Instant Genius - Dr Becky Smethurst: How do you actually find a black hole?

Episode Date: January 9, 2020

By day Dr Becky, is an astrophysicist, unravelling the mysteries of supermassive black holes, but by night entertains science buffs like us on her YouTube channel. In this week's episode of the Science Focus Podcast she explains how to find a black hole (and why they’re actually incredibly bright), what an astrophysicist does all day, and why flooding YouTube with scientists is the best way to counteract disinformation and bogus theories. Her book Space: 10 Things You Should Know (£9.99, Orion), is out now and you can read an extract from it here. Subscribe to the Science Focus Podcast on these services: Acast, iTunes, Stitcher, RSS, Overcast Let us know what you think of the episode with a review or a comment wherever you listen to your podcasts. Listen to more episodes of the Science Focus Podcast: Kathryn D. Sullivan: What is it really like to walk in space? Monica Grady: What is the future of space science? Mark McCaughrean: How do you launch a successful space mission? Kevin Fong: Why is the Moon landing still relevant 50 years on? Bruce Banerdt: What NASA's InSight will tell us about Mars Natalie Starkey" What asteroids can tell us about our Solar System Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. But yeah, I mean people often ask me, and I talk about this in my book as well, whether that scale of the universe is scary, you know, and it can make a lot of people feel quite anxious in the way that it sort of, of not belittles human endeavors, but, you know, it can make them feel very small. And like, I don't feel like that when I think about the scale. I understand why people do. But instead I say

to people, well, instead of thinking like that, think about how it means there's like infinite possibilities. There's like infinite stuff you could do or you could go or you could be. And that, I think, is really exciting. You're listening to the Science Focus podcast. from the BBC Science Focus magazine team. With the UK's best-selling science and technology monthly, available in print and in several digital formats throughout the world. Find out more at ScienceFocus.com or look out for us in your app store.

Hello, and a belated happy new year to you all. I'm Alexander McNamara, online editor of BBC Science Focus. This week I chat to Dr. Becky, who by day is an astrophysicist unraveling the mysteries of supermassive black holes and by night entertained science buffs like you and I on a YouTube channel. She explains how to find a black hole and why they're actually incredibly bright, what an astrophysicist does by day, and why flooding YouTube with scientists is the best way to counteract disinformation and bogus theories.

My name is Dr. Becky Smethyst, and I am an astrophysicist at the University of Oxford. And what is it that you're, you know, what's your specialism? So my research focuses on supermassive black holes. These black holes that we think are anywhere from a million times the mass of the sun up to like a billion. in times the mass of the sun. And I like to look at how they can affect the galaxies that they live in the very centre of. Like, does the energy that goes into feeding the black hole and then can get output from sort of the surrounding area as well somehow affects the galaxy it lives in, either by disrupting the shape of it or stopping stars from forming within it as well. So really cool area

of science that I absolutely love. That's, it's pretty big stuff for he's thinking about black holes. So how is it, like you actually are able to go, okay, how do you find a black hole to start with? And then how do you go like, how is this affecting everything? Yeah. So finding the kind of black holes that I look at, the supermassive variety, it took over the past sort of 50 years for us to get to the point where we have a theory that is accepted

that there is a super massive black hole in the center of every galaxy. So the best place to look for one is in the center of a galaxy. And the giveaway for finding them in the centers of galaxies is actually that they're incredibly bright, which is a very strange thing to say about a black hole. However, what we think happens is that the material that's falling into the black hole, which ends up forming like a disk as it spirals around it. So the same way that, you know, making a pizza, you would, throw a ball of pizza dough above your head and you'd start it spinning and it would flatten out

into a nice pizza-shaped disc. The same thing we think happens to material as it falls into the black hole. It comes in as a blob, but because it starts spiraling and spinning around the black hole, it flattens out. And then in that disc, as it's spiraling so fast around this huge object, all that material starts to heat up and it starts to glow and, yes, the infrared, but also things like x-rays as well, and also optical light that we can see. And so we've been calling these objects quasars for a long time. And it only took sort of the past sort of 30, 40 years for us to realize that these quasars are actually powered by super massive black holes. And are those black holes specifically that says, why are they, if, you know, if we can see all of this stuff around it, why can't

we see a black hole? Yeah, we can't see a black hole because when matter has, fallen into it, it has to be traveling faster than the speed of light to escape the gravitational pull again. And one of the most basic laws of physics is that nothing can travel faster than the speed of light. And so nothing can escape from a black hole, whether it be matter or whether it be light. Therefore, we can't see anything in it because not even light can escape. And so you end up within a region of space which has so much stuff in it. It's so densely compacted matter. It's just that we're not able to see that it's there.

