The Letter That Changed Mathematics

How did pages of mysterious “gibberish” sent from Madras find their way to one of Cambridge University’s most respected mathematicians? Were the strange formulas the work of a deluded mind - or breakthrough insights of an unknown genius? The author of that letter was Srinivasa Ramanujan. His story inspired two Hollywood blockbusters (Goodwill Hunting, The Man Who Knew Infinity) but his mind changed the shape of mathematics forever. Welcome to The Rest Is Science: Field Notes. Every Thursday, Hannah and Michael rummage through their personal troves of scientific treasure and source discoveries that explain our understanding the universe, oddities that scramble our brains, objects that hint at forces we’ll never see...and a few things that are essentially just plain cool. Expect deep dives into the science behind each pick, the spark that grabbed their attentions, and the sheer delight they get from sharing it all with you. They’ll also be tackling your questions, so email The Rest Is Science at [email protected] ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit ⁠⁠https://cancerresearchuk.org/restisscience⁠⁠ Cancer Research UK is a registered charity in England and Wales (1089464), Scotland (SC041666), the Isle of Man (1103) and Jersey (247). A company limited by guarantee. Registered company in England and Wales (4325234) and the Isle of Man (5713F). Registered address: 2 Redman Place, London, E20 1JQ. EXCLUSIVE NordVPN Deal ➼ https://nordvpn.com/restisscience Try it risk-free now with a 30-day money-back guarantee 🌍 ------------------- Find The Rest Is Science all over the internet by ⁠clicking here.⁠ -------------------Video Producer: Adam ThorntonVideo & Social: Bex TyrrellAssistant Producer: Imee MarriottProducer: Becki HillsSenior Producer: Lauren Armstrong-CarterHead Of Digital: Samuel OakleyExec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

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• 0:00Hannah Fry?

  This episode is brought to you by Cancer Research UK.

• 0:02Michael Stevens?

  Imagine this: inside all of us, billions of cells follow millions of instructions written in microscopic code. And when a new cell grows, it copies those instructions, but the smallest error can lead cancer to develop.

• 0:17Hannah Fry?

  Right, and this is the reason why there isn't a single cure for cancer, because, you know, there are more than 200 different types, each of them have got distinct characteristics, you know, different challenges, different mysteries. And that means that trying to cure cancer isn't like following a single path, it's like trying to map out an entire forest.

• 0:34Michael Stevens?

  That's right. And Cancer Research UK is the world's largest charitable funder of cancer research. I mean, their work spans more than 20 countries, with over 4,000 scientists, doctors and nurses pushing knowledge forward to save and improve lives worldwide.

• 0:50Hannah Fry?

  You know, over the last 50 years, the work that this charity has done has helped to double cancer survival in the UK. And you have to think about, that is more parents at the dinner table, right? That is more friends at their birthday parties, that is more people who are living longer, better lives.

• 1:08Michael Stevens?

  For more information about Cancer Research UK, their research, breakthroughs, and how you can support them, visit cancerresearchuk.org/rastoscience.

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• 1:50Speaker 03

  Hey Spotify listeners! When you travel with American Airlines, you'll enjoy comfort and convenience at every altitude. Before takeoff, unwind in the Admirals Club Lounge with curated self-serve offerings of hearty bites and refreshments. In-flight, stay connected with high-speed Wi-Fi. Sponsored by AT&T. Your journey is designed to feel easy from the moment you check in to the moment you arrive. No matter where you're going, American gets you there. Book now at aa.com.

• 2:16Speaker 04

  This episode is brought to you by Google Chrome. You think you know a browser, but Gemini and Chrome? That's new. It can help you with practically anything on the web, like restoring a vintage motorcycle from a 50-page restoration block, or finally break down that long article you've had open for weeks. Gemini and Chrome is here for it. Ready to make anything online make sense? There's no place like Chrome. Check responses set up required. Compatibility and availability varies 18 plus.

• 2:47Michael Stevens?

  Welcome to The Rest Is Science. This is Field Notes, a kind of expedition diary where Hannah and I track the discoveries, curiosities, riddles, and questions that have excited our minds recently. Now, what have you got for me today, Hannah?

• 3:01Hannah Fry?

  Okay, today I want to talk to you about, and I don't think this is an exaggeration, one of the most important pieces of paper in the history of mathematics.

