The Rest Is Science - The Scale of the Universe

Episode Date: September 2, 2026

The scale of the universe stretches from the Planck length, the smallest scale physics can describe, to the observable universe, the largest thing we can see. Travel inward from one and outward from the other by powers of ten and they meet at something astonishingly familiar: the size of a human egg cell. Michael Stevens (VSauce) takes Professor Hannah Fry on a journey through powers of ten, from quarks and protons and DNA to bananas and pyramids and on to planets and galaxies, to explore where we sit in the scale of the universe. Along the way they ask whether the Planck length could be the universe's smallest pixel, whether reality might be a computer simulation and just how empty space really is. Plus, your questions: why our best ideas arrive in the shower, Wikipedia's strangest rabbit holes and Hannah corrects the record on whether Saint Augustine and Thomas Aquinas believed curiosity was a sin. ------------------- You can find the Reddit thread for scale of the universe here: https://www.reddit.com/r/TheRestIsScience/comments/1uycf3l/i_visualized_michael_scale_comparison_from_the And The Power Of 10 documentary here: https://www.youtube.com/watch?v=0fKBhvDjuy0 See some of Hannah & Michael's favourite Wikipedia pages here: - Osama Bin Laden The Elephant - https://en.wikipedia.org/wiki/Osama_bin_Laden_(elephant) - Death From Laughter - https://en.wikipedia.org/wiki/Death_from_laughter - Order Of Magnitude - https://en.wikipedia.org/wiki/Order_of_magnitude - Amedeo Avogadro - https://en.wikipedia.org/wiki/Amedeo_Avogadro - Guy Standing (Economist) - https://en.wikipedia.org/wiki/Guy_Standing_(economist) -Guy Standing (Actor) - https://en.wikipedia.org/wiki/Guy_Standing_(actor) ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit ⁠https://www.cancerresearchuk.org/our-research/rest-is-science 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: Adam Thornton + Oli Oakley + Jack Meek Animator: Sam Benson Video & Social: Bex Tyrrell Assistant Producer: Lucy Lipscombe Producer: Simona Rata Senior Producer: Lauren Armstrong-Carter Chief Digital Officer: Samuel Oakley Exec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hello, welcome to the best of science. This is Hannah Fry. And this is Michael Stevens. Wow, that was a pretty good radio voice. That was, I think I sort of doubted myself halfway through. Anyway, this is field notes, which is basically a grown-up version of show and tell. That's right. And today I'm showing and telling something that I did not make. But you and I inspired, Hannah. Oh. Yeah, it's pretty cool. In fact, it almost makes me feel guilty. It's so cool. So if you remember many episodes ago, we were talking about weird coincidence. And we mentioned that human cells are like exactly halfway between the smallest size possible and the largest size possible. We are right in the smack middle. What does that mean? I don't know.

Well, on our subreddit, a user named Burrow or Burru, Burr-Roo. Burr-Roo. Yeah. What matters is that it's really cool. I'm going to send you in our chat, the Reddit thread, and we'll put this in the description and the episode notes for everyone to visit.

There's like, and read the comments because there's like multiple versions of it. This visualization shows an incredible journey that I'm going to take you through. And for those of you listening going visualization, a problem, don't worry, I'm going to walk you through it. What we're going to do is we're going to imagine a little game that you play with your friend, okay?

This is just giving a lot more color to this fact. So imagine that you start at the size of the plonk length, which is what? It's the smallest size physics as we understand it today can describe. Anything smaller than that, literally we don't know. Is it even possible? It's up for debate. It's almost a philosophical question. Can you observe something as small as the plonk length?

No. If you got light or any kind of, kind of information out of something that small or you tried to, it would turn into a black hole. Okay. And exactly why is a discussion we've had before. We can have again, but it's the smallest point. Now, imagine your friend is as large as the observable universe, okay? The largest thing we can observe, the entire observable universe.