You end up sort of referring to it as like a shadow on the rest of the stuff we can see. So that sort of makes me wonder why. So this is probably going back to a sort of basic physics level. But why is it that all of this matter that's completely. impacted, what is the effect that that's having with light and what's making it nothing, you know, why is no light able to sort of escape it? Yeah. So if we think about the earth as a start off, you know, you can throw a ball above your

head or you can try and jump off the surface of the earth, but you're not going to make it off the surface of the earth because we physically don't have enough energy to power ourselves off the surface. Gravity is always going to win that fight and pull us back down. we can, however, launch rockets off the surface of the Earth. And that is because we've given them enough energy to counteract gravity pulling down on us. And so you can work out the speed that you need to reach in order to escape the Earth's gravity. And that speed for the Earth is, I think, 11 kilometers per second, which is quite large, even for the Earth.

And so if you then think of a much heavier object where you've probably put a million times the mass of the sun inside, say, Earth's orbit. So inside a very small region of the solar system, you've got a lot of mass in one space. And so all of a sudden you've not just got Earth you have to escape from. You have all of this stuff pulling you back down and all the gravity constantly pulling you back down. And so you get to the point where you work out what we call this escape velocity that we have on Earth, you know, that we can fire rockets up to escape Earth's gravity. The escape velocity for a black hole is bigger than 300 million meters per second. Right.

And that is the speed that light travels at. And nothing can travel faster than that speed. And therefore, you can never get back out of a black hole again. And that's why they appear black. Yeah, exactly. they appear black because light is not given off by the black hole. It's not reflected by the black hole because it can't get back to us. It's essentially absorbed by the black hole. Sounds like quite an unpleasant place to be. Yeah, a little bit. One of my favorite favorite facts

about black holes is that if you were to fall into a black hole, say, feet first, right? And you were just sort of traveling towards it feet first. The gradient of how strong gravity would be, would mean that the gravity was so much stronger at your feet than at your head that you get stretched out like spaghetti. And it's called spaghettiification, and it's possibly my favorite word ever in the history of science, is spaghettiification, the fact that that is a real thing. So, like, hypothetically in that sort of situation,

and this is probably more of a biology thing, but would, you know, with relativity and everything like that, would you feel like you're stretched out, or would your organs be stretched out the same? time, I don't know. I don't think you'd have enough time to be able to register the feeling. I think before you'd blink, you'd just be one long string of atoms running from the black hole upwards. So, yeah, I don't think you'd have much awareness of what was actually going on if you were that close to a black hole. So, you know, as you say, like the black hole is this huge,

densely packeded collection of matter. Do we know what that matter actually is? No, and that's the thing. You know, people are. always ask, well, what does the inside of a black hole looks like? We don't know still, to be honest. So what can happen is that instead of it, let me start this again, so what we do know what matter is like is in what we call a neutron star. So a neutron star is kind of like the precursor to a black hole, essentially. So black holes can form when stars go supernova and run out of fuel and die and they collapse down in on themselves. If they've got enough mass, they become a black hole. If not, they form what's called a neutron star, which is essentially neutrons,

i.e., you know, little subatomic particles, you know, you've got your protons, neutrons, and electrons that make atoms. Essentially what a neutron star is, is just neutrons as tightly packed as they can go. Like, you've squished all of the space out of an atom and you've just been left with neutrons. And then you've arrayed them in like a perfect crystal so that they like perfectly tessellate everywhere. That is like the densest form of matter that we understand and that we can like explain with our theories, you know, with a mathematical equation. We have no idea what happens when two of these neutron stars say merge and make a black hole.

What happens to those beautifully densely packed neutrons? We don't know. We essentially all we know is that it becomes a black hole and the mass. matter within it is the densest way that matter can be, we just don't know what it is. How would you, I mean, obviously this is probably, you know, already being questioned in astrophysics and people who study black holes. But how would we go about trying to work out what's in there? And also, what sort of is the, you know, kind of in a way, what's the benefit of knowing? That's the thing. I don't think we have any way of knowing, apart from sort of

theorizing. It's not something we could ever observe. So obviously the way science works is that you can come up with a theory and you come up with ways of testing that theory. So you might come up with a question that would falsify or verify the theory. And to do that, you would then go observe something. The problem is we're just not really any way of observing a black hole because we can't see anything. The only way that we might have a little bit of hope is from gravitational waves. So this is this new way that we're now observing the universe. So you can imagine if two black holes were to merge or even two neutron stars that I was just talking about were to merge,

that's a really catastrophic event, right? And what we think happens is that the gravity in those events is so strong as they come together that they essentially send ripples out into space that stretch and squash space a little bit because of the sort of echo of this really strong event of gravity that happened. And we can detect those on Earth, essentially, as like the squishing and squashing of space from a very precisely measured distance.