• 3:09Michael Stevens?

  Oh, good.

• 3:10Hannah Fry?

  It's a big deal. I got to go and see it. I haven't got it with me today because I think it's locked behind about 15 doors under continual armed guard. I'm joking, but I'm going to get to what it is in a moment and why it ends up being so important. But the first thing I want to ask you about is, have you heard of a guy called Ramanujan?

• 3:33Michael Stevens?

  Yes, mathematician, Indian.

• 3:35Hannah Fry?

  Yeah, absolutely. So actually, he is the character that Good Will Hunting is based on, right? I mean, Good Will Hunting is like this modern version of the story, but essentially, the essence of that story is there's truth to it. We're talking just after 1900 here, okay? And at the time, there are these great titans of mathematics who are at Trinity College in Cambridge. One of them is called Hardy, and the other is his kind of co-collaborator, a guy called Littlewood. And as lots of mathematicians do, even to this day, they get all of these letters from people coming in and saying, "Oh, I've discovered something absolutely extraordinary. I've come up with a new formula for infinity, etc." Anyway, one day Hardy opens these letters,

• 4:19Hannah Fry?

  and he sees this letter that's come through in the post, and it's just a total load of absolute gibberish, right? Like, complete load of nonsense. The notation is all over the place. It's like pages and pages of formula. And he's like, "This is absolute junk." So he immediately just throws it in the bin and leaves it. And then he leaves, he kind of goes off for lunch and goes for a walk. And then later that evening, he finds himself sitting with his longtime collaborator, Littlewood. And he's like, I just can't get this thing out of my head because there was a couple of things in it, even though the the like notation of it was absolute nonsense. There were like a couple of bits in it that sort of, I feel like I've been struggling to understand myself for a number of years. So him and Littlewood go back into the to the wastepaper basket and they get this letter out of the bin and they start to go through it. And line

• 5:04Hannah Fry?

  by line, I mean, it is full of the absolute biggest load of junk in a lot of ways, in terms of the notation, in terms of there are no proofs anywhere, there's no, it's not rigorous at all, it's like a mess. However, contained within it are these like little ideas, these little like mathematical secrets, some of which Hardy knew that the rest of the world didn't know, and some of which were even beyond what Hardy himself thought that was was possible. And him and Littlewood were like, looking at this and being like, okay, you know what, either this person is crazy, either this is a letter that has come in from a madman, or, as is more likely, this has come in from a genius. And they

• 5:46Hannah Fry?

  decided that on the balance of probability, that if someone was a madman to send this letter, they wouldn't possibly have the imagination to come up with something quite so crazy. And so the only possible explanation was that this must be the real deal. And I should tell you, some of the like crazy things that appear in this letter are that if you add up one plus two plus three plus four plus five, all the way to infinity, you get minus one over twelve.

• 6:14Michael Stevens?

  Is that where that comes from?

• 6:15Hannah Fry?

  That's where that comes. Well, yes, that's one of the places that comes from. Yes, absolutely. I mean, can you imagine? I like trying to, I get letters like this now, right? So I am now a professor at Cambridge University. I get letters like this all the time. I open them and think they are nonsense. And there's a little bit of me that's like, oh, no, hang on a second. Maybe I could be missing out on an actual genius here. Maybe I could be a real genius. But can you imagine getting a letter from someone saying, if you add one, two, three, four, all the way up to infinity, it equals minus one over twelve? You would just dismiss it out of hand, surely?

• 6:45Michael Stevens?

  Yeah, you would think it was a joke. And you'd be concerned for the person. But you're right, to have the imagination to come up with that, but then also the confidence to send it to leading mathematicians. Would make me take a closer look.

• 6:58Hannah Fry?

  Right, absolutely. So that's exactly what Hardy does. He finds a way to contact the person who wrote in the letter, a person called Ramanujan. And he organizes for him to come over from India and become a resident in Trinity College in Cambridge. And when he does so, he realizes that the person in front of him, who is untrained, this kind of rough diamond, as it were, has the most extraordinary natural ability of basically any mathematician who has ever walked this earth. Not only that, with his only training being this textbook that's used for high school students, right? Like, there's no advanced mathematical ideas in it at all.

• 7:42Hannah Fry?

