The Device That Maps The Heavens

Tucked away in old engineering kits and museum drawers is a device whose sweeping motion once captivated mathematicians and designers alike. The ellipsograph: a mechanical tool built from sliding arms and rotating joints that were tracing flawless curves long before computers made such things effortless. While they have the appearance of an ancient curiosity, the ellipsograph’s power lies in its ability to transform abstract geometry into tangible motion on a page. Its careful movement can physically enacts the strict mathematical conditions that define an ellipsis - a shape that’s central to geometry, but also to the natural order of the cosmos. So is this object just a relic of the past? Or does it have a place in the present? As a reminder of the deceptive simplicity that rules the world around us, and the ingenuity required to understand it. Welcome to The Rest Is Science: Field Notes. Each Thursday, Hannah and Michael rummage through their personal troves of scientific treasure to source objects that expand our understanding the universe, that scramble our brains, that hint at forces we’ll never see...and, that are sometimes, just plain old 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. ------------------- Find The Rest Is Science all over the internet by ⁠clicking here.⁠ ------------------- Video Producer: Oli Oakley Video & Social: Bex Tyrrell Assistant Producer: Imee Marriott Producer: Becki Hills Senior Producer: Lauren Armstrong-Carter Head Of Digital: Samuel Oakley Exec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:05Hannah Fry?

  This episode is brought to you by Cancer Research UK.

• 0:08Michael Stevens?

  Dinosaurs walked the Earth 180 million years ago. But you know, cancer was part of their story, too. Scientists have found tumors in ancient fossils.

• 0:18Hannah Fry?

  Well, that is a part of the reason why cancer is a big, big part of our story, right? It's the other side of evolution. It's the most complex disease that we face. There are more than 200 types of cancer in total, each with distinct characteristics, challenges and mysteries.

• 0:34Michael Stevens?

  And that complexity demands scale. Cancer Research UK is the world's largest charitable funder of cancer research, with more than 4,000 scientists, doctors and nurses working across more than 20 countries in the search for answers and then sharing their discoveries beyond borders.

• 0:51Hannah Fry?

  And the impact of this collaboration is clear because over the last 50 years, the charity's pioneering work has helped to double cancer survival in the UK. That is more people who are living longer, better lives.

• 1:03Michael Stevens?

  Fossils can show us the past, but research is shaping the future. And for more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit cancerresearchuk.org/restiscience.

• 1:19Speaker 02

  Observe: The North American Dad. 50s, great polo collection. He enters his vehicle information on Carvana. An offer appears in minutes. Remarkable. He squints, reads it again, smiles and says, "Dang, that's a good offer." The highest form of approval. No haggling, no hassle. No one called him "boss." He's still on the couch. Astonishing. Sell your car today on carvana.com. Pickup fees may apply.

• 1:50Speaker 03

  This episode is brought to you by Indeed. You're ready to level up your business, but the pressure to find the right person to make that happen is intense. Indeed sponsored jobs can help carry the load. It boosts your job post to help it reach quality talent fast. Cut through the chaos with Indeed sponsored jobs. Get a $75 sponsored job credit at indeed.com/podcast. Terms and conditions apply. Hiring now? Then this is a job for Indeed sponsored jobs.

• 2:24Michael Stevens?

  Hello and welcome to The Rest Is Science. Today is an episode of Field Notes, where Hannah and I share amazing stories, objects, our deepest fears.

• 2:36Hannah Fry?

  Oh, we're going there today, aren't we?

• 2:37Michael Stevens?

  We might be, or we might not. If you have questions or things you want to share with us, you can always reach out. We would love to take on those. But today Hannah told me that she brought something related to ellipses.

• 2:49Hannah Fry?

  I did. Okay, if you want to draw a circle, easy peasy, get a compass.

• 2:54Michael Stevens?

  Hold on, I want to guess what you brought.

• 2:58Michael Stevens?

  You've already given me a piece of information that's almost confirming what I was gonna guess.

• 3:02Hannah Fry?

  Oh, really? Okay, let's imagine I didn't go.

• 3:03Michael Stevens?