And so from that, we've been able to work out what happens in the merger of these systems. And so that's the only way we really have of observing them. But again, you're observing what sort of gets propagated outwards rather than what's in the center or in the middle of the black hole. So it's a very difficult question to answer, and it might be one that we might have to just sort of hold our hands up and say, we're never going to know this, and that's okay. But we'll keep on looking for more accurate ways to, you know,

these gravitational ways, we'll keep on studying them and seeing what they can tell us. Yeah, definitely. So we have about three or four detectors on Earth now looking for these, but the future plan is also to build a detector in space, which will be much more sensitive as well. It's a bit difficult to detect these squishing and squashing waves in space that pass through the earth because, you know, a lorry drives over overhead and all of a sudden your ground is shaking. You know, there's earthquakes.

So there's lots of stuff on Earth that you have to mitigate for that make it very difficult. But in space, we'll be away from all that. So people are very excited about that experiment. It's going to be called the LESA experiment to detect gravitational waves. Thinking about experiments like Lisa and then also going back to like the black holes that we were thinking about. So obviously we've had, I remember when the gravitational waves were discovered, it was a couple of years ago now. And it was, you know, it was big fanfare and it was big, this is a really exciting discovery. And then also the picture of the black hole when that came out earlier this year.

They were really cool. But I guess, you know, in the world of science and when you're studying it, these are just great things. But for people who don't know so much about them, a lot of the time they'll be asking, you know, why is this important? What is this, why is this picture or what is this telling us? Is that something that you wanted to sort of help communicate with your YouTube channel? Yes, definitely. I set up my YouTube channel essentially to be your friendly neighborhood astrophysicist, essentially that you could ask any question too,

including why we bother really with observing the universe and space exploration and everything. I mean, to me, you know, curiosity's sake is probably the best argument that makes sense most to me. like humans will always be curious. It's why Columbus got in his ship and traveled over to, you know, see if there was any land past west of Europe, that kind of thing. But it's also the unforeseen benefits of, you know, this kind of investigation of the universe. So for example, you mentioned the image of the Black Hall they managed to take that was released earlier this year. Incredible, incredible, achievement to be able to image that shadow of a black hole on that material glowing that's spiraling around it. And there was a lot of people who said, well, why bother? Like, why have we

even, why do we even care to take an image of a black hole, especially because it's taken, you know, so many millions or billions of pounds. And also it's taken years worth of computing power to do this as well. But to take that image, they had to pretty much almost invent a whole new way of analyzing the imaging data they had and then also this new algorithm to amalgamate all those images as well. And the unforeseen benefits of almost having to invent that algorithm, like we have no idea now where they're going to go. But if you look back to, you know, previous experiments in astronomy that have pushed forward and said, okay, we need to see this. So we need this new instrument or we need this new way of analyzing the data. And then a couple of years down the

line, that same data technique is being applied in medical imaging, for example, or the detectors that have been invented to see deeper and further in the universe are being implied in that. Or one of my favorite examples is the algorithm that was used or invented to figure out where astronomers were on the sky, you know, you've taken a random images of stars and you've sort of drawn a load of triangles between them and the algorithm figures out from all those triangles where you are on the sky is now used to identify whale sharks in the wild. You know, those blue sharks with the white dots on them. And it's like the same algorithm, but, you know, a whole new application. And it's that kind of thing, that sort of unforeseen benefits

that you have no idea going to come out of being like, hey, can we take an image of a black hole? Like it would be really cool to do, but, you know, you have no idea what's going to come off the back of it. And I love that. I think it's so exciting. I guess that's kind of like, you know, your work is in black holes, so seeing that photo, you know, probably have some direct applications in what you do, but then seeing it also, what we're doing there can affect other things. That, you know, that must be quite inspiring both for you and for other people working like scientists across the world. Yeah, massively so. Like, I, one of the examples I love in terms of an inspiring of scientists is there is a web platform called the Zuniverse, which started

when the team that I now work in who researched the shapes of galaxies, they had a million images of galaxies, and there wasn't enough of them to physically go through them all and say, this one is a beautiful spiral shape, this one is more of a blob shape. And so they put them online for people to classify, because it's not really a difficult task. Like a five-year-old could tell whether it was a spiral or a blob. And so people loved it. You know, Radio 4 listeners in particular absolutely loved it. I think they shut down the server 24 hours after it launched.