  He had managed by himself to advance the field of number theory further than the best, most well-funded minds across Cambridge and the rest of the world, right? On his own, he had managed to do things that had evaded other people. So the thing that I got to see, when I was first talking to Cambridge about moving over there as a professor, they organized this day for me where I got to go and see all of the really exciting things around Cambridge, right? Got to go meet the Vice Chancellor, got to go and, you know, see the, like, fancy halls and stuff. And there was one day, one afternoon, there was one bit where we got to go into the library and dig out their treasures. And they had the original Newton copy of Principia Mathematica, the textbook that he wrote, his handwritten annotations in it.

• 8:28Hannah Fry?

  Absolutely amazing. That's sort of the gem of their collection that everyone gets really excited about. And of course, I found that exciting. But then they were like, oh, and there's some stuff by some other mathematicians that we've dug out over there in the corner. We went over, had no idea that this is what we were going to find, but there was a folder with the original letter, the one that had been thrown in the bin.

• 8:50Hannah Fry?

  By Hardy and the subsequent follow ups. And I, I basically, I've never been more excited by anything in my entire life.

• 8:59Michael Stevens?

  What, what kind of mathematics was it? What, what was being argued or shown?

• 9:05Hannah Fry?

  So this is, it's number theory, essentially. So you are looking at different ways that you can partition series numbers. So I have sent over a couple of pictures that I took on the day.

• 9:17Michael Stevens?

  Oh, for today from Hannah Fry.

• 9:19Hannah Fry?

  There you go.

• 9:20Michael Stevens?

  Oh, wow. Okay.

• 9:22Hannah Fry?

  Right. So for starters, look how nice his handwriting is. That's absolutely.

• 9:25Michael Stevens?

  That's the first thing I was going to say.

• 9:28Michael Stevens?

  This is not a madman. This is an artist. It's so readable.

• 9:32Hannah Fry?

  It's so readable.

• 9:33Michael Stevens?

  Dear sir, I am very much qualified on perusing your letter of the eighth February. I mean, I'm not good at reading cursive, but I love this.

• 9:45Hannah Fry?

  This is readable, right? But this is someone who notices, actually, how crazy he sounds. Because there's a section here where it says, I told him that the sum of an infinite number of terms of the series one plus two plus three plus four plus, plus, plus, plus, equals minus one over 12 under my theory. If I tell you this, you will at once point out to me the lunatic asylum as my goal. Like, he knew it sounded crazy.

• 10:10Michael Stevens?

  Yeah.

• 10:10Hannah Fry?

  Knew it sounded crazy. And yet it turns out it's not crazy. It's absolutely correct. And not only that, but it turns out to be phenomenally useful in the field of string theory.

• 10:21Michael Stevens?

  Yep.

• 10:21Hannah Fry?

  It's an actual result that actually gets used by actual physicists.

• 10:25Michael Stevens?

  Yeah, and Number File has a fantastic video on it. It sounds like a joke, and yet there are ways of looking at the sum of all the integers and you go, well, how can it not be negative 1/12?

• 10:37Hannah Fry?

  Yeah. That, that proof from, from, from Number File is, I think it's pretty controversial. I think that's probably fair to say.

• 10:43Michael Stevens?

  Well, it's controversial, but it really forces you to say, well, what is mathematics? And what are we doing here? Because there are different kinds of intuitions and different sorts of, you know, behaviors and, and, and things to focus on that really can make something like this true.

• 10:59Hannah Fry?

  Yeah, absolutely. The other thing about this Ramenujan story is that I should add is that actually the winter in Cambridge, it really didn't suit him, right? This is also nineteen fourteen, nineteen fifteen, so right at the very beginning of the First World War. He was vegetarian and it was almost impossible for him to get the nourishment that he needed while there were rations and so on in place. There was nowhere in Cambridge that sold vegetarian food around that time, I believe. But he really didn't do very well and around three years later, he ended up passing away. He contracted tuberculosis and passed away. And there's this really beautiful story about Hardy, who I have to tell you, right?

• 11:42Hannah Fry?

  Hardy is like, he's sort of the most upright of people, right? If you imagine a really traditional English gentleman, that's Hardy all over. I mean, this is like, this is a man who had five things that he was most proud of in the world. And number five was that he didn't have any children. He used to boast about how happy he was that none of his maths was any use whatsoever to anybody. Which is a bit of a shame because it ended up being the foundation of modern cryptography. But he's like this very, very upright man, loves cricket and mathematics and nothing else, not interested in another single thing. But he described his encounter with Ramenujan as the most romantic encounter of his life.