And you both agree to start shrinking and growing until you meet in the middle. So every second, you get 10 times bigger. And every second, your friend gets 10. times smaller. This is what you're going to see. Okay, so you begin this little game and you start growing, your friend starts shrinking. For the first 10 seconds, you getting bigger are like super lonely. There's like nothing between a plonk length and then a neutrino. Okay. Oh, yeah. There's like nothing. Nothing's going on. Meanwhile, your friend who's getting 10 times smaller every second is passing the size of, you know, the great voids in the universe, super clusters like Lania Keo, where we are,

our local group, galaxies, Andromeda, the Milky Way. Eventually, after 10 seconds of this game, you are now as large as a neutrino, which is 2.8 yattometers across. And your friend is the size of the ring nebula, which is 1.3 light years across. This episode is brought to you by Cancer Research UK. Do you remember when we discussed why feet are so weird? Well, one particular footbone holds an even stranger surprise. It's helping shape our understanding of cancer timelines.

And for that, we're going to need to go all the way back before Neanderthals even existed to a 1.7 million-year-old foot bone. Researchers have identified a tumour in it in the oldest known example of cancer. in people. Which really shows that cancer is far from a modern disease. Beating a disease so deeply rooted in our biology won't happen overnight. But today, Cancer Research UK scientists are discovering incredible ways to turn our biology against cancer. In fact, Cancer Research UK has helped double UK cancer survival over the past 50 years. And their world-class research is driving even more discoveries to tackle over 200 types of cancer. For more information about Cancer Research UK, their research, breakthroughs and how you can support

them, visit canterresearchuk.org forward slash rested science. Do you wish you could just hit skip on the worst parts of your life? You know, the same way you can skip an ad? I get it. I'm Siaya and I live in Icecove. I've made some questionable decisions that didn't end up the way I planned. and today I'm still figuring it out. Somehow things usually get worse before they get better.

Apparently, that's how I roll. So bundle up and come along for the bumpy ride. Stream a new episode of North of North Tuesdays on CBC Gem. And now let's keep going. It feels like your friend is having a better time than you are. Yeah, your friend has had a lot more to see. They've had a lot more on their journey. Keep in mind.

I mean, this is a bit of a bit of, a spoiler, but I think that it's important to keep in mind where we're going. You are both going to meet in the exact middle, and in that middle is the human egg cell, the cell we all come from. Okay? So, the human egg cell is not only exactly in between the Plonk length and the observable universe, it's also exactly in between the size of a neutrino and the size of the ring nebula. Okay, because those are the same distancing from the air. on the scale. Yeah. That's right. They're like 10 powers of 10 smaller and bigger than the edges of our of our knowledge. Okay, after 17 seconds, you are now the size of a quark and your friend is now

the size of Earth's orbital diameter. What? Yes. What? Yes. You're a quark. You're not even up to a proton yet and it's that you come down to the Earth's orbital diameter. Isn't that incredible? It's very lopsided, isn't it? Wow. So your friend is like, it skipped out the whole universe and it's just down the just the ring that the earth? Yeah, two astronomical units. No.

93 million miles times two. That shows you just how small the plonk length is compared to like actual stuff and matter, right? Wow. And by the way, we are still way, way, way, way, way smaller than anything. that observable light would that light would give color to, by the way. We are below color.

We're going to reach color also in a lopsided way because after 20 seconds, you are now the size of a proton. And your friend is the size of the moon. Yeah. So your friend is now the right size for there to have color. Well, I mean, your friend has been able to have color for a long time,

but you still aren't. What? on earth. I am genuinely astonished. Okay, keep going, keep going. This is amazing. Yeah, isn't that weird? So again, keep this in mind.

The human egg cell is exactly in between the sizes of a proton and the moon. All right. After 24 seconds, you are now the size of an oxygen atom. And your friend is the size of the Great Pyramid of Giza. Wow. I didn't realize the small stuff was that small. I didn't realize. Is that incredible?

one second later, one second later, and remember every second you get 10 times bigger, your friend gets 10 times smaller. After 25 seconds, you are now the size of a carbon atom, and your friend is the size of the Statue of Liberty. One single carbon atom? Yeah. Okay, aside from anything else, I didn't know carbon atoms were 10 times bigger than an oxygen atom. Let's, let me give you the actual numbers here. So an oxygen atom is about 10 to the negative 10. meters across and a carbon atom diameter in meters.

Well, it's still 10 to the negative 10, but you're almost a power of 10 different. Okay, got you. I'm with you. I'm with you. After 26 seconds, you are now as wide across as a DNA molecule, and your friend is as wide across as a stegosaurus.