And, you know, we never knew. I mean, my team, I wasn't there at the time. It was 10 or 11 years ago now. They never knew at the time what it would lead to, this one website that they put up. It's now this whole platform of 100 other science projects that are taking place that are all under the header of the Zuniverse, like universe but zooniverse.

And one of the projects they're now running is called the planetary response network. And instead of using the satellites in space to look out at galaxies, they've turned them back on Earth. And anytime there's a natural disaster, they're taking satellite imagery data and showing it to the sort of before the natural disaster image and the after the natural disaster image and saying, you know, label where there are roadblocks. label where a helicopter has space to land, show us where the flood areas are. So that's literally just been launched again after Hurricane Dorian hit the Bahamas a couple weeks ago. And so they're

asking people to label of the satellite imagery data. And that was a platform again that was built to help astronomers classify the shapes of galaxies and is now being used by humanitarian and aid workers to help people after a natural disaster, which I get it. It's just one of those things where you realize by asking one question, you've all of a sudden inspired someone else to go, oh, hey, you never thought of this, but we could do this with it, which I think is incredible. Is that something that you have to do? Like when you're coming up with, like, you know, your research, do you then have to sort of think, how can this be applied in a different way? Or is that something that you just hope someone else will pick up?

Yeah, I think it's something that you, you can't think of, right? You can't start thinking of like, oh, the unforeseen benefits, because it's so difficult to think of those. It's, I think astronomy definitely comes under the header of what we call blue sky research, this idea that you're not driven by the need for something, or, you know, for example, like a cure for a disease or the answer to a question or whatever, it's, it's asking questions for questions sake almost. It's the freedom to say, well, I want to ask this question, but who knows where it might lead me. And then it's for other people then to come in and say,

have you thought about doing it with this? Or have you thought about how this can affect this other area? You know, not everyone can have infinite expertise as much as some of us might wish we did. And so, you know, it's a team effort. It's collaborative, right, amongst all scientists, which is what I love about working in science, I think, the most. Does that mean that sort of astronomy is kind of like a philosophical science in a way?

Yeah, massively. I mean, that's how it was originally, you know, not pitch, that's the wrong word, but that's how astronomy originally came to be, right? The people who were answering these questions were the philosophers, you know, the Greek-Arabian, Persian kind of philosophers were answering the big questions about the universe. And that's what always makes me laugh about astronomy is that, you know, people find out you're an astrophysist, and sure, they want to know about black holes, but also they want to know whether you think aliens exist. and where life came from. And you just think that's well beyond me.

You know, I just sit at my desk, crunching data about black holes. How do I have the clout to answer this age-old question about whether we think we're alone in the universe? But it's also amazing to think that you kind of do have a little bit of that background knowledge that gives you the ability to philosophize over some of the big questions. I guess in that sort of situation your spaces you know what was it Douglas Adams said

space is big like really really big really big and then so when you sort of studying something so mind-nummingly big you must have like a different frame of mind of how you sort of contextualize and put things in a way so that we can understand them here and just as regular human beings on earth a little bit yeah I it is a bit weird because the scale that you deal with is ridiculous. And sometimes, you know, when you're at your desk or on the train, on your commute, whatever you're doing and you're, you know, going through some numbers, you don't really think about the scale of it. You just think about relative to another thing you've, you know, you've thought about. So, you know, this black hole is 10 billion times the master's sun. This one's

one million times the master's sun. You're not really picturing what that actually looks like. You're just thinking like, oh, that one's 10 times smaller, you know. Um, um, But sometimes you do have to contextualize it a little bit. You know, putting things into scales that we can, you know, comprehend, saying, you know, this event horizon of a black hole, the event horizon being the point at which if you cross it, there's no returning, you know, is the size of the solar system. Like, that's how big this thing is. You know, like, you sometimes do have to think that. And even when you're thinking about stars as well, I know that there's a star in the sky called Beetlejuice, which people might. or betelgoose, how people want to pronounce it.

It's in Orion, the constellation. So people might be quite familiar with it. It's sort of the left shoulder of Orion as you look at it. And it's quite a very red star, like just sort of left of Orion's belt. And it's what we call a red giant star. And it's huge, right? It's absolutely huge. And to really comprehend the scale, I always say, okay, well, if the sun was the size of a tennis ball,

which is already quite difficult to picture because the sun is big. and we know that it's very, very big. But if the sun was the size of a tennis ball, then Beetlejuice would be the size of the London eye. Blimey. Yeah. That's pretty. Yeah, exactly.