• 12:26Hannah Fry?

  Or the only romantic encounter of his life. Oh. Yeah, which is quite sad really in a lot of ways. But he really thought that he was, this man was absolutely extraordinary, like had been sent by God. And when Ramenujan was in the hospital, when he was extremely sick and about to pass away, Hardy got a taxi down, this is, he was in Putney, in hospital in Putney. So Hardy got a taxi all the way over to go and see him and sit with his friend. And he didn't know what to say, right? He was rubbish at small talk, sort of like a very awkward guy. And he sat there and said, oh, the the number of the taxi that I got here was was seventeen twenty nine, like a extremely unremarkable number.

• 13:09Hannah Fry?

  And seventeen twenty nine has now become a sort of inside joke for mathematicians because Ramanujan, without even pausing, this is a man who is on his deathbed, right? Like, one of the most gifted mathematicians to have ever lived, immediately responds, seventeen twenty nine isn't uninteresting at all. It's the smallest number that can be comprised of two cube numbers added together in two different ways. Which, I mean, I don't know about you, Michael, but that would take me about an afternoon to work that out.

• 13:38Michael Stevens?

  Uh, yeah, and on my deathbed, I'll probably say something like,

• 13:45Michael Stevens?

  nothing that becomes a mathematical meme for the centuries.

• 13:48Hannah Fry?

  No, absolutely not. It's just a really lovely story. And I mean, I think it's sort of like, I think the kind of the idea of there being these geniuses who walk the earth is there's something so appealing about it. There's something like really magnetic about it. I also think it's sort of problematic because almost all science and maths and advancing of of humanity is not done by, you know, the absolute like one in a squillions. It's done by big teams of people who just are normal people who work really hard, right?

• 14:19Michael Stevens?

  Yeah, right. Yeah, I mean, the great man theory of history and culture and discovery, it forgets the fact that like there needed to be doctors to help Ramanujan. There needed to be like literally the messengers who would send the correspondences back and forth so that these mathematical conversations could happen. Like, you need everything, every one.

• 14:42Hannah Fry?

  There's also, I think, this idea that, you know, not everyone is Usain Bolt, but that doesn't mean that you can't have extreme value in sort of going for a jog around your park on a on a Sunday afternoon, you know? You sort of don't have to be a genius.

• 14:57Michael Stevens?

  And and we all stand on the shoulders of giants. For every Ramanujan, there's a high school math textbook that. Set him on that path.

• 15:07Hannah Fry?

  Yeah, absolutely. You do get these things popping up, though, in math sometimes. You do get people coming from nowhere with like no formal training, no connection.

• 15:15Michael Stevens?

  First of all, I'll say that not only do they just kind of pop up, they're often quite young.

• 15:20Hannah Fry?

  Yeah.

• 15:20Michael Stevens?

  I'm sure you've heard a lot about this like sweet spot for mathematicians and their productivity. And it's like in the early twenties. What are your thoughts on that? Do you feel like you've got some mathematical discovery that you're gonna you're gonna stumble upon in the next couple of decades and you're gonna throw the average off?

• 15:37Hannah Fry?

  Oh, no, I'm way too old, Michael.

• 15:39Michael Stevens?

  Way too old, yeah.

• 15:40Hannah Fry?

  Way too old. Also, I'm just enjoying my time spent with you far too much to to be thinking deeply about about mathematical truths and reality.

• 15:48Michael Stevens?

  Oh, so now you're blaming me for keeping you from changing the world mathematically. I'll take it. I'll take that responsibility.

• 15:55Hannah Fry?

  Okay, that's good. Yeah, it is. It does seem to be a young person's game. I mean, actually, they always used to say it was a young man's game. And I think sort of real emphasis there, only one one woman has ever won the Fields Medal. This is a bit like the Nobel Prize for Mathematics, except it's way harder because you can only receive it if you're under forty and they only give it out every four years.

• 16:17Michael Stevens?

  Wow.

• 16:18Hannah Fry?

  But yeah, only one woman ever has won it. So, um, yeah.

• 16:22Michael Stevens?

  Oh, my gosh, I've got two months left to win that.

• 16:25Hannah Fry?

  Uh oh, get get, come on, let's do this.