  Okay, is it an ellipsograph?

• 3:05Hannah Fry?

  It might be.

• 3:07Michael Stevens?

  Is it just an ellipsograph? Does it allow me to draw an ellipse? Or does it simply trace an ellipse in a surprising way?

• 3:14Hannah Fry?

  It allows you to draw one, but I think in a surprising way. I think in a very beautiful way.

• 3:22Michael Stevens?

  Is it a circle that rolls on the inside of another circle?

• 3:27Hannah Fry?

  No.

• 3:27Michael Stevens?

  Okay, let's see it.

• 3:30Hannah Fry?

  Okay, you want to draw a circle. You get the compass from your primary school pencil case that you have not opened since and never needed to use in actual, real life. And that's fine, because you just... A circle is a fixed distance from a single point and trace out the arc, right? Easy peasy. Ellipse is way harder, way harder, because instead of having one focus, you have two. And you can do it by putting two pins into a piece of paper and tying a single piece of string between the two, and then using a pencil to trace out that arc. That is one way of doing it. So, some friends of mine at Makers Cabinet have over-engineered a way to draw ellipses. And I thought you might enjoy it.

• 4:12Michael Stevens?

  Yeah.

• 4:12Hannah Fry?

  You know, you're sort of... There's sort of like a draftsman in you somewhere.

• 4:14Michael Stevens?

  Yeah, there is.

• 4:16Hannah Fry?

  The key point here is that an ellipse is a fixed distance between two focai, okay?

• 4:23Hannah Fry?

  Between two points.

• 4:25Michael Stevens?

  So what does that mean? That means that no matter where you are on the ellipse, the combined distance from that point to both foca

• 4:33Hannah Fry?

  is fixed.

• 4:34Michael Stevens?

  Is the same.

• 4:35Hannah Fry?

  Exactly right.

• 4:35Michael Stevens?

  Got it.

• 4:36Hannah Fry?

  Okay, so do you want to have a little play with this? See how you can get it to work?

• 4:39Michael Stevens?

  Okay, okay, so, so there's a magnet. Oh, that's a nice, strong magnet. There's a magnet underneath this page. This sits on it. Ah, yeah, I wanted people to appreciate this ellipsograph. Look at this.

• 4:53Michael Stevens?

  Those shuttles are following straight line tracks. And yet, we trace out an ellipse. From circular motion, well, from, from linear motion, we get circular motion. I love that. It's so well made.

• 5:08Hannah Fry?

  It's beautiful, isn't it?

• 5:08Michael Stevens?

  I've seen them made of wood and plastic, but this is like brass. Look at that.

• 5:14Hannah Fry?

  Isn't that beautiful?

• 5:16Michael Stevens?

  Come on.

• 5:19Michael Stevens?

  What a treat.

• 5:20Hannah Fry?

  I mean, isn't that a treat?

• 5:21Michael Stevens?

  Yeah.

• 5:23Hannah Fry?

  They're the coolest objects.

• 5:25Michael Stevens?

  They're how the planets move.

• 5:26Hannah Fry?

  They are how the planets move. But the thing is that there were such big arguments about the idea that that is how the planets move. Because the Greeks in particular were obsessed with circles. They thought there was like the platonic ideal, the symmetry of it, the beauty of it. It's just absolute perfection. And this stood for a really long time, this idea of circles. I mean, like thousands and thousands of years, people thought it's circles that's going on in the sky. And then Tycho Brahe, or sometimes people say Tycho, don't they?

• 5:53Michael Stevens?

  I say Tycho. I say Tycho Brahe.

• 5:58Hannah Fry?

  From now on, that is how we know. And he was a bit of a bra, actually. He, um, he got into an argument with someone about a formula. Had a duel, ended up losing his nose.

• 6:07Michael Stevens?

  No kidding?

• 6:08Hannah Fry?

  You know this, right?

• 6:09Michael Stevens?

  I didn't know this.

• 6:10Hannah Fry?