And then when you think about like, and then, you know, the black holes of the size of the solar system, but sometimes it's very, very difficult to wrap your head around it. And so I like to think about it and sort of like ratios, you know, to everything else. So one of my unit in Asterisics that people always laugh at is the point. parsec, right? It's that famous line in Star Wars that's like, oh, we can make the Kessel run in 12 parsecs or whatever. And it's a unit of distance. So Star Wars fans have tried very, very hard to come up with a reason that he might have said that in that context. But I always think about,

you know, the distance to the nearest stars is in parsecs, which is something like three times 10 to the 19 meters away, which is scientific notation for meaning a three. with 19 zeros after it, meters, right? So it's very far. Yeah. If I then start thinking, okay, well, if those are the nearest stars, how far away is the center of the Milky Way, you start getting to ridiculous numbers, not that three with 19 zeros after it wasn't already a ridiculous number, but you get to ridiculous numbers, right? So instead we use like something like a parsec. And so he's okay, distance to nearest stars is

parsec. Distance to center of Milky Way, kill a parsec. So thousands of parsecs. Distance to nearest galaxy, mega parsecs. You know, you're going up in like a thousand every time, a megaparsec being a million parsec. And then, you know, sort of distance to nearest like cluster and the sort of edges of the universe, you're getting towards the gigaparsecs, like a billion parsecs. So you have, you have those scales in your head. You're just, you're jumping by thousands every time rather than by like one every time. So that's how you kind of can try and deal with it anyway. Yeah. I mean, already my mind. is, is, feels like it's grown the size of a parsec, at least.

Just, just thinking that. But then also, I'm now thinking also at the, you know, what was it? The, however old the, the universe is, it started as a point in the Big Bang. And now it's gigaparsecs, uh, in size. That's, that is, must be that quite, there's a lot there to cover as a, as an astronomer. Um, every day. Yeah, it's a pretty, it's a pretty sobering thought, really. when you think about how large it is.

And like you say, there's just so much up there. You know, when you think about we always like to, not that there's rivalry between scientists, but we always like to joke with other scientists that, you know, they're focused on just the stuff on Earth, you know. They've only got the stuff on Earth to bother about. We've got like gigaparcex worth of universe, you know, that we have to study.

So we always joke there's a lot more for us to do. But yeah, when, I mean, people often ask me, and I talk about this in my book as well, whether that scale of the universe is scary, you know, and it can make a lot of people feel quite anxious in the way that it sort of, not belittles human endeavors, but, you know, it can make them feel very small. And like, I don't feel like that when I think about the scale. I understand why people do. But instead I say to people, well, instead of thinking like that, think about how it means there's like infinite possibilities there's like infinite stuff you could do or you could go or you could be and that i think is really exciting thought that there's just so much

out there you know that you could do and you could be a part of and i and i think that's a better way of looking at it than feeling really small yeah i guess um as as an astronomer like there's lots of different parts of, you know, different types of astronomy and all that. As you say, there's an infinite amount of things to do. How do you decide what it is that you're going to study? And what, you know, what does the day, what does an astronomer's day look like, essentially? Yeah, good question. I guess it's just one of those things that, you know, what you find the most interesting.

I ended up with sort of black holes and galaxies for a while. I thought I wanted to do like exoplanets, you know, planets. you know, planets around other stars in our solar system, because that sounded really cool and exciting as well. And it's often really difficult to narrow it down because there just is so much stuff that's exciting, so much stuff that we don't know about or enough about. And the end of the day, it's just what you want to spend your days doing, really. So I am an observer rather than a theorist or rather than someone who simulates something on their computer. So a theorist, for example, would be someone who, you know, very typically coming up with ideas,

seeing if they can work out the maths to describe that theory, for example. Hey, you know, the traditional sort of like chalk and a blackboard kind of a thing. You then got someone who is a simulationist. I don't think that's a word, but let's go with it. And there's someone who's saying, okay, can I simulate either the whole universe or this specific galaxy or this specific object in the universe? can I simulate it by putting in all the known laws of physics into a computer and they code that up themselves and then like run that program and see what they get. You know, that that's very much

a really cool thing to do. But I don't want to do that much with computers. So I was like, let's be an observer. So I'm someone that kind of works in a little bit of a cycle, six months to a year, for example, where you would say, okay, I have this question that I want answered about the universe that I'm curious about. And you say, okay, how am I going to answer? that question. You say, well, I need this data to do it. So what you do is you write what's called a telescope proposal and you say this is what I want to do with this telescope and I need five nights in say March to do it. Can I have them? And then a committee will meet and go through them all and decide like which one's worthy of the time on the telescopes. And if you're lucky,

