The Rest Is Science - Why Erdős Was The Original Kevin Bacon

Episode Date: January 15, 2026

Some objects feel like they’re from another world. One of these might be the giant structure that makes up a quantum computer. Lifted straight from the TV series Devs, Professor Hannah Fry shows Michael Stevens a prop that was designed to look just like one…now it hangs from the ceiling in her house. In this episode of Field Notes, Hannah and Michael examine the extraordinary technology behind of quantum computing. They explore how qubits differ from classical bits and consider the ways this technology could reshape our world, from encryption to drug discovery. Answering your questions, they also look at the eccentric mathematician Paul Erdős and discover what Erdős and Kevin Bacon have in common. Welcome to The Rest Is Science: Field Notes. Every Thursday, Hannah and Michael rummage through their personal troves of scientific treasure, sharing discoveries that reveal the hidden forces shaping our universe, the objects that bend our brains, and a few things that are just plain incredible. They’ll also be tackling your questions, so email The Rest Is Science at [e-mail]. ------------------- 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 Learn more about your ad choices. Visit podcastchoices.com/adchoices

This episode is brought to you by Cancer Research, UK. Dinosaurs walked the earth 180 million years ago. But as you know, cancer was part of their story too. Scientists have found tumors in ancient fossils. Well, that is 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.

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. 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. 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 canacerreseachuk.org forward slash rest is science. Welcome to the rest of science. This is field notes. It's a sort of podcast expedition, if you will, where Michael and I are going to trade curious objects or things that have been occupying our minds. Yeah, that's right. Every week we're going to bring something from our little, you know, the mystery bags of our lives to share with the other and with you. I mean, put it this way, Michael and I are massive nerds and always have been.

So over the years, we've collected all manner of bonkers and bananas, objects and ideas. And that's, I mean, we've got at least seven to eight years worth of stuff to go through, Michael, I reckon, in terms of episodes. Yeah, right? And it's even more than that, because we want things from you guys. So send in your questions and ideas to where? Well, I know. It's the rest is science at gollhanger.com. What a great email address. Yeah, you would think that by now we would remember it.

But no, it still remains a difficulty for us. Later on in this episode, I'm going to be showing you the ultimate nerd trophy. It's the most remarkable and weird thing that I own. Oh. That's coming up in our episode. But first, some questions from you. That's right. From you guys who are out there listening, not from me.

I will read this one to you, though, Hannah. is a question from Haley, who asks, who is or was, in your opinion, the scientist with the most peculiar personality? Most peculiar personality. I mean, there's a lot of, there's a lot of people who could be in that category. It's like all of them. Like you have to be peculiar to, well, we're all peculiar in some way. Some of us more peculiar than others. It definitely helps, doesn't it? I think if you're willing to completely dedicate your entire life to advancing human knowledge by just the smallest, smallest amount, no guarantee of success, then I think there usually does have to be something a little bit peculiar about it. I mean, mathematicians, I think,

are often right up there with the most peculiar of all. I mean, there's Cantor who discovered that infinities can be different sizes. I mean, that in itself is a wild idea. But he at one point thought that he was causing the rain by staring his own urine. So, I mean, there's a lot of... Wait, really? Yeah. Oh, that's incredible. See, I don't know anything about him outside of the mathematics that he worked on.

I'm going to write that down because I love examples of things like Isaac Newton believing that the world was going to end on a specific date and all the esoteric work that he did. D.H. Lawrence, the author, believed that the moon produced its own light. Oh. And it's just kind of surprising when you're like, oh, yeah. It was easier to believe that confidently back then. Yeah, absolutely was. I think number one, though, number one for me is going to go to Erdos.