• 16:28Michael Stevens?

  Do you have to be under forty or does your discovery just have to have been made before you were forty?

• 16:32Hannah Fry?

  No, you receive the medal before you're forty.

• 16:35Michael Stevens?

  When's the next ceremony?

• 16:37Hannah Fry?

  Twenty twenty six. That's the next Fields Medal.

• 16:39Michael Stevens?

  Uh, but what month?

• 16:41Hannah Fry?

  When's your birthday?

• 16:43Michael Stevens?

  January twenty third. It's really soon in the year. But it only happens every four years? Twenty thirty, twenty thirty four, twenty thirty eight. Let's see, my daughter is gonna be, she won't be forty until twenty fifty nine.

• 17:01Hannah Fry?

  She's got time.

• 17:02Michael Stevens?

  She's got a chance. All right. So I'm looking at these photos. I still have them up on my computer and there's one where you're actually standing next to a bound book, a hardcover bound book. And is that what contains these letters?

• 17:14Hannah Fry?

  No. So that is Newton's original copy of Principia Mathematica.

• 17:19Michael Stevens?

  Oh, no kidding. I love that it's on a pillow.

• 17:21Hannah Fry?

  I know.

• 17:22Michael Stevens?

  Just needs to be tucked in.

• 17:25Hannah Fry?

  It's so precious. The thing is, is that even though it's on a pillow, if you like flick through these, there's one point clearly where it's got mouldy. So

• 17:33Michael Stevens?

  No.

• 17:34Hannah Fry?

  It's like these pages are just covered in black mould.

• 17:36Michael Stevens?

  I love that. You know, Richard Feynman once said something like, if you think about something for a really long time, you can write down all of your thoughts in a book and then put it in on a shelf in a library full of basically what happens when people think about things. And it was just such a humbling reminder that like, the mould doesn't care what's on the page.

• 17:55Hannah Fry?

  No, no, absolutely not. Or whose hand had like turned the pages.

• 17:59Michael Stevens?

  Yeah.

• 18:00Hannah Fry?

  There are some nice things in there though. There's like a couple of bits where Newton has done a couple of little doodles. So there's like, I mean, he's, he's got much messier handwriting than Ramanujan, that's why I will say. But there's, there's like a few little, little graphs that he's drawn there, like little tangents and stuff. There's a bit where he's sort of correcting the print, being like, no, no, no, no, I don't like this at all. I want to change it completely. I mean, my Latin's not great, so I'm assuming that's what it says. But there's one bit which I quite like, little Newton doodle.

• 18:30Michael Stevens?

  A Newtonian emoji.

• 18:34Hannah Fry?

  You know, in the Royal Society where they elect fellows, like really great people from, from science and mathematics, they, they elect them as fellows. And it was the institution, it's been sort of the longest running scientific institution in kind of continuous existence in the entire world, been going since the 1600s. Newton was like a very prominent early president of this place. Anyway, when you are elected as a fellow, which is very, very hard to do, you get one black ball and you're out. When you get elected, you get to sign your name in this original book, which has everybody in it, all the way back to the 1600s. And the thing that's really nice is that obviously Newton's signature is in there,

• 19:14Hannah Fry?

  but the person underneath Newton's signature is completely rubbed out because for centuries, people have flicked backwards, put their finger on the page, you're going, oh, look, it's Newton.

• 19:23Michael Stevens?

  And they've pointed at Newton's smudging the name below him. Oh, I love that.

• 19:30Hannah Fry?

  Erased, literally erased from history. This does happen every now and then, someone pops up from nowhere who is sort of outside of the like usual institutions, but has done something really extraordinary. This happened a few years ago, there was a guy called Grigori Perlman. I don't know if you've come across this guy.

• 19:47Michael Stevens?

  Yes, I've seen like photos on Reddit of him, like taken candidly from his back while he's waiting at an intersection and they're like, we found him. And it's just such a mystery.

• 19:58Hannah Fry?

  He is so fascinating. Okay, so in the year 2000, the Clay Maths Institute, they they decided that they would write down the seven most important unsolved problems in mathematics, right? Like the biggest mysteries and they were like, we'll give a million dollars to anyone who could solve one of these. And all of them almost have stood unsolved for a quarter of a century. But from nowhere a few years ago, this proof landed on the internet by Grigori Perlman, a Russian mathematician. Mathematician, I mean, I'm sort of saying that, but like he wasn't associated with anywhere else. He solved this like very important theorem called the Poncaré conjecture. And people initially were like very skeptical, where's this guy come from? You know, you don't just sort of, I mean, you may as well like, you may as well have put it up on Twitter, you know?