Right. from the entire universe down. Okay, yeah. All right. Two seconds later, 28 seconds into this game, you are the width of the COVID-19 virus. Right.

And your friend is the size of a banana. Still too small for color. Still too small for color. 30 seconds into the game, you are the size of a white blood cell. And your friend is the size of a grain of sand. What? Hold on.

What? Yeah. A white blood cell to a human cell? To a grain of sand. Wow. It's equal on both sides. A human egg cell. It is the biggest cell, right?

It's the biggest cell. It's biggest by a lot. In fact, you can almost see a human egg cell with your naked eye. Now, I think it's important to point out that, like, that difference makes the human egg cell different than if the answer, if the very middle of this scale was a typical human cell. Sure. Like a skin cell.

Maybe there's more or less poetry to it. Like, is it, is it the cells we're made of? Is it the cell that living things are made of? Not quite. It's the egg cell size. So what does that mean? I don't know. But we've reached the end of the game now.

After 31 seconds, 31 powers of 10 bigger, 31 powers of 10 smaller. You are both the same size you've met in the middle and you were both the size of a human egg cell. the cell we all come from. Phenomenal. Do you know, okay, I didn't play it because I wanted to hear it from you, but I'm just looking at it now.

This is honestly, this is one of the best things I've ever seen. This is absolutely phenomenal. It reminds me, do you remember the Powers of 10 video that was done in like the 1970s, this very amazing sort of science communication video? It was amazing. It took a human, a picnic, it zoomed out, powers of 10 every second,

and then did the same going smaller. But at no point in that was it making this direct comparison from one to the other. It anchors it in so much more of a real way when you are. Because I mean, I don't know how big the universe is, but I know how big it looks. I know how big it looks through a telescope even. I think this also shows how small the plonk length is. It's not like, oh, you get neutrinos and then, you know, beyond them. It's the smallest we can do.

No, it's way beyond them. Way beyond them. Okay. It's 10 powers of 10 beyond them. Yeah. And right, if you have some time, please, guys, go watch the powers of 10, like, documentary. It's a short, it's on YouTube for free. And I remember watching that as a kid.

And it just kind of put everything in its place. Right. And it was beautiful. And the people in the middle are having a picnic. in Chicago. And then I wound up going to university in Chicago. And I, like, thought about that a lot. I was so proud to be in the city where those people were in the Powers of Ten documentary. Like, it just, it meant a lot to me. Did you go, did you go find the exact park? Yeah, I did. I did. And I laid in the park. And I had to show everyone the video first because they had all seen it.

But I, I even have the, like, the scientific library book version of it where each page is zoomed out. I don't know if they went by powers of 10 or a thousand, 10 to the 3. But anyway, it's very cool. And Burrow, you have just added a cherry on top of a wonderful and important human endeavor. Honestly, that is the best version of it that I have ever heard of. That is so good. That has come alive for me in a really profound way. Burrow, that was, thank you.

Thank you so much. Can I just say one thing about Plunk Lenthe? Yeah. So I have spoken to some of the, I don't know how much they really believed it, but you know this idea about like the fact that we're living inside of a computer simulation. Mm-hmm. They sort of use plank length as plunk length as evidence of it, that like plunk length is like the pixel of the universe.

Yeah. Just so I throw that in. I don't know. I feel this like gut urge to not believe we're in a simulation. Me too. but I don't have any evidence for it. But I know. And in fact, like, when people talk about it or when I look into it to try to, like,

prove it wrong, I'm always like, ah, shoot. For example, if you can simulate a universe, it could probably be simulated a lot more simply than, like, a real one can be made. Like, if you can run an entire universe on some special advanced alien computer, then you could probably run a trillion of them simultaneously, in which case, statistically, we are much more likely to be in one of those simulations than in the actual universe where the simulations are running. It's just a numbers game.