Is that the six degrees of Kevin Bacon mathematician? It absolutely is the six degrees of Kevin Bacon mathematician. Okay, explain what that is to our listeners. Okay, so he did a lot of work on graph theory, which it's not about graphs as in X and Y axis, it's graphs as in networks. That's what mathematicians call them. But he also was a sort of lived example of this.

he published an incredible number of papers, but in particular he published with a lot of co-authors. And what he would do, actually, he didn't have a house, right? He didn't sort of, he didn't have a kind of traditional life. What he would do is he would rock up at different mathematicians' houses and then turn up and say, my brain is open and sleep on their couch where they would take on the responsibility for cleaning him, feeding him, laundering his...

Actually, he didn't do laundry, he chucked his clothes away once he'd worn. them, not because he was ostentatious and rich, just because he didn't care for such things. But while he was there, he would write papers with them. But what it then meant is that over time, he had collaborated with such an unbelievable number of people that people came up with the idea of an Erdos number, which is how many steps away in a network you are from having collaborated directly with Erdos the man himself. So not only a lot of collaborators, but it sounds like also a very diverse variety of types of papers in mathematics. Yeah, absolutely. And this, I think this is the one that is the most famous idea. So the

bacon number is analogous, but the idea is that Kevin Bacon has been in so many different films with so many different people that, uh, if, that you can have a bacon number to. So you, if you have a bacon number of zero, you are Kevin Bacon himself. If you have a bacon number of one, you have appeared on screen with Kevin Bacon. And a, uh, a bacon number of two and you have appeared on screen with somebody who has appeared on screen with Kevin Bacon and so on and so on and so on. If you have an Erdos number of zero, you are. You are.

Yeah. Which, by the way, until you said it, I thought it was Erdos. Oh. So that's why it's helpful to do audio programs about mathematicians, Erdash. I think I've found an Erdosch number of four, by the way. I think mine is four. That's yours is four. I think so, yeah.

Let me just double check. No, we haven't published a paper together, which is like the rule, right? But if we did, I would have a number of five. Absolutely. But we have appeared on screen together. What's your bacon number? I don't know. Is there a way to find out?

I don't, I haven't really been in enough, like, IMDB type shows. Oh, it's five. My Erdos number is five. Oh, okay. Oh, hold on. I've got a bacon number of three. How? I've only done one thing ever where.

which was drama. But I appeared on screen with Lenny Rush, who is this absolutely amazing actor. He has a bacon number of two. So there we go. I've got an Erdosh Bacon number of 5'2. But that means you're 6 3 at the very least. You think?

I have a bacon of 6. Airdosh of 6. We have to publish something together. But after that. Well, should we come up with a name for the bacon Erdash ratio? Yeah, go on. Oh, oh my gosh. There's an Erdash Bay.

It measures the collaborative distance in authoring papers between that person and Erdash and their bacon number. Oh, no. Go on. It doesn't have a funny name. It's just called the Erdash Bacon number. And the lowest is three. Mathematician Daniel Clayton has an Erdash Bacon number of three because he co-authored papers with Erdash and has a bacon number of two because he appeared as an extra in Goodwill Hunting with Minnie Driver who appeared with bacon in sleepers. Yeah, that is impressive.

So what was his three? Mine seven. Pathetic. Pathetic. I need to hunt down Kevin Bacon immediately. Right. I mean, yeah. So, so, so, so you could probably collaborate with someone who worked with Erdash directly. Yeah, not not, I mean, I haven't got long to go because this is, this is, you know, he was around in sort of the, he was particularly big in the 1960s. Yeah, you got to do it now, but you could achieve what at most today, a Erdash number of two. Yeah. And then Bacon is still alive. That can become a one. So you could beat Daniel Klightman You could equal him, no? Two and one, three.