  So he lost his nose, so he had a prosthetic nose. He had different ones. He had a bronze one, he had a silver one for special occasions. Um, and then a gold one that flickered in the candlelight to look realistic. But he collected all of these observations of, of celestial objects in the sky. He also had a pet elk. That he um, he used to like bring around to places. In the end, uh, the elk passed away because it got drunk.

• 6:37Michael Stevens?

  Oh no.

• 6:38Hannah Fry?

  Got the elk drunk and um, tried to take it downstairs. Anyway, whatever, he was a bit of a dude, yeah.

• 6:43Michael Stevens?

  This is in like the late fifteen hundreds.

• 6:44Hannah Fry?

  Exactly, exactly, early sixteen hundreds, exactly. And he collected all of these observations and he handed off all of that data to, to his assistant Kepler. And Kepler was like looking for the circles, looking for the circles, trying this circle, that circle. And then eventually came to the conclusion that no, it's not circles, it's ellipses. And he said that it was like a cartload of dung that he had to swallow because he just hated, hated the idea that there might be anything other than circles in the sky.

• 7:16Michael Stevens?

  But it was.

• 7:17Hannah Fry?

  But it was.

• 7:18Michael Stevens?

  And, and swallowing that heap of dung really moved us forward.

• 7:22Hannah Fry?

  It really did.

• 7:22Michael Stevens?

  Imagine that, being like, oh, here's my assistant Kepler. Like, can you imagine BetterHelp? Speaking of the motion of planets, that's perfect because I actually brought something related to them. Now, this shows them in circular orbits, sorry Kepler, but it's a simplified thing for a reason, watch.

• 7:45Michael Stevens?

  This is an orary calendar. It's a page a day calendar. It doesn't tell you an inspirational quote for each day or give you a Sudoku for each day. It shows you the relative positions of the planets each day. So this is January first of twenty twenty six. It's a twenty twenty six calendar. And then the next one is, we got, actually got two of January first. And then, and then the next one is Friday, January second. And as you can see.

• 8:12Hannah Fry?

  Almost imperceptible.

• 8:14Michael Stevens?

  It almost don't change. However, you use it like a flip book and you can see just how quickly the planets are moving in their orbits.

• 8:22Hannah Fry?

  Okay, sure, sure, sure, sure.

• 8:23Michael Stevens?

  Neptune basically doesn't move at all in a year, but Earth goes all the way around once. Now, full disclosure, you can only flip it backwards easily. You kind of have to like break the back.

• 8:36Hannah Fry?

  Oh, that is amazing.

• 8:38Michael Stevens?

  So you can plan ahead and be like, oh, I want to do that thing, but only when Uranus is as far away from Earth as it's going to be all year. And they've got the moon phases on them.

• 8:47Hannah Fry?

  It sort of feels like more than 360 pages, but it isn't.

• 8:50Michael Stevens?

  Well, we made it out of a special recyclable paper, like a compostable paper, because I was like, if we're going to print this many sheets, I want to keep Earth happy.

• 8:58Hannah Fry?

  That is absolutely delightful. Mercury whizzing around there.

• 9:02Michael Stevens?

  I know, isn't it nuts?

• 9:04Hannah Fry?

  And Jupiter just barely, I mean, it's taking its time, isn't it?

• 9:07Michael Stevens?

  Jupiter takes its time to go around the sun, but around its own axis Jupiter is like really fast. Takes the Earth 24 hours to go once around its axis, but it takes Jupiter just 10 hours.

• 9:18Hannah Fry?

  So it's two and a bit days for every day.

• 9:21Michael Stevens?

  That's wild, because Jupiter is huge.

• 9:24Hannah Fry?

  Yeah.

• 9:25Michael Stevens?

  So if you are some gas out on the edge of Jupiter around the equator, you are booking it. Like, no wonder that great red spot won't go away.

• 9:35Michael Stevens?

  The storms on Jupiter have an enormous amount of energy just from that planet whipping it around.

• 9:40Hannah Fry?

  I'm just liking the idea of being on a spaceship and just your face being pulled back with the speed of it.

• 9:44Michael Stevens?

  Well, I mean, it's not quite that fast. I mean, none of us are on Earth being like, whoa, even though we are rotating at, you know, hundreds of miles per hour around its axis, Earth is just too big even for us to appreciate that.