So if you're open to the possibility that something with the resolution of our universe could be simulated as we experience it, then you kind of have to conclude that it's more likely than not that we're in one of those simulations. Yeah, I remember hearing, the first time I ever heard that argument

was Elon Musk giving a talk in about, I don't know, 2005 or something. No, maybe it was later than that, actually. But I remember hearing that. And I agree with you. I just, I just emotionally reject it. Yeah. Well, and it's easy to reject it and just say, well, you know what? I don't believe that the plonk length is the pixel. We just don't know enough about physics to go beyond it. Right. But here's my question. I don't know if you can answer it for me, but how do you explain irrational numbers in a simulation? Like pi is in the, in the simulation as a way to calculate the ratio between the circumference and diameter of a circle. But that number has, it can have infinite precision. Is there a point at which they said,

okay, look, we only need the first, you know, 12 Google digits and that'll be enough? Because if so, then we should reach a point where we're like, ooh. There it is. There it is. There's the end of pie, meaning we are in a simulation because it couldn't hold the exact, exact, exact, exact, exact, exact, never-ending precision of pie. Exactly. You're absolutely right. Because this is the thing, you know, the way that we've built computers, they are fundamentally discrete machines, right?

They're not continuous machines. You know, if you draw a circle on a computer and you zoom in far enough, you will see that there are these pixel-lates. edges, there are corners. There's no, there's no, there's no, there's no, there's not even diagonal lines, right? It's, it's sort of like a grid, a stepped grid. And so the whole kind of basis of this idea that we're inside of a simulation is that if you zoom in far enough, it's discrete and it just so turns out that with physics, it is discrete. People know the word discrete. I sometimes forget what words are, what words are real words and what words are just mass words. I say like with something continuous, every value in between is available. Okay, like, like a vinyl record is a, a,

an analog, it is a not digital, it is a not quantized, it's a continuous medium. Like the bumps in the groove can literally be, well, again, we get down to physics though, but they can have any size. You could make it as small as possible of a difference and that exists, but with digital music, it's got to be a one or a zero. Totally. That was such a beautiful explanation. And so, so the thing is, is that in our physical world, it feels as though things are continuous, you know? I can I can move my hand from here to there and there's no value. It's not jumping in between these values. But when you're doing something on a computer,

even if I was simulating that movement, actually zoom in far enough and it would be making discrete jumps. Any animation, any mathematical model is ultimately discrete. It has these jumps in it. You know what? Well, maybe we should save this and do a whole episode on the simulation hypothesis. Because I think it's really interesting. Yeah, I think we should because there's a lot more I want to learn

and there's a lot more to say about this. I also just realized that me trying to explain how collapsing the wave function is evidence of the simulation hypothesis is far too ambitious for this time on an evening as we're recording this. Yeah, so let's revisit it. But the point is that, guys, we just don't know. You might be real listeners or you might just be NPCs in the simulation that we are also NBC's running in. Is there someone playing? Is there like one person or one creature in this universe that's actually like, hey, hey, I am an avatar of like a real person in the real universe. And if so, who are they?

That's a question we'll leave for you. Leave your answers in the comments below. I've got a suggestion. We'll definitely do a simulation episode when we'll go really into it. All the evidence for, all the evidence against. One of them's going to be longer than the other. But nonetheless, I know which way in my conclusion. It could be two episodes. You're right. It could be we live in a simulation and then a week later we don't live in a simulation.

Okay. Should we go to people's questions? But let's have a break first. Yes, we're going to do that. So after the break, we will come and we'll read comments you've left in the past and respond to, answer them and enjoy them. So see you soon. This episode is brought to you by Cancer Research UK. When we talk about beating cancer, we often focus a lot on survival. And that can. mean overlooking impacts that last long after treatment ends. Yeah, for example, take cancers in children and young people. The treatments themselves can be incredibly harsh. They can cause lifelong side effects like infertility or hearing loss.

And Cancer Research UK is working to change that because young people, they should be able to grow up hearing the voices of the people that they love and living their lives to the fullest. That's right. And one clinical trial led by Cancer Research UK showed that giving another drug alongside chemotherapy nearly halved the number of children losing their hearing. And today, the treatment combination is being used by doctors across the world. For more information about Cancer Research UK, their research and breakthroughs and how you can support them, visit cancerresearchukuk.org slash rest is science. And we're back. First question, Michael, this one's for you.

another Reddit one here, Remote Island underscore 7798. You spoke about Osama bin Laden, the elephant, being one of your favorite Wikipedia articles. I feel I now need to know everyone on the list. Thank you for your attention to this matter.