Yeah, you add him together. So the best you could do would be to tie him. Records that can't be broken, Michael, one of your favorite subjects. Wow, okay, yet another tab I'm not going to be closing. How many are there out of interest? Let's see if I can figure that out. There's too many for me to easily navigate, but on this one window,

I have. It's over a hundred. Can I tell you why I pick Erdos, right, as the most peculiar person? Because I mean, the Erdos breaking stuff is all very nice, but what makes Erdos peculiar, apart from the fact that he didn't have a house and just turned up at his friend's

doors insisting that they take care of him? He also took a lot of amphetamines and some people were concerned that he was addicted to them. He was working like 19 hours a day. And so a friend of his, Ron Graham, bet him $500 that he he wasn't able to stop

taking the drugs, right? You couldn't go cold turkey for 30 days. And so Edda's was like, fine, I'll do it. So he stopped, he immediately stopped. He took the $500 from Graham and didn't touch the drugs at all in that time. And then at the end he said, look, see, what you've

proved is you've proved that I'm not an addict, so well done you, but what you've done here is you've set mathematics back by a month. Because he needed the drugs to do math. And he knew the drugs to do the math, which I quite like. The other thing about him is that he, my favorite story about him, is that he was totally incapable of feeding himself, right? Just didn't understand the most basic ideas of how to construct a sandwich, for instance.

So there was one day where he was staying at a friend's house and he was hungry. He went into the kitchen, probably because of all of their amphetamine, went into the kitchen, opened the fridge and found a part of tomato juice. Couldn't work out how to open it. So got a knife from the counter. stabbed it open tomato juice went everywhere drank from the carton

left it on the side and then went off back to work and his friend came down just to witness what looked like a murder scene in his kitchen just like that's just erdos

that's just erdos that's just erdosh that's just erdosh there he is I mean that sounds like something I might do in college not saying I'm Erdashi

but I get it I get it yeah fair yeah what nice, I mean, what a great guy. He also, he thought that God was the supreme fascist. And he would, he would regularly attribute every time he lost his glasses or, you know, couldn't find a book that he wanted to read or whatever, he would be like, it was the supreme fascist that did that. But when he found a really beautiful mathematical proof that was, that

couldn't be approved upon, that was essentially perfection, he said, look, that came from the book. And the book was the supreme fascist's little handbook of perfect mathematical. proofs that could only even have been created by God. Oh, so it's like a bittersweet Supreme Fascist. A bittersweet Supreme Fascist. That's a sentence I think that has not ever been spoken before and probably never will be again. Good. This is a great question.

It's from Francisco from Lisbon. Would it be possible to explain to a humanoid alien, bilaterally symmetrical, via written or spoken message, no direct or visual contact, which side is left and which is right, the alien would have no access to anything on Earth or a human body as a reference, nor would they be really aware of North and South. Is there a fundamental physical or cosmological real world difference between left and right? And can that information be passed on? Great question, Francisco. Oh my gosh. Yes, I love this because I got really obsessed with it years ago. I read Martin Gardner's Amidextrous Universe, which I recommend to everyone. It is a book all about mirror images, symmetries. He poses that same question and goes through all the

ways we can't answer it. And so I read the whole book thinking, we still don't know the answer. And I'm like, I'm going to make a video about this. It's such a deep mystery. And then at the end, he's like, oh, and then in 1956, we figured it out. So to kind of like lay the scene, I think it's good to imagine communicating with aliens through, say, radio waves only, so we can't send images, and we're trying to tell them how to build something that

is an adiomorphic, like a coffee cup, a Father's Day number one dad coffee cup. All right, so you tell them, all right, this is easy. You make a cylinder. Fine. They know what a cylinder is, right? There are symmetries in our universe that make

something we can easily explain. We can talk about points and whatever. Now we tell them, like, take off the top and empty the volume inside, but leave one side at the bottom. And now they've made a cup. And then you tell them print number one dad so that when you look at it, you see it. And they're like, yeah, we're following. And they're doing this. And now you tell them you've got to put a handle on it.