• 9:56Hannah Fry?

  Don't ruin my mentoring.

• 9:57Michael Stevens?

  It does make us a little bit lighter, in the same way that when you're on a spinning carnival ride, you feel like you're, you're being pulled away. Really, you're being pulled tangential to the circle. But on Earth, we are feeling that motion too. And so we weigh a few fractions of a gram less because of its rotation. If it stopped moving, we'd be like, oh, all of the gravity, I'm feeling all of it.

• 10:21Hannah Fry?

  So wait, what's that on Jupiter then? So you're spinning faster, but it is heavier.

• 10:25Michael Stevens?

  You're spinning faster, so you've got an even greater uplift. We often call it a centrifugal force. It's not really a force, but it's that like, whoa, I'm moving away from the center of rotation of my curve. When in reality, you're leaving tangential to the path. But on a big circle, that feels like going straight up.

• 10:46Hannah Fry?

  There's a ride at Thorpe Park. And what's interesting about it is that it has the longest negative G, basically. So you are effectively airborne, if you like, in your seat. But the way that they have to do it, normally you are, as you go on a roller coaster, you are forced into your seat. So you've got to go down.

• 11:07Michael Stevens?

  Right.

• 11:08Hannah Fry?

  Like really feel the weight of it. In this one, it's the opposite. And the way that they do it is they have to slow down the carriage as it goes on the outside of a turn in order for you to really have that feeling of being flung out into the air.

• 11:21Michael Stevens?

  Whoa. I won't be riding on that anytime soon. I don't, no. I just, I never had. As a kid, I actually collected newspaper clippings of deaths on roller coasters.

• 11:34Michael Stevens?

  Because it made me feel like my fear was justified. I still have the box. It's actually the box that my Bill Nye Fan Club subscription goodies came in. And then I just put little comics and recipes and deaths at the Worlds of Fun Theme Park in Kansas City all in there.

• 11:52Hannah Fry?

  Please, one day, can we do a field notes where you go through that box?

• 11:55Michael Stevens?

  Yeah, we sure can. It's going to be a lot of corny Family Circus cartoons that I thought were quite clever when I was eight. But I brought, I brought one more thing. This is actually for your two daughters.

• 12:06Hannah Fry?

  Okay, amazing. You better believe I'm stealing this, by the way, just to be absolutely clear.

• 12:11Michael Stevens?

  You cannot steal that because I have to make a video about it and it's the only one I have. Fine.

• 12:17Michael Stevens?

  I will get you one that can be just yours. Here's two CMY cubes. These are the additions that we put in a curiosity box, as if I'm gonna buy anything for you. But

• 12:28Hannah Fry?

  Rude.

• 12:29Michael Stevens?

  The, the, the couple who invented those are fantastic people and we partnered with them to make this addition of their CMY cube. It is a translucent cube, about two inches on each edge. And opposite faces of the cube have the same color, the same translucent color. And the colors that you'll find are, there's three of them, cyan, magenta, and yellow. CMY. Those are primary colors in the CMY system and you can combine them to make all kinds of other colors.

• 13:03Hannah Fry?

  You've got magenta, then twist it, you've got yellow. And then twist it again and you have got cyan.

• 13:12Michael Stevens?

  Cyan.

• 13:13Hannah Fry?

  I mean, these are the colors you get in your printer.

• 13:14Michael Stevens?

  That's right.

• 13:15Hannah Fry?

  But if you combine them together, hang on, does it work?

• 13:23Hannah Fry?

  Does it work?

• 13:24Michael Stevens?

  It does work, yeah.

• 13:26Hannah Fry?

  I'm just trying to work out what the colors would be.

• 13:27Michael Stevens?

  It can be very confusing because there's not just the subtractive color mixing that's happening, there's also reflection. But greens and purples and oranges are produced as the light is subtractively changed. Passing through the cyan filter, only cyan comes through.

• 13:45Hannah Fry?

  Hey, um, do you know where you send naughty rainbows?

• 13:49Michael Stevens?

  Where?

• 13:49Hannah Fry?