I've got a couple of favourites as well, you know. I want to know your favorites. Throw them at me. Okay, I don't know, there's enough. One that I really love is dying while laughing, which is just the list of famous people who died while laughing. Oh, how nice for them.

And the circumstances in which their death was brought about during laughter. I really enjoyed that. That one's very good. Yeah, it's something to aspire to. So, I mean, there are so many good Wikipedia articles. And I feel like it's hard to compete with what you can get by just Googling best Wikipedia articles and reading every Reddit thread about them. There's even a Wikipedia page that just lists their most unusually.

articles. Like, just start there, you know? But, um, so, so I'm trying to think of things that I enjoy that maybe aren't already pretty well known. And I think I really like the orders of magnitude pages that Wikipedia has. I refer to those quite a lot. And there's, there's one for like almost every unit of measurement. You can, you can look up, uh, orders of magnitude length. And it goes, okay, here's every length in order and something that is about that size. So, um, there's also one for mass. And that's how I learned that I think every second, the sun converts an amount of mass equivalent to the Great Pyramid of Giza into pure energy every second. And that's, yeah. And that was just on the orders of magnitude page for mass. And it's like, here's this amount of mass. It happens

to be what the sun burns through in a second. It's also how much the pyramid of Giza weighs. And you look at this and you're like, this is amazing. I read those. There's one for, you know, time. There's one for sound, there's one for torque. There's even one for different orders of magnitude of torque. Like, here's this amount of torque. Ten times stronger would be this boat engine. Ten times stronger would be if you tied a string to the moon. It's just like, it's really neat. But what I want to also throw into the mix are just people who have the most hilarious or weird photos as the picture of them for their Wikipedia page. And there are some that just look really funny. It feels a bit mean-spirited, but like, go look at Avogadro's Wikipedia page.

Look at that guy's face. Okay. Look at his head. As in Avogato of constant fame. Of the constant. You worked out how many molecules there were in a mole, right? Yes, that guy. Oh, gosh. No human has ever looked like that. No human has ever looked like that. I kind of don't believe it. It's just a drawing. But it looks like a comic drawing. drawing? I don't know. It does. It does. It looks like spitting image, those puppets that you used to get on the BBC. But they do an extremely exaggerated version of, for example, Margaret Thatcher. So my question is, is that really what he looked like? Or did he look better? And this is unfortunate. Or did he look worse? And the illustrator was trying to be flattering to him. I've seen, there's another drawing of him that I have found. And he does not look anywhere near as strange. I think you're right that it's an exaggerated. version of what he looked. Oh, it is. That's disappointing. I was hoping that he really was like

the funniest looking dude in the world. And I just wanted to, I just looked up his birth date. He was actually, he was born in the 1700s, 1776, just about a month after America was born. But he did most of his work in the 1800s. The best one, though, I've saved my favorite thing. I actually, I actually laugh when I look at this and it improves my day. There are two humans named Guy Standing. First name guy, last name standing. So one is an economist at SOAS University of London. His name is Guy Standing. But his picture is of a guy sitting.

You've got, that's got to be intentional. The Wikipedia editors surely said the photo of guy standing must be a photo of him sitting. And it is. Oh, man, I love Wikipedia so much. I love Wikipedia so much. Isn't that wonderful? They are so deliciously nerdy, right? This whole community.

So amazingly, brilliantly nerdy. And this is, what a gift for humanity this thing was. It's a gift. But I said there were two people named Guy Standing. The second one is an actor. And if you look up the Guy Standing Actor page, there's a photo kind of, this isn't like his profile photo or whatever, but there's a picture of him sitting down with two other, with two women.

Yeah, it says, guy standing sitting. Guy standing sitting next to that's what it is. Guy standing sitting next. Yes. Amazing. Absolutely love it. I remember the other one that I really like actually,

which is inventors killed by their own inventions. That one is great. It's quite gruesome though, I'll be honest. See, that's a famous one. Yes, I love that one. There are so many articles where you're like, this topic is incredible. I'm going to read all of them.

And I mean, I'll spend multiple nights going through the like missing people Wikipedia article and just reading everything about them. Like if there's a name or an event or something and on the article it's it's a blue link, you know I'm clicking on that. It just keeps going deeper and deeper. Do you know about the philosophy thing? Yes, I do.