• 20:43Hannah Fry?

  Like you don't expect sort of a random Twitter poster to have solved it. But people very carefully went through and checked and it was absolutely correct. Like this whole thing was totally, totally spot on. And so, you know, people were like, well, well done you. Have all of these prizes, have the medal, have the, have the

• 21:03Michael Stevens?

  The million dollars.

• 21:04Hannah Fry?

  Million dollars, right? But the thing is, is the million dollar prize, it was a ceremony that was going to be held in Spain. And Grigori Perlman, he replied that to go to Spain would mean one day travelling, one day to collect the prize, one day to return home, and that would be three days when he wouldn't be able to do mathematics. So he turned it down.

• 21:22Michael Stevens?

  Wow.

• 21:24Hannah Fry?

  Says something, doesn't it?

• 21:25Michael Stevens?

  Yeah.

• 21:26Hannah Fry?

  Yeah, but he hides from everybody. He's like, he doesn't want to give talks. He doesn't want to be invited to things. He just wants to do his own thing. So yeah, hence people stalking him and putting photos of him on the internet.

• 21:38Michael Stevens?

  Living his best life alone. Well, we don't know if he's alone. He might have like a bunch of friends.

• 21:43Hannah Fry?

  So he did live with his mom in an apartment in Moscow for when the prize was suggested.

• 21:48Michael Stevens?

  Okay.

• 21:49Hannah Fry?

  Which is like, you know, actually, I think a million dollars in Moscow is like, it's enough money to um to like be noticed, but not enough money to protect yourself. So I think that might be one of the reasons.

• 22:01Michael Stevens?

  Oh, okay. Yeah, that makes sense. Or maybe he just doesn't want his mom to know he's a nerd.

• 22:09Hannah Fry?

  I think it might have leaked out on the side.

• 22:10Michael Stevens?

  She's like, what's that letter you received? And he's like, oh, junk mail. Oh, I gotta go uh uh lift some weights.

• 22:19Hannah Fry?

  Is that what you were like in your teenage years, Michael?

• 22:21Michael Stevens?

  No, no, I was very proud to be as nerdy as possible.

• 22:26Hannah Fry?

  Me too. Absolutely. Shall we go to break?

• 22:35Michael Stevens?

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• 23:48Speaker 03

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• 24:14Speaker 04

  This episode is brought to you by Google Chrome. You think you know a browser, but Gemini and Chrome, that's new. It can help you with practically anything on the web, like restoring a vintage motorcycle from a 50-page restoration block, or finally break down that long article you've had open for weeks. Gemini and Chrome is here for it. Ready to make anything online make sense? There's no place like Chrome. Check responses set up require compatibility and availability varies 18+. [Music]

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• 25:16Michael Stevens?

  Welcome back from the break. We are refueled and we are ready for some questions.

• 25:22Hannah Fry?

  You survived. Congratulations.

• 25:24Michael Stevens?

  We've got people who desperately need answers. For example, Becky asks, "Why do I sneeze when I first have a ment or a piece of chewing gum?"

• 25:34Hannah Fry?

  Well, okay, first things first, Becky. I think you need a lozenge for that sore throat.

• 25:38Michael Stevens?

  That's what I was thinking. It's ridiculous, Becky.

• 25:40Hannah Fry?

  Chewing gum is not the thing that you should be consuming right now. Okay, basically, there are these nerves in your face, right? There's one called the trigeminal nerve, like this, it's a monster. It's like an absolute beast sitting behind your face. And it's responsible for all of the sensation that you get and also the movement of your main muscles, your chewing muscles. And that nerve essentially holds the power to hit the sneeze button, right? So that's the nerve that gets triggered if like a little bit of dust or a microbe or something ends up in your nose and you're like, okay, need to eject this immediately, let's sneeze. But what can happen is when you, when you eat something like mint or for some people, when you look at a bright light, right? This is also having, it's sort of like, there's, there's, that nerve, it gets a slight sensation

• 26:25Hannah Fry?

  that it gets confused by and it just hits the eject button instead. Instead of being like, it's, it's cool, don't worry about it, it's a bit of mint.