  To Prism.

• 13:56Michael Stevens?

  I do, I do like that Prisms can create rainbows, but they can also destroy them. If you send a Prism through a rainbow, it comes out as white light.

• 14:04Hannah Fry?

  Does it?

• 14:05Michael Stevens?

  Yeah. And if you look at a rainbow, like a rainbow in a children's book through a Prism, at the right distance, it'll get smashed into just a white line. Yeah.

• 14:14Hannah Fry?

  These are absolutely amazing.

• 14:15Michael Stevens?

  They're really beautiful.

• 14:16Hannah Fry?

  Really beautiful.

• 14:16Michael Stevens?

  And they're really well made.

• 14:18Hannah Fry?

  Also, what I notice is, like the source of truth, this is the second object that you've given me for my children with extremely sharp edges.

• 14:26Michael Stevens?

  Oh, that's right. Yeah. You're welcome.

• 14:31Hannah Fry?

  Amazing. Shall we go to break?

• 14:32Michael Stevens?

  Let's take a break.

• 14:39Speaker 03

  This episode is brought to you by Indeed. You're ready to level up your business, but the pressure to find the right person to make that happen is intense. Indeed sponsored jobs can help carry the load. It boosts your job post to help it reach quality talent fast. Cut through the chaos with Indeed sponsored jobs. Get a $75 sponsored job credit at indeed.com/podcast. Terms and conditions apply. Hiring now? Then this is a job for Indeed sponsored jobs.

• 15:10Speaker 04

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• 15:44Hannah Fry?

  Welcome back. This is Field Notes, an extra half an hour that you get to spend in the company of me and Michael every single week, where we try and impress each other with things that we know, things that we've found.

• 15:53Michael Stevens?

  I'm not trying to impress you with any of this.

• 15:55Hannah Fry?

  Oh, I'm absolutely trying to impress you.

• 15:57Michael Stevens?

  I'm trying to impress my mom.

• 16:00Hannah Fry?

  Yeah, aren't we all?

• 16:02Michael Stevens?

  Anyway, sorry, this got really...

• 16:04Hannah Fry?

  Deep.

• 16:06Michael Stevens?

  Deep, very quickly. Let's lighten it up. Who's got a question?

• 16:10Hannah Fry?

  Shall we go to the mailbag?

• 16:11Michael Stevens?

  Yeah.

• 16:12Hannah Fry?

  Okay, all right. We've got some interesting questions this week. By the way, please do feel free to send in your questions to [email protected]. All right, Alana asks, "You can invite three other people from the world of science who are dead or alive to a dinner party. Who are you choosing?"

• 16:29Michael Stevens?

  Oh my gosh. Do you have an answer?

• 16:33Hannah Fry?

  I mean, I've definitely got some favorites.

• 16:35Michael Stevens?

  Yeah, sure, sure, sure. I feel like, you know, Albert Einstein is one of the more obvious cliche types of answers, but I want to know what his last words were. You know, he spoke them in German to a nurse who did not know German. And so they've been lost.

• 16:51Hannah Fry?

  No.

• 16:52Michael Stevens?

  I want to know if it was like, oh crap. Or if it was like, oh, it's actually MC cube, you know, or something. Uh, I don't know, but I would love to find out.

• 17:04Hannah Fry?

  I'd also like to know how he feels about, do you know the story about Einstein's brain?

• 17:07Michael Stevens?

  Oh, his brain?

• 17:08Hannah Fry?

  Yeah. It, yes, and then it was sort of extracted, put in a jar and then just forgotten about.

• 17:14Michael Stevens?

  That's right.

• 17:15Hannah Fry?

  It was in the back of a cupboard and someone found it years later and were like, why is this? And it turned out to be Einstein's brain.

• 17:21Michael Stevens?

  Einstein's brain, and this was at like a medical facility, by the way. It wasn't just like, oh, his neighbors came over and pulled it out.

• 17:27Hannah Fry?

  In the garden.

• 17:28Michael Stevens?

  It was like donated to be studied and then.

• 17:31Hannah Fry?

  Just forgotten about.