The game. I love this so much. So, and basically, sometimes I give a talk and include this. in there. But if you start on any Wikipedia page and you follow the first blue link on that page and carry on clicking through first blue link, first blue link, you know what I'm going to do it for you, Michael. Let's do it for you. Yeah, and walk us through what you're clicking. What is the first link? I mean, the reason what she's saying is that you always wind up back at the philosophy page because, of course, like the first word in someone's in any Wikipedia page

tends to be like more general. Like it is a planet, is a person. is an American or whatever. And you just keep becoming more and more general until it becomes so big that all you can really say is philosophy. Philosophy. It's like the why game. You know, Karen, asking why eventually you get to.

Philosophy. So yeah, do it with my page and walk us through. Okay. Michael David Stevens. You're an American educator. So I go to educator. Okay. And then it says a person who helps students.

A student is in a school. school is an educational institution an educational institution is about education which is the transmission of knowledge which is about facts into characterised as a true belief

a propositional knowledge is a version of belief then we've got attitude then we go to psychology which point we go to the mind question is quite long actually quite far away from philosophy Michael then you've got thinks you've got think or thinking is a cognitive process, which goes to mental processes. Goodness me, human brain, organ. Oh, whoa, we're leaving.

We're getting further away. Organism, living, matter, physical science, natural science, science, knowledge. We're going back. You're in a loop. You don't go to philosophy. I'm in a loop. We loop around knowledge. You don't go to philosophy. You're one of the rare ones. I don't go to philosophy. I'm an exception to the philosophy rule. You're an exception. Oh my gosh. But, But that would also mean that anything that gets to knowledge is going to get trapped in that loop. It is. Hang on. Guys, I'm going to have to check myself here. Start as they've changed my picture. I don't like that. Can I contact Jimmy a word about that. I also go to knowledge.

Uh-oh. Oh. So do you think we might need to update this fact? And someone may have already noticed this before us right now. Michael, it's broken. Is philosophy not the end point of the funnel? Is it basically a knowledge loop now? You know what? The thing is, is that, oh, no, it is. Knowledge is a loop. Someone needs to immediately update the knowledge, the knowledge Wikipedia page. They've broken it. I'm calling Jimmy Wales immediately. Right. Well, thanks. That's the sort of end of the talk I can give on that then, isn't it? Should move on to the next question? Yeah, let's move on to the next question. This one came from Margot on Reddit who asks, shower thought, is the reason that shower thoughts exist? at all due to the increased blood flow to your brain in the hot water. Okay, this is great. First things first, you're definitely not imagining it. People genuinely do have better thoughts in the shower. I know that I do.

I'm sure you do as well. There is a few reasons for this, but basically they come down to, you know the Chinese finger trap? well like the more that you the more that you kind of pull at something the harder it is to get yeah um your brain actually works a lot like that so you you have uh when you are working and you're really intensely concentrating on something whether it's like a a school problem or you know a work problem when you're really thinking really hard your brain is using all of its executive control networks um but when you switch over to a sort of autopilot task so something you know how to do you know how to

do, it doesn't really require your brain to think very hard or deeply, but you are doing something, like washing your hair, you know, yeah, going for a walk, going for a walk is ever so slightly different actually. But when you're doing something kind of repetitive that you don't need to think about, your brain stops its intense focus and instead it's the default mode network that takes over instead of your executive control networks. And the default mode network, this is like your brain's mind-wondering state. When you're sort of like allowed to kind of think about different things. You're,

your subconscious is able to freely associate the stuff. You can dig up old memories. You can, you can connect seemingly unrelated concepts. Well, your focus, the stuff that your focus brain would have filtered out because your focus brain is like, no, this is the thing in front of me. Right. But actually sometimes to solve a problem, what you need is the free association that comes from your default mode network.