And you say, now the handle should go since, you know, here on earth, most people are right-handed. We tend to put the handles on the right side. So when you hold it, you see the printing. And they go, which one's the right? side. Think about it. This is much harder than you might imagine. Remember, we cannot reference anything in the environment. You can't say, look at number one dad on the mug, look at Earth, and the Virgo supercluster is to the right. You can't do that. If you're not allowed to do that, what do you tell them to differentiate left and right? Because you could say, you could say,

okay, place the handle along the axis of the cylinder so that it's perpendicular to the base. That would be fine. And then you could say, and now rotate it so that, the handle, so it's no longer symmetrical about the central line. That would be fine. But distinguishing left from right, really hard. Yes, because we could tell them to, you know, looking at the handle, rotate the mug, but rotate which way. Which way is right and which is left?

And how do we tell them with words alone and no references to any other models we've ever since, at least Kant people wrote about how, golly. It doesn't make any sense. Like a right hand floating in a universe all on its own doesn't have a rightness or a leftness. So for decades, we thought maybe there wasn't an answer because of the four fundamental forces, three of them we knew made no difference when mirror reversed.

Left and right didn't matter. So gravity, electromagnetism, and the strong nuclear force make no distinction. If you watch them do things in a mirror, it all looks fine, right? You look at a pendulum in a mirror, it's obeying all the normal physics, and it fits all the normal formula and equations.

So this was true for these three fundamental forces, but the weak force was hypothesized to not have that same symmetry. And an experiment was devised that essentially looked at the spin of electrons emitted by a decaying cobalt 60. This is called the Wu experiment. So in the Wu experiment,

They use cobalt 60 atoms that are decaying, and they put them into both, let's call it, regular spin orientations and mirror image spin orientations, and found that the electrons that decayed out came out in the same direction. It's not like, okay, you spin this way, the electrons come up, and you spin the other way, and they come down, in which case, then it's, you can't really know. You just reverse it and it's the same. Instead, they found it didn't matter. The electrons always came out in one direction. So that can be called, you know, your left or right, whichever it is. I don't know enough about Cobalt. But that is a way to agree because you'll both see the same thing.

So, okay, let me make sure I understand this then. Right. So you get the mug. You're like, you've got number one to add on it. And then the only way to distinguish left and right as innate properties of the universe rather than just some sort of convention that we have decided on, is to get subatomic particles, perform these experiments where you are, looking at the spin, looking at the direction of the electrons,

and then that's the way that they can print the handle on the rise. I would say it doesn't matter if they print it on the left-hand side. I think it would probably be all right. I think if we want them to match, we have to do all of that rigmarole. And that is such a cool feature of our universe, because it is otherwise so simple, left and right? Come on. You know, it's, it's, it's, it's right there. And yet it isn't, except the weak force comes in clutch at the end and says, all right, guys, technically, if you're willing to do a lot of work, I can help. There is something really nice about this idea that there are directions. I mean, time is the other one, right? Time faces only in one direction. You know, you can't go backwards in time. There's something really nice about this idea that these fundamental rules of physics.

Maybe I don't think about this deeply enough, but couldn't you just say, all right, you've got some electrons going through a wire? Those electrons are going in, say, one particular direction, and they will create a magnetic field that wraps around the wire. I mean, that's the right-hand rule, right? Could you not say that it wrapped around clockwise, anti-clockwise? I don't know. Is there not a way to get it that way? Yes. Yes, there is not a way to do it that way, and I unfortunately do not know why.

I think it has something to do with you need to both agree on which is the north side of a magnet first. Oh. It's something like that. Now, we've since learned that you can use other things besides cobalt. You can use uranium 239. You know, that might help us if the aliens are like, ooh, we don't have any cobalt. But still, it's a lot of work. So then if you get the mug to bring the mug in, you say, all right, whichever way that your electron goes off in,

orient the mug, so that you... that the axis of or the the wording of the number one dad is in parallel to that and then perpendicular whatever. I mean, that's the way that you do it. That's the way you would have to do it. Yeah. Wow. Extraordinary. Extraordinary. By the way, this is my dream Father's Day gift. I want my daughter to get me a number 2,587,312 dad. Why specifically that number? I just feel like that's probably where I am, you know? Like, I'm not the number one dad. There can't be more than one number one, number one, but that's all they sell, number one dad mugs. I want to have a reasonable I'm probably like, you know, top, top 30% maybe. Like, put me there. Make it act like I