• 26:32Michael Stevens?

  Yeah.

• 26:32Hannah Fry?

  The, um, the looking at bright light one is because the optic nerve runs really close to the other nerve and like the, the sort of insulation between the two of them can be a bit dodgy. And so you can get sort of a mixed message, quite literally like a faulty wiring of like looking at a bright light and this nerve being like, whoa, something, sneeze.

• 26:53Michael Stevens?

  How cool. Yeah, yeah, the optic nerve, any nerve near the trigeminal nerve, overstimulated, it can leak in and then it, yeah, the trigeminal nerve says there's something that needs to get out of here, sneeze.

• 27:04Hannah Fry?

  Have a sneezing fit. It'd be quite bad if you worked in a mint factory, wouldn't it?

• 27:09Michael Stevens?

  Well, yeah, I've never had that kind of effect. I, I don't sneeze when I see bright, bright lights, but I've heard people talk about it. And I've been like, wow, you've got leaky nerves, dude.

• 27:22Hannah Fry?

  You are miswired. Yeah. The only way actually that I can make myself sneeze is, uh, which everyone can do, right? Is to get something really small. Don't do this, but like a feather and like tickle the inside of your nose, that will, that will work if you ever want to sneeze. Some people quite like sneezing, I think, don't they?

• 27:40Michael Stevens?

  Oh yeah, some people really like it. Like it's their, it's their bag, baby.

• 27:45Hannah Fry?

  What, like, like, like in a kinky way?

• 27:48Michael Stevens?

  Yeah, cause it, it represents like a moment where you lose control.

• 27:53Michael Stevens?

  It's surrendering yourself to the sneeze.

• 27:55Hannah Fry?

  Wow, you better believe I'm going to be searching some of the dark corners of Reddit later.

• 27:59Michael Stevens?

  Oh yeah, I can show you my friends in the forums.

• 28:03Michael Stevens?

  But, uh, that's a good time to move on to Harry B.

• 28:06Hannah Fry?

  It probably is. Wait, let me ask you this one. Let me ask you this one. What is your favorite and least favorite element and why?

• 28:13Michael Stevens?

  My favorite and least favorite element? My favorite element is sulfur because my father was a, a sulfur engineer. He was a, a chemical engineer who worked especially in sulfur recovery from refineries. They've got a lot of sulfur that they don't need. And he loved sulfur. He had jars of sulfur around the house's decoration and he always wanted to get a tattoo of a sulfur molecule. My least favorite, I don't know, it seems so mean to be all like judgmental about just a way matter can be arranged. I guess, should I go with something that's dangerous? Let me think.

• 28:52Hannah Fry?

  Yeah, go on. What's the most dangerous?

• 28:54Michael Stevens?

  You know, like the most dangerous, I'd say like some enriched plutonium would be really bad.

• 28:59Hannah Fry?

  Yeah.

• 29:00Michael Stevens?

  And yet plutonium, I think, can also do a lot of good when used in the right way.

• 29:04Hannah Fry?

  What about like, is it thallium that's like really poisonous? Some of them are very bad for you.

• 29:09Michael Stevens?

  Yeah, but they've got to have redeeming qualities. There's a whole part of the periodic table that's full of like the forgettable elements where their their properties are all like, yeah, it's a silvery metal that is sometimes used in optics. And you look at its name and the name is like flubium. And you're like, oh, like, is that really an element? And you have to look it up and you're like, yep, it's got a Wikipedia page. Wow, I never hear about that. But I don't want to be mean to them either. Is there an overrated element? I sometimes think carbon gets talked about a lot.

• 29:44Hannah Fry?

  It does. It's also, I don't know if you know this, quite a big deal.

• 29:49Michael Stevens?

  Uh, you're one of those carbon heads. I see. I see. Maybe it's just that I love sulfur too much. But what about you? What's your least and most favorite element?

• 29:59Hannah Fry?

  You're right. Having a least favorite is really difficult. I was, I was gonna go for argon as my least favorite, just because it's like, wow, boring, doesn't do anything.

• 30:07Michael Stevens?

  It does so much. Ever heard of an incandescent light bulb?

• 30:10Hannah Fry?