you'll get time. And then you'll get to go to some far flung tropical place somewhere like Hawaii or the Palmer or Chile where the telescopes are because they have to be up high on mountains and away from light pollution, you know, etc. So we're very lucky in that regard. And then you go to telescope, take your data, come back, and then you spend time, you know, in your office at a desk, analysing what you found, whether it was you've taken an image or whether you've taken what we call a spectra, which is where you split the light from an object through a prism and you get out like it's rainbow, like it's sort of quantum fingerprint of what's going on in terms of the light. If you're picturing, you know, pink void, dark side of the moon, you're on the right track.

And so you analyze that data and figure out whether it's going to be able to answer your question, which hopefully it will. And then once you think you have an answer, you then write up a scientific paper to describe that. You know, you'll write like an article explaining what you did, what you found, and you'll publish it to the world, essentially. after another scientist has read it and said, yes, this is, you know, okay science. This makes sense what we call peer review. And then it gets published and sometimes it makes it into the media as well. If, you know, the media think it's a really fun thing to report on, like the black hole image, for example,

or if we find another exoplanet that's very similar to Earth or something like that. And it works in a cycle in that sense because, you know, usually you write out that paper, you'll be like, well, this data didn't tell me this. And so now I have a new question. You better go write another telescope proposal. And so I like doing that with my day. Because, you know, your day is varied. You're either at a telescope or you're using a computer to analyze your data

and you are writing some code. Or you're writing a paper or you're making a graph or, you know, you're flying on a plane somewhere, whatever it might be. And it gives you a bit of variation. And then at the end of the day, it's, well, what do you want to be spending your time asking about? do you want to be spending your time asking about stars or galaxies or black holes? Like what makes you want to get out of bed in the morning a little bit, you know?

Yeah. And for me, that's black holes. That sort of brings me along in one way is the fact that that sounds like a very busy day, you know, for anyone. And yet still, we mentioned it earlier. You've got a YouTube channel that's a very popular YouTube channel. How come, why have you decided, you know, as you say, you're black holes specialist. You're looking at the stars all the time. Why have you decided to go, you know what, I'm just going to make a YouTube channel as well?

First of all, because it's fun, and it's fun to chat to people online about space, because space is cool. But also, I don't you remember there was an article, a couple months back, or maybe even a year ago now, that was talking about the rise of specifically flat earthers, these people that believe the earth is flat, and other conspiracy theories because of YouTube, essentially, because of the way the YouTube, YouTube algorithm works. You know, you watch one conspiracy video and all of a sudden you're led down the rabbit hole of conspiracy videos. I'm sure we've all done it falling down a YouTube rabbit hole at some point. And, you know, so much so that there's now like conventions for people who believe the earth is flat. And the thing is, if you watch some of these videos, they're clearly

intelligent people in the sense that they have been able to come up with this theory, come up with ways to test the theory, the step is they don't then change their worldview when the evidence shows them that that isn't the case, for example. And that's what science is, really. It's not being emotionally attached to a theory. It's being able to change your mind and to revise something and say, oh, we got this wrong. You have to be objective and logical about it. And that's what gets me is that, you know, and I think a lot of these people who are intelligent people, fought on this rabbit hall are convinced by these people who are, you know, speaking to them like their teachers did at school, for example, but also as if it's more of a conversation

and therefore they believe it because also they're saying, well, you know, when you see this, clearly this is the case. And people really resonate with that. And I remember in the article that talked about this, which I think was on the BBC actually, they interviewed someone who'd done the study and she said what we have to do is basically flood YouTube with actual scientists talking about, you know, more legitimate theories, for example, or, you know, why this isn't the case, for example. Now, I haven't made a why the earth is round video yet or why the earth is not flat because I can just be like, I don't know, take a flight from London to Australia and come back by LA. But, you know, it's important, I think.