So it's just much better. for that. There's also, actually, creativity is really heavily linked to dopamine, you know, sort of the neurotransmitter that feels pleasurable. And taking a really warm, nice, relaxing shower, it sort of, it feels nice, right? It feels good. So your body and brain is in like this better state already. You've got a bit more dopamine release, which then goes on to help your creative drive. But you're also, bluntly, you're not doing anything. You can't look at screens. You can't like distract yourself. It's one of the very, very few moments of an entire day when you are not locked to a screen in front of you. And so all of those things

together. When you go for a walk on the other hand, actually you are, you're increasing the oxygen to your brain. You're sort of, and glucose, actually, your, your, your, your, your, your, your, your, your, your, your, your, you're kind of feeding your brain, loads of nutrients, as well as all of these other elements as well. Interesting. But it's totally real. I definitely have found that. Like in the shower for some reason, maybe because I'm so focused on my body, I don't have as great thoughts in the shower. Who wouldn't be Michael if they look like you? Driving in the car or watching something kind of mindless actually kind of like brings forward better new ideas. And I need to, I don't know, I experienced this so often. I don't know why I don't do it.

it more often, that I'll, I'll be working on a problem with such focus all day and I won't get anywhere and I'll be so frustrated. But then what happens is two weeks, I'll give up. And two weeks later, I'll suddenly be like, oh, wait a second. Of course. It just kind of happened because I'm allowing my, my non-conscious activities to associate things and put something together. And I've definitely found that when I, when I need to write something, it's better for me to take a few days off and not think about it at all. And then, boom, it happens. Wow.

Yeah. Yeah. So the example I always think about with this is when I was doing my PhD, I at one point was stuck, so stuck on this unbelievably annoying problem. And I was stuck in it for honestly six months. And it just could not get this code to work. I'd written this bit of software and for a mathematical, model basically and I just could not get it to work. And I would like go into the to the kind of office

and I would sit there and I would try from the beginning of the day and work all the way through and nothing would happen. And then the next day and the next day and the next day and the next day and I would rewrite it and rewrite it and rewrite it. And then the day that I solved it, it's like the clearest moment ever after six months of this. I was like, I got up from my desk. I was so frustrated. It's been six months of this stuff and I walked to the toilet. And as I put my hand on the door to the toilet, literally as I'd like push the door open, I was like, oh my God, I completely know what the problem was.

And everything was immediately solved. Exactly. It's like it's unbelievable, unbelievable that you guys have been that many hours sitting at desk and it was when I wasn't at the desk that I managed to solve it. This segment is brought to you by Cancer Research UK. Our bodies, they're very clever. You've got all of these mechanisms that are in place to help protect us from parasites, from viruses, basically anything that's bad. But sometimes they can be a little over

protective and start freaking out over something that's not actually harmful. This is the type of situation when your tongue starts itching just because you've eaten a pineapple tart or a hay fever season that triggers a massive sneezing fit. Allergies are our bodies turning what was once an evolutionary advantage into a problem. But what if we could harness that defense system to do something useful. So today we are asking, can we turn our hay fever mechanisms on tumours? Starting from the beginning here, there are hundreds of species of parasitic worms and creatures that will quite happily crawl inside your bodies and make us sick. But these things, they're too big for our immune system to engulf it and destroy. So instead, our immune systems

evolve this special security system that will help keep these bigger things out. You get these antibodies called immunoglobulin E, or IGEE, and they have learned how to recognize a parasite, and then IGEE antibodies go in and will bind to specific patterns that appear on the surface of parasites, kind of a bit like how a key fits into a lock. And what that does is it causes your immune cells to just wake up, at which point they just release this massive onslaught of chemicals like histamines that cause things like coughing and sneezing, but will help to weaken and then expel the parasites from the body. So allergic reactions, I mean, there are this mechanism going wrong.

They happen when your body mistakes pollen or peanuts or whatever it might be for a parasite. In other words, essentially, allergies that are a misdirected immune response. So if your immune response can be misdirected, can it be redirected in ways that would be helpful? Well, that was the idea that came from a cancer research UK scientist, Professor Sophia Karagian. and she was studying allergies for her Ph.D. And her boss said, hey, I want you to be in charge of this experiment where we're going to look at allergic responses as a cancer treatment. Okay, imagine that. Imagine being like, oh, I'm allergic to cancer.

If I have it, my body gets into fight mode and attacks it. So their idea was to take those IGE antibodies, the ones that attach and cause allergic reactions. But what if we re-engineered them to bind to molecules? on cancer cells instead of onto pollen or food. Well, then those antibodies would start releasing inflammatory chemicals, and that local reaction would alert all the other immune cells and they would join in the fight. This idea has a lot of potential because these allergy-causing antibodies can launch a powerful and persistent attack against a threat.