actually earned this. Anyway, that's the gift that I want. But after the break, Hannah, you've got a gift for me. It's a treat. Buckle up. This episode is brought to you by Cancer Research. You can. We often think of beating cancer as treatment, but imagine stopping it before it begins. After years of work, Cancer Research UK scientists are launching a clinical trial of lung vax, the first vaccine designed to prevent lung cancer. It builds on TracerX, the world's largest cancer evolution study, which tracked lung cancer cells over many years to uncover the disease's earliest warning signs.

Lung Vax is designed to train the immune system to spot the... signs early on, destroying 40 cells before cancer develops. So it's not treatment, but preventative, with the potential to stop lung cancer before it starts. The first stage of the trial starts this year focusing on people at higher risk. It shows what long-term research makes possible. For more information about Cancer Research UK, their research breakthroughs and how you can support them, visit cancer research UK.org forward slash the rest is science. Welcome back from the break. I've been saving this one, Michael. This is this is by quite a long stretch the best thing I own. It's also the most ridiculous thing I own.

So, you know, don't judge my entire character based on this. I will. I'm going to. Okay. It's as I described it earlier on, the ultimate nerd trophy. Okay, so there is a science fiction director called Alex Garland. He wrote The Beach he directed X. Macanard's really amazing film about the sort of future of humanity with artificial intelligence embedded in it. He also did this amazing HBO show called Devs, which was about a sentient quantum computer that was able to calculate the position of every atom in the entire universe and thus all of the future and the past was available to it. Oh, like Laplace's demon.

Exactly. Laplace's demon, this theory. theoretical construct that was based on the idea that if the universe is deterministic, then every single thing should be predictable. The only problem is we don't know where all the atoms are. And that's the thing that's stopping us knowing every single thing. So this is the central idea of this show. Now, as part of the show, they made a quantum computer, or at least a prop that looked like a quantum computer.

And what they made was this very beautiful thing. Ooh, yeah. Very beautiful prop that was made for the show. Yes. This is designed to be an accurate representation of what you really see from quantum computers. So what we're looking at here is like the Tower of Babel but upside down. Like an upside down tiered cake, but without the cake, just the tiers. A series of platforms like circular disks connected one below the other by thin rods

with a big collection of very thin, very ultra-fine, wide. coming out, but arranged very neatly. Like they've just been so precisely combed and gelled into this arrangement. It's almost like lit from inside as well. Very gold and everywhere. Gold and silver are the big notes of color. It's very blingy, isn't it? It's very blingy, but very like delicate, like a fish skeleton.

These very thin bones arranged so purposefully. So they are indeed made with this incredible amount. of gold, all of this wiring, this is all very accurate. I mean, it's sort of like slightly fancified for the purposes of production. If you've seen photographs of quantum computers, that is exactly what they look like. These great golden structures with wires all over the place. They're very beautiful. Would make, I think, a very nice chandelier.

Yes. That's what I think about it. That's what it looks like. That is exactly what looks like. Very beautiful. Anyway, so they made this show. and a little while after it was made, they still had this beautiful prop.

The problem was that after they finished filming, they had this object in a storage unit. And it was... How big was it? It's hard for you get into its scale. Big. We're talking sort of from top to bottom, maybe 10 feet. Oh, wow.

Okay. Right. Giant. Okay. So they have these giant crates, this big storage unit, and these storage units were costing an absolute fortune. Yeah.

So a couple of years after, after production ended, Alex Garland and his team were, they were like, we don't want to throw it away. We spent an absolute fortune making this incredibly beautiful model of a quantum computer. So they were ringing around the different museums and places which might take it. And it just so happened at the time I was doing up my house. And I have in my house this big sort of hole that's cut in the floor, kind of a big void.

