somerset or Devon, so they are asking people to have a look out as well. Well, I think that's it for this month.

Next month we'll be finding out what's lurking in the outer edges of our solar system with the Kuiper Belt. Yeah, I'm really, really excited for that one. I love the Kuiper Belt. So make sure you send us your questions. It's at Royal Astro Sock on Twitter, or you can email podcast at ras.ac.uk and we will try and cover them in that episode.

But until then, happy stargazing.