• 17:31Michael Stevens?

  Forgotten about.

• 17:32Hannah Fry?

  Yeah.

• 17:32Michael Stevens?

  In a little medical closet.

• 17:34Hannah Fry?

  But when they did study it, they, they, they basically found there was nothing remarkable about it, right? It's like maybe slightly more white matter than, than the rest of us.

• 17:41Michael Stevens?

  Okay.

• 17:41Hannah Fry?

  I'd like to ask him about that. I would like to ask him about that. How do you feel about your brain being forgotten about in a, in a cupboard for a very long time?

• 17:48Michael Stevens?

  Okay, so besides Einstein, who's on your list?

• 17:50Hannah Fry?

  Okay, I would quite like to meet Galois.

• 17:54Michael Stevens?

  Who is that?

• 17:55Hannah Fry?

  Okay, so Galois is like, he's such a dude. He's this French mathematician. He's like nineteen, twenty years old and he is super, super, super bright. But he's also very French. And loves to have affairs with beautiful women. One of the people he has an affair with, uh, turns out to be engaged to some very important soldier in the town, who challenges him to a duel. And of course, because he is very French and this is, you know, around seventeen hundreds, you can't turn down a duel. So he agrees to go off and have the duel, have the fight with this, you know, with with his lover's partner. Before he does that, he decides he needs to finish his maths theory.

• 18:39Michael Stevens?

  Okay.

• 18:39Hannah Fry?

  So he stays up all night and he scribbles this stuff down. It's all about, you know, you have quadratics, which is where you have, where you have something squared.

• 18:48Michael Stevens?

  Yeah.

• 18:49Hannah Fry?

  You have cubics, which is, which is cubed to the power of three. But he was looking at quartics and quintics.

• 18:55Michael Stevens?

  Wow.

• 18:55Hannah Fry?

  Equations to the power of five, right? I'll be honest with you, it gets very hard very quickly.

• 18:59Michael Stevens?

  Yeah.

• 19:00Hannah Fry?

  Um, but so he's, he's there, he's like, I've got to, I've got to work out these equations, I've got to work out these equations. And we still have the kind of ink splattered pages that he wrote on that night. Every now and then he's like, he's scribbling down the theory, he's crossing stuff out and then he writes like, la femme, la femme. And then he's like, oh, I'm gonna die in the morning. It's like, no, I've got to get back to these equations. Anyway, he goes off, he does the duel, he loses in the duel, loses his life. But those pages and the work that he did in advance of that then goes on to be absolutely foundational. And now every person who goes to study mathematics as a degree level will learn Galois theory. This twenty year old kid, what a romantic story that is.

• 19:39Michael Stevens?

  Wow, it's like, if he'd been given just a couple more days, what else could he have discovered? Or was it the impending possibility of death that made him work so well? It just spilled off all that brilliance at once.

• 19:51Hannah Fry?

  I'd just like to, to meet him at dinner and be like, you idiot. You idiot.

• 19:58Michael Stevens?

  That would be very cool. Can we go to the same dinner party together?

• 20:01Hannah Fry?

  Okay. So we've got Einstein and Galois.

• 20:03Michael Stevens?

  We could go, we could go way back in time, like I'm thinking about a Pythagoras would be neat. Uh, this is sort of the world of math at this point, but like, I want to hear about the, the meaning of numbers to him. What do they mean to you? It was much more religious.

• 20:17Hannah Fry?

  He didn't really like numbers. I mean, they didn't really like numbers at all, the Griggs.

• 20:21Michael Stevens?

  Not all of them.

• 20:22Hannah Fry?

  Sure.

• 20:23Michael Stevens?

  Those irrational ones.

• 20:24Hannah Fry?

  Those irrational ones, they weren't so happy with.

• 20:27Michael Stevens?

  They were like the demons. Obviously Archimedes. I think it'd be cool just to say that I met him. I love that of all the things Archimedes did, the inventions, the eureka, I'm in a bathtub and I've learned about volume and how to measure it. The story goes that on his gravestone, do you know what he had them put there?

• 20:48Hannah Fry?

  Go on.