to have scientists on YouTube, not even just scientists, but all professionals, experts, whatever you want to call them, talking to people openly, saying, yes, there are things that we don't know, and that's okay. But this is the way we work it out,

and this is what evidence-based research looks like. To combat a little bit of this sort of, you know, like the public are sick of experts kind of viewpoint as well because there's a reason that, you know, people come out with what they do. It's based on evidence. It's not opinion, you know. And I think it's important. And one of the reasons is because I don't think that that's how science is currently taught in schools. I think science in schools is very much, this is it, this is the fact. And it comes across, like, this has always been known in this way. Right. And in fact, I think there was only one time in

science where that didn't, we didn't do it that way. I think we was learning about the structure of an atom. So I remember this being on the GCSE syllabus. So I'm sure there's some listeners that also will remember this where you went from sort of like the plum-pudding model, you know, all the way through to the model that we do have now. And I remember being like this, I mean, that was one bit about science that I was like, wow, this is amazing. This is the bit that really hooked me into science. And I realized it was because it was like evidence-based research. It was almost like a, like a crime novel in a way, you know, like sifting through the evidence to find out who done it. That is essentially what science is. It's not just equations and facts that have always been known in

that way, you know? And so I think by doing more stuff on YouTube, people become more engaged, either later in life or earlier in life, whenever it is, and realize that, you know, this is how science happens and make it a bit more transparent for people because it can seem a little bit, you know, pake in a way and very sort of on a pedestal sometimes and you're like no it's not on a pedestal we're just normal people just doing some evidence based research so obviously your your channel is sort of showing these things in general about space that they just go you know this is how we got here and this is why we understand that is it is it important that you get like a particular demographic is it like young people you're targeting and how important is it for them to to see people such as

yourselves doing this sort of talking about the sort of saying hey this is what i do or is it like you know just everyone is it these let's say flat earther type people who essentially need to be told some quality science yeah so i don't specifically target anybody i just kind of say my piece and i'm just like anybody who's interested can watch it i think um obviously the youtube algorithm is another thing who the YouTube algorithm obviously recommends the video to who it thinks will like it. So I don't really have much control over that. But the way my videos are made is sort of the way we're chatting now. It's like no prior assumed knowledge.

You know, there's no barrier to entry. And it's just someone who thinks space is really cool chatting about it. And then also, you know, responding in the comments if you want to ask a follow-up question or a different question entirely, which I think is really fun for people, you know, making it very open. feel like it is a conversation. But I think it definitely is important to have people online openly talking about it, also openly being human and making mistakes. So I always leave my bloopers in, for example, like, you know, asking Siri how far away Andromeda is because I can't remember or, you know, pronouncing so many different words wrong because I've never said them aloud

before or, you know, just sneezing. I don't know what it is. I just think like I'm completely a human being. But also, I get a lot of messages from people with young kids that say they've been incredibly inspired to see someone online, you know, just openly talking about science in that way and looking, you know, for all intents and purposes, someone that they can sort of associate with, like, you know, everyone else they see online, whether it might be a beauty blogger or whatever it is, you know, doing YouTube videos in the exact same way, but you just haven't to be talking

about science. Specifically, obviously, people with young daughters, I think, given that, but also, you know, people who are working in science now, who are female, who say, oh, I saw you in one of your bloopers, be like, oh, no, I just chipped a nail and be really annoyed about it, because you want to paint your nails and have them look nice, and that's okay to do that and be a scientist. I think there's a, this weird, I don't know where it's come from, but there's this weird thing about, like, you have to be a certain way to be a scientist, you know, the sort of atypical Einstein lookalike with a lab coat kind of thing. Very masculine in that sense, but it's not the case at all. You can still love nail polish and want to chat about black holes in the next sentence is my point.

And I just think it's, you know, like it seems like a no-brainer in a way, but it's still really important to just get that out there. Yeah. No, obviously, there's obviously an issue and the gender gap in STEM is quite a problem. Is your, do you think your video is a really good way to get, to tell, you know, especially young, young girls that, you know, there are females who are doing science and, you know, we're doing some really cool stuff? Yeah, just kind of being a bit unapologetic about it, really. And then also like not bringing attention to it in a way, just being like, yeah, I'm here. Yeah. Cool. You know, in that kind of a sense. sense. Like I started a series with my friend in Oxford called Michaela Livingston Banks, who heads up sort of Oxford STEM outreach. And we create this series called Nailing Science. And the premise of the series is we interview a scientist about their research. And as they talk to us, we recreate

their research in scientifically accurate nail art on the fingernails. And we don't explain why we're doing this, we don't like describe at the beginning that that's what we're going to do, we just do it. And it's just like, because why not, right? Just have a bit of fun with it. Because you can, you know, life's too short to think that you can't. Sounds like a hidden talent that I didn't even know could be. Oh, no, I don't have this hidden talent. I can put nail polish on a nail. Michaela can like recreate intricate, like, accurate drawings of birds so much that you recognize that, oh, that's a sparrow and that's a robin, I can do stick figures and like basic drawings. Sometimes I win or we get the person