And I was looking, I just so happened to be looking at that moment. moment in time for something that I could hang in that void. And so I basically rescued it out for Skip. So it's hanging from the ceiling. It's hanging from the ceiling. Oh, like a big chandelier. Like a giant chandelier. Oh, Hannah, that is incredible.

No, isn't it? I mean, you can, Michael can see the picture of my house and he can confirm that my house is not massive. It basically takes up quite a lot of my house. Every time someone, I mean, the postman comes in, you can see it from inside the front door. They wonder what it is, because it's. sort of looks like a spaceship if I accidentally leave the curtains.

Yeah, I mean, it can pass as a chandelier, as a piece of artwork. How is it lit up? Is that the way it was lit up in the movie, or did you have to add the lighting, the bulbs? The light panels were in there from the movie. Real quantum computers, by the way, do not have a light. This you can see sort of like a scan of it in position. We replaced the LED so that they could be, they would last much longer. Also, what I did is I've made it so they're each individually

controlled. So I have put a little computer in there, Bluetooth, that's connected via Bluetooth. And one of my projects for a summer when I have some time off, what I want to do is program it so that when I play music in the house, the quantum computer sort of twinkles in time. Visualizes the music. Exactly right. But what I really wanted to do, I wanted to show you this image because I sort of actually wanted to talk a little bit about the way that these things work. Okay, but first of all, I'm sorry. How did you get it? Did you reach out to them?

No. So I have a, my very good friend, Adam Rutherford, is, was the scientific advisor on the series and is a very good friend of Alex Garland's. But I just so happened to be in the right room when they were like, we're going to have to throw it away. We're going to have to basically sell it for scrap because nobody wants it. The museums didn't want it because it wasn't a real quantum computer. Yeah. I mean, where else would you put it? You know, who would be crazy enough to have one of them in their house?

It's a very interesting thing because it's beautiful. It's a piece of like science fiction history. It's a part of the history of human ambition. Exactly. And storytelling. And storytelling. That is something that is also this piece of art, this really stunning piece of art.

So this is the real thing. Here's a picture of the real thing. This is IBM's quantum computer. This is a system two. This is, I mean, one of the most sophisticated objects in the entire world. The inside of these, the guts of them, they really are made of real gold,

partly because it's such an incredible, credible conductor. Also, these things need to be unbelievably cold. My favorite thing, by the way, about going to visit the proper one in Boston with IBM is that, I mean, you're standing there next to these machines that are worth quite literally hundreds of millions of dollars, right? The research project itself, probably billions. These are the most sophisticated machines in the entire world at the absolute cutting edge of technology. And then you go around the back of them and they're still using USB 2.0. They haven't upgraded to USBC yet.

Oh, I love that. So how you connect your computer to them is old school. Just USB. It doesn't work most of the time. Like even the most amazing places in the world, once you peer under the surface, it's all still gaffer tape and WD40. Well, I love that it's like this progression of more and more sophisticated

from the USB in the laptop all the way down to this like, cradled chip. What you notice is that the physical design of this, I mean, basically what you're looking at here, the guts of quantum computer, it's just a fancy fridge. I actually know basically nothing about quantum computing. I have to attack the things I'm interested in one at a time. And so I literally don't know what a quantum computer is. How much of it is real? How much is sci-fi? How is a cubit different from and better than a bit? I mean, just give me like the for a kid version. Oh, yeah.

Okay. So the thing is, is that they're sometimes presented as though they're better. And I think that that's the wrong way to think about them. They're definitely different. It's a completely different paradigm. And the way to think about it is that bits, normal computers, are ones and zeros, right? It's like a switch. It's on or it's off.