• 20:49Michael Stevens?

  A sphere, a cylinder and a cone of equal heights. Because he showed the relationships between their volumes and he was so proud of that, that he was like, of everything I did, I want that to be what's on my grave.

• 21:03Hannah Fry?

  Is Archimedes the one who died at the hand of a soldier who was trying to capture him? I think that there was some sort of invasion of his island and then he was told to, because he was such a genius, they were like gonna capture him and bring him back to the whatever, king.

• 21:19Michael Stevens?

  Okay.

• 21:20Hannah Fry?

  Something. The soldier went in and was like, you need to come with me. And he was like, don't disturb me when I'm with my circles. And so the soldier killed him.

• 21:28Michael Stevens?

  Wow.

• 21:29Hannah Fry?

  Yeah.

• 21:30Michael Stevens?

  For the circles.

• 21:31Hannah Fry?

  For the circles.

• 21:31Michael Stevens?

  He just couldn't give them up.

• 21:32Hannah Fry?

  Yeah. Maybe, maybe instead of doing like, maybe instead of picking people based on the interesting things they have to offer, maybe we should just get the people who've got the most stupid deaths in science.

• 21:42Michael Stevens?

  Yeah, right. And we can just make fun of them.

• 21:44Hannah Fry?

  Just make fun of them.

• 21:44Michael Stevens?

  You could bring Archimedes and then have a bunch of circle foods, okay? Slices of baloney, pie, pizzas.

• 21:52Hannah Fry?

  Yeah.

• 21:52Michael Stevens?

  And be like, hey, let's cut them up, let's make some cords, some diameters.

• 21:56Hannah Fry?

  In your honor, in your honor. Here is this, here's a cone shaped cake.

• 22:00Michael Stevens?

  So yeah, it's not so much to learn from them, but it's to honor them and kinda razz them a bit.

• 22:05Hannah Fry?

  Yeah, I'd be up for that. That sounds like a good dinner party. Actually Pythagoras himself, he's got an amazing death. Do you know about Pythagoras's death?

• 22:12Michael Stevens?

  No.

• 22:12Hannah Fry?

  Okay, so, I mean, this is possibly apocryphal, but I'll be honest with you.

• 22:16Michael Stevens?

  A lot of stories that old are.

• 22:18Hannah Fry?

  Sure.

• 22:18Michael Stevens?

  Yeah.

• 22:19Hannah Fry?

  Right, Pythagoras, of triangle fame, absolutely amazing, had a school, basically like had loads of, you know, disciples. Terrified of beans, really, really hated them, thought that they looked like sort of miniature humans, just really, he absolutely appalled them.

• 22:33Michael Stevens?

  Yeah, who hasn't thought that? What?

• 22:36Hannah Fry?

  He hasn't thought that. Beans were banned in his school.

• 22:38Michael Stevens?

  Okay, got it.

• 22:39Hannah Fry?

  And the rumor goes that he had sort of a fight with some other people. They wanted to join his school, he didn't let them. They barricaded his house, set it on fire, and he ran away, managed to get free, ran away. And they were chasing him, and then he carried on running, and it was all fine until he came up to a field of beans. And he refused to run through the field of beans, and so they caught up with him and killed him.

• 23:00Michael Stevens?

  Wow.

• 23:01Hannah Fry?

  That sounds like a great dinner party. Beans and pizza for dinner.

• 23:05Michael Stevens?

  Would you bring beans? Yeah.

• 23:08Hannah Fry?

  Would you not bring beans?

• 23:09Michael Stevens?

  Bean pizza, bean cookies, like a can of refried beans is a cylinder.

• 23:15Hannah Fry?

  Mmm.

• 23:16Michael Stevens?

  Archimedes would love that, Pythagoras wouldn't, but you know, he's got a, he's got a lot of credit. It's time for him to get a little.

• 23:23Hannah Fry?

  Roasting.

• 23:24Michael Stevens?

  Roasting, that's right, that's right. Well, we've got one more question. This one is from Fred. Fred asks, why do goldfish have such short memories?

• 23:33Hannah Fry?

  Okay, I think that this is a massive misconception.