to vote for which one is their favorite because I do one hand and Michaela does another hand. Sometimes I do win, but most of the time Michaela wins. Brilliant. I should definitely have to look at that one and see what's there. One thing that I definitely have looked at is your new book. Obviously, you know, obviously you are an astronomer by day, a YouTuber by that. How come you wanted to go analog and write a book about space? I guess it's just a different media. You know, we kind of have this assumption that, you know,

everyone in the world is on social media and is talking to people online. and is using online. And you can get that sense from some of the YouTube figures, you know, so many billions of people log in every day and watch videos. But at the end of the day, there are some people that just really love a good book. And I'm one of them. I absolutely love reading. I was always reading as a kid. I still read now, you know, every night before I go to bed. And it's just such a way to just sort of switch off and relax a little bit. And I never thought that I would write a book, if I'm quite honest. I think I was told at GCSEs, that I wasn't a good writer because I write the way I talk. Now, that might not be a good way to

write an English essay. However, for a popular science book, you know, it's actually, apparently quite a good thing. So I just had a lot of fun with it, really. I didn't really set any expectations on myself, and I just let myself just chat the way I would when I was writing, when I would, you know, be sort of planning a YouTube video. And so what I've ended up with is this, really nice sort of short, digestible 10 essay kind of collection book about the sort of 10 things that you should know in space, like the 10 biggest ideas in space. You know the kind of thing that you'd want to crack out at a dinner party, you know, to be like, oh yeah, I know about dark matter. Yeah, did you know this? That kind of a thing. And I've written it, you know, with sort of my mom in

mind who, you know, did a GCSEs and then never did any signs past that again. You know, for people who either absolutely love space and, you know, want to read everything they can get their hands on, or people who've gone, you know what, space has always interested me, but I've always thought it was too hard, you know. Well, I always thought English was too hard, but I managed to write a book, so it's all about practice, you know? Like, and it's supposed to be sort of entry level for people who, you know, just really want to get to grips with what they can about space and just really learn some exciting stuff. And I think a book is a really great way to do that because it gives people to digest it in their own time, you know, at their own pace as well and go back to things.

And I think that's what's really nice about a book. Yeah. No, there's definitely, you know, the way how the chapters are essentially, I've, you know, having read it, I've, I understand so much more these things that I've been, you know, working on and covering for the last few years as well. So it's really helped me in that respect. But obviously, you know, you've got 10 things that you should know about it. How did you pick those 10 things? And were there some stuff that's actually really cool but just didn't make the cut? Yeah.

It was a bit difficult to sort of narrow it down a little bit. Obviously, I managed to sneak two chapters in there about black holes because I love black holes. But, you know, they're just the ones that just leapt out to me a little bit. You know, the ones where either always talking about because they're at the forefront of research right now. or, you know, we still don't know something, for example. There was a couple of things that maybe didn't make the cut. But I think the ones that got in there are the ones that, at least in my experience, of just, you know, being at parties or stuck on trains or planes

and people turning to you and asking what you do, they're the questions you always get back afterwards. You know, like what was before the Big Bang? How will the universe end? do aliens exist, that kind of thing. Yeah. And looking at it and saying, this is where we're at, and this is how we best understand it now,

but also stressing like that can change. And that's okay. And there's a lot of stuff we still don't know because as a kid, I read a lot of space books because I'm not afraid to say it, but I was a space nerd through and through. And I read these books and devoured them and thought that everything was already known.

You know, everything was presented as, like I said, Like, we've always known it, and that's the way it will always be understood. And I really wanted to stress with this book that it's not the case at all, that there's so much that we don't know. In fact, the last chapter is called There's More That We Don't Know Than We Do Know. And I think that's a really nice way to end it. That was Dr Becky Smethurst, whose book, Space, Ten Things You Should Know, is out now. You can find an extract of it on ScienceFocus.com, and we'll add a link.

in the show notes. Otherwise, if you like listening to our little chats, then please let us know with a rating or a review wherever you listen to your podcasts and tell your friends if you think they'll like it too. Next week, Marcel Dinesci explains the language of lying, which will be great and that's the truth, but for more mind-expanding science, the latest issue of BBC Science Focus magazine is on sale now. In it, you'll find why aging has an off-switch, why robots won't think like us, and how dark matter is hiding under our feet. As always, there's loads more inside. Thank you for listening to the Science Focus podcast from the BBC Science Focus magazine team. With the UK's best-selling science and technology monthly, available in print and in several digital formats throughout the world.

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