And what you can do with that is you can program things in a very deterministic way. There's no sort of extra probability that's thrown in there. there's no randomness. Everything ideally is like very controlled. You run the same program twice. You get exactly the same answer. That's sort of normal traditional computing. The quantum computer is based on a qubit, which you can think of instead of it being like a one and a zero,

like a yes or a no, it's much more like a distribution. It's much more like a, even like a dial, if you like. So instead of dealing with like absolute facts, yes is and no, you're handling everything in probabilities. My favorite analogy to describe this, although, you know, all of the analogies eventually break down if you think about them too hard. But I think that this is a good illustrative example. If you wanted to solve a maze using a traditional computer, the only way that you can do that is you start at the beginning and you try one route and it fails and you go back to the beginning and you try again and you fails and so on. With a quantum computer, because you're handling probabilities, you're handling sort of numbers that take on more than one value, what you can do is you can chuck a bucket of water in a, at the top of the maze.

And what that will do is flow through all of the various possibilities simultaneously and give you a sort of probability distribution at the end of what happened across all of those different routes. And this is like both the incredible potential of these quantum computers because it means that suddenly we are in a quantum world, right? We can handle probability and uncertainty and quantum effects actually. you can now model things down at the level of atoms in a way that's really, really hard to do

with a traditional computer that only deals in absolute certainty. Right. But it also simultaneously means that all of our encryption, essentially, which is based on this idea that you have to do things one after the other, after the other, after the other, that it will take too long for you to try all possible routes. It means that that is now out the window. It means that the way that we send secrets online,

that you keep your bank information to yourself or the way that, I don't know, even like national security ideas transported around the world without being completely open to anyone who's listening, a lot of that falls apart because as soon as a quantum computer can check every possible variation, our traditional encryption methods are no longer secure. Wow.

There are ways around it though. Maybe we'll talk about that in a different episode. Yeah, I would love to because I want to learn about this. It's unbelievable how little I know. So they aren't necessarily better at, you know, finding the square root of a three-digit number. A regular calculator can do that just fine. And Abacus can do that just fine.

But these can tackle problems that were literally so hard for other types of computers that that's how we make things safe. And their paradigm is so different that it's a whole new world. It's a whole new world, exactly. And there will always be things that traditional computers can do that quantum computers are rubbish at. The key difference is that vice versa, things that have always been hard to do on traditional computers,

like searching vast, vast, vast number of options. I mean, that in particular. Or trying to model what happens in the deeply complex intermolecular forces of the sort of quantum realm. All of that stuff, which has been so hard to get computers to do. I mean, AI sort of manages to do a little bit of that. But all of that now is suddenly open and available to us. So the real hope is that once you have quantum computers, things like drug discovery,

you know, understanding how molecules interact with each other and proteins, you know, to the point where you can actually design something at the level of atoms, suddenly become way more available. Or, you know, battery design, right? Like imagine how different the world would be if we could design better batteries. This is another one on the... list for quantum computers once we get this sort of up and running. And I do think it is coming, you know, there's a sort of a joke about how far away it is. Quantum computing has always been

30 years away, a bit like fusion. Right, right. But I think that we're really starting to see genuine progress. You've got not a quantum computer, but our like hopes and dreams as shown in a show hanging in your home. I absolutely do. You can, next time you're in London, Michael, you can come and have a glass of champagne underneath my Laplace's demon, my imagined version of a future with scientific advances. I should just tell you in the show itself, that quantum computer did not lead to good for humanity. So maybe be careful what you wish for. But nonetheless, yeah, I can cheer us to that.

Yeah. As soon as I turn it on, I'm going to get it to calculate how to pay its own electricity bill. That's what I'm going to do. There you go. If you have any questions that you would like us to answer or objects that you would like us to discuss, then you can send them in to The Rest Is Science at Gollhanger.com. Yeah, please do that. I cannot wait to hear from you. If you want to hear from us even more often, join our newsletter at the rest is.com slash science.

We're going to be back next Thursday with another edition of field notes and on Tuesday with our normal episode. Yep. See you then. Bye.