• 23:36Michael Stevens?

  I was wondering if that might be, yeah.

• 23:38Hannah Fry?

  I think that actually there have been experiments with goldfish where they can sort of, you know, be shown to navigate, amazed to get food, and then can remember the route that they've learned months afterwards.

• 23:50Michael Stevens?

  So where did this misconception start?

• 23:52Hannah Fry?

  I think it's just snobbery.

• 23:54Michael Stevens?

  Right.

• 23:54Hannah Fry?

  I think it's just straight up snobbery. But also, it really does, I think, underline the cruelty of putting a goldfish in a bowl where it's got nothing to do. Because of course, if it's only got a three second memory, who cares that it doesn't have anything to interact with? But I mean, we did an episode about boredom. All this time, those pretty little goldfish that we've been having to effectively decorate our homes, we've been essentially torturing them.

• 24:19Michael Stevens?

  Yeah, I don't know what kind of space they need, but yeah, a three second memory seems pretty made up. Maybe to make us feel better about like, oh yeah, there's not much to do there. But yeah, I don't know how much room they need. They might even need like a place where they feel like they can go to be safe and hidden, like a little, you know, rock cave feature.

• 24:37Hannah Fry?

  Maybe a goldfish friend?

• 24:38Michael Stevens?

  A goldfish friend?

• 24:39Hannah Fry?

  Yeah.

• 24:40Michael Stevens?

  Do they like having friends?

• 24:41Hannah Fry?

  I think they do, I think they are quite sociable.

• 24:43Michael Stevens?

  Yeah.

• 24:43Hannah Fry?

  Yeah. I've never owned one, have you?

• 24:45Michael Stevens?

  I might have had one when I was like four, because I kind of remember fish. But not since then. My daughter really wants a bird.

• 24:55Hannah Fry?

  Oh, yeah.

• 24:55Michael Stevens?

  And I'm like, birds deserve to be free. Not gonna happen.

• 24:59Hannah Fry?

  So I had a cockatiel when I was younger. What was interesting about him is he would sit on your shoulder in the garden.

• 25:05Michael Stevens?

  Oh, outdoors.

• 25:06Hannah Fry?

  Yeah.

• 25:06Michael Stevens?

  And not leave.

• 25:07Hannah Fry?

  And not leave. I think you can bond with a bird. I think that's my point. I think you can bond with a bird.

• 25:11Michael Stevens?

  I believe that for sure, for sure. And you guys can bond with us by joining our newsletter at the rest is science at goalhanger.com.

• 25:29Speaker 05

  There we are getting a statement from Number 10 on that flight with 350 passengers on board.

• 25:38Speaker 06

  The Great Game, strategic struggle between Britain and Russia.

• 25:45Speaker 07

  We assess, uh, Prime Minister, with high confidence, it was Russian.

• 25:52Speaker 02

  Holding the Russians accountable is World War III.

• 25:54Hannah Fry?

  They took down a British passenger jet containing 350 people.

• 25:57Speaker 06

  Man in the Kremlin is playing, Alex. Got to ask yourself, you want to play or not? You're the Prime Minister. You've done nothing!

• 26:10Speaker 02

  We would need to understand the policy context.

• 26:12Speaker 06

  All the relevant context will be structured as a framework today and disseminated into an operation order or FROGO.

• 26:21Speaker 08

  A FROGO that says to kill the President of Russia?

• 26:26Speaker 06

  Yes.

• 26:28Speaker 08

  New from Goalhanger. Who is going to be able to pull this off first?

• 26:32Speaker 09

  You're my soldier, are you? Sergeant Tom McDuff, Duffy!

• 26:36Speaker 08

  An audio drama journey like no other.

• 26:38Speaker 09

  Men like Duffy, they are our most valuable weapons.

• 26:42Speaker 08

  Devized as a technically rigorous geopolitical action thriller. Where Britain plays its strongest arm. He's the best. Against its strongest foe. Don't do it, Duffy!

• 26:55Speaker 08

  Bear Hunt.

• 26:57Speaker 08

  Available now wherever you get your podcasts.