  I know. But then also, I do, the other thing I was thinking about was, because the thing about argon is it does react with anything, right? It's like, it just happily runs around on its own. It's like the ultimate loner, basically. But the thing about argon is that actually they use it to detect neutrinos. So there was one point where I got to go to CERN and I just so happened to be there when they were building this like giant neutrino detector. You know, these, these sort of like particles that are. Uh that incredibly difficult to to sense um that leave almost no discernible imprint on the world around them. But um if you have a giant tank of liquid argon, then you can like slightly detect these little trails that are left by these neutrinos as they go through.

• 30:54Hannah Fry?

  Anyway, this tank, right, that they had was like lined with gold on the inside. That was pretty cool. Um but the liquid argon that they had in it, I was like, that is, that's a, that's an absolute beast. How on earth did you get the funding for that? Liquid argon is apparently cheaper than Coca-Cola by the liter.

• 31:10Michael Stevens?

  No kidding. How cold is it?

• 31:13Hannah Fry?

  I actually don't know.

• 31:14Michael Stevens?

  We got a question from Michael S. How cold is liquid argon?

• 31:18Hannah Fry?

  How cold is liquid argon?

• 31:19Michael Stevens?

  So I guess argon uh condensing temp, that is negative three hundred and two Fahrenheit, uh negative one hundred and eighty five Celsius.

• 31:31Hannah Fry?

  Not that cold. I mean, cold and not, not like insane cold.

• 31:35Michael Stevens?

  Basically, the point is it sounds like argon might be your favorite element.

• 31:38Hannah Fry?

  I think it might be. You know, I was also, I was gonna go for gold, just because I think like actually, um I mean, it's a bit, it's a bit of an easy one, isn't it? A bit of an easy one.

• 31:47Michael Stevens?

  No, no, no. Gold has a lot going for it. I think if you're gonna, if you're gonna say argon is bad for just hanging around and not reacting with stuff, how can then you then say gold is great? Gold famously doesn't react with stuff. It's precious. It doesn't tarnish. Um the only thing that gets rid of it is Aqua Reja, um dissolves it at least.

• 32:09Hannah Fry?

  Yeah, which is actually the famous story about the uh the Nobel Prize winner who during the Second World War, uh because was when you get a Nobel Prize, it's like it, the medallion that they give you is is literal gold, right? Like actual full on gold. And uh they were concerned about the uh the Nazis coming in and being like, give us that, give us that solid gold medallion you've got over there. And so he dissolved it, right? He he kind of put it into a solution.

• 32:35Michael Stevens?

  Uh is it a solution or a colloidal? I don't know.

• 32:37Hannah Fry?

  It's a colloidal, yeah.

• 32:38Michael Stevens?

  But the point is, you look at it, it's just a beaker of gross stuff.

• 32:41Hannah Fry?

  Reddish fluids. You've just got no idea what it is.

• 32:43Michael Stevens?

  Great way to hide gold.

• 32:45Hannah Fry?

  Great way to hide gold. Yeah. They don't go in gold. Also, I just love the idea that it's sort of like created in the, you know, in like the collision of neutron stars and came here on an asteroid, which is admittedly true for almost every heavy element, but.

• 33:00Michael Stevens?

  Yeah, yeah. But, you know, gold was probably also one of the first elements ever discovered, since it can exist in its elemental form.

• 33:10Hannah Fry?

  Yeah. You can spot it in the rocks.

• 33:13Michael Stevens?

  I think sulfur would have been really early because you also can just find sulfur nuggets, veins of sulfur. Whereas carbon, oxygen, it's hard to like see those things if you're just a prehistoric person poking around.

• 33:27Hannah Fry?

  Also, I think it's really entangled with human history, right? Like, we valued it from time immemorial. Like, you know, the first idea of money was like that you would exchange the snugget of gold, you know, even before coins were really a thing. So, okay, there you go, listeners of The Rest Is Science. If you want to send in gifts to either me or Michael, Michael, I'll take as much gold as you want to give me, and Michael will take sulfur.

• 33:51Michael Stevens?

  I really will. But we'll be back next Thursday with another edition of Field Notes. And until then, keep your eyes open, your pencils sharp, and your minds a little bit wild.

• 34:04Hannah Fry?

  And if you have anything you want to send us in, including alternative outros that we can use next week, then please do send them in, [email protected].

• 34:15Michael Stevens?

  Or join our newsletter by heading to restis.com/science.

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