If you turn them on cancer, our bodies could rapidly destroy the disease. So how close are we? This sounds amazing. This is like a big, bold idea. But of course, it's one that comes with risks. this proposed treatment that Sophia had come up with. Look, it's based on an allergic reaction and if you are provoking an allergic reaction in the body, you want to make sure that you're not having side effects like anaphylaxis. Anaphylaxis is a life-threatening allergic reaction

that can happen really quickly. It's when you get this sudden flood of chemicals in the body that narrows your airways and can stop you from breathing. Because of that risk, you know, the industry was a bit reluctant to invest. But then Sophia, she pitched her idea to cancer Search UK, digging into her biology, she managed to alleviate the safety fears to win their vital backing. And then after years of hard work, her team, they managed to launch this early stage clinical trial testing the first ever IgE antibody drug in people with advanced cancer. Look, this is designed at this stage to test safety at low doses. That's what an early stage clinical trial does. The treatment still managed to show promise, though. It shrank one woman's

tumor. So the idea now is that they're on the next stage of these trials. They're trying to bring this treatment one step closer to the clinic with the hope that in the future IG antibodies could be this widespread treatment approach that can actually save lives. I mean, it turns out that itchy eyes and a runny nose and odd rash, it's a sign that your body is working over time to shield us from harm. And our immune system is already doing the heavy lifting. We just need to teach it that the target is tumors, not tree pollen. Right, which sounds simple, but it all started as Sophia's radical idea. By backing these kind of ideas, though, Cancer Research UK, they deliver breakthroughs

that can help people affected by cancer. In fact, eight in ten people who receive a cancer drug in the UK receive one developed by or with Cancer Research UK. And this impact is felt globally too. Over half of the world's essential cancer drugs have been developed by Cancer Research UK or with them. And for more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit Cancer Researchuk.org forward slash rest is science.

All right, let's do the next question. This is one from Ben who came in on email. Ben asked a simple question, how dirty is space? How dirty is space? It depends on what you mean by dirty, right? Like just full of debris is how I'm taking it. And the universe is famously, like, basically empty. There's nothing here.

I think despite the fact that, you know, in our daily lives, we're surrounded by stuff, by matter, by atoms. We've got statues and books and food and people and trees and ground and buildings. In between all of that and the next big clump of stuff, like Venus or Mars, there's like basically nothing. Not totally nothing. but if you took all the matter in the observable universe and compared it to how much space there is, it evens out to about maybe an atom or two per like three cubic meters. What?

Yeah, it's like, and so imagine a clothes dryer, like three of those volumes, on average you'll be able to find in our universe like one atom in that space. And that's it. Hold on. Are we talking about American clothes dryers or British ones? because American ones for sure. The British clothes dryer is just like a weird foldy ladder thing

that you put clothes on and it makes your room all humid and it makes the clothes smell. It's great. No, I do think that they can work really well. Like here in Colorado, they work great. But in New Zealand, in the winter, like the wettest time of the, it's, they don't dry. No.

It's more of like an algae farm is what those things are. This is what I hear of Americans who moved to the UK and they're like, what are you doing with your clothes? Anyway, you don't just put them in a big hot box that blasts them until they're bone dry? Yeah. Climate change, what climate change? Okay, so that's, I would say not dirty. If you had like three massive washer dryers and one at a minute, now that we know how small, an atom is, especially, given the first half of this episode. Yeah, I know. I know. We think Adam and we think like, oh, okay, so three cubic meters and

there's like a little dot in it. No, it's not a little dot. It is an invisible dot. Okay. Yeah. It doesn't have a color. Light cannot interact with it in a way that we can see with our eyes. It's not a mode of dust. It is a septillionth of that. Yeah. I do like the idea that that you could create a chamber, say a sort of glass chamber of this amount of space, have one atom in there and someone going to be like, it's so dirty. It's so, it's so dirty. Yeah.

This space is a big style. But there isn't much stuff. I mean, in a way, it does feel like a lot because if you think of outer space as being like a vacuum, then, you know, that's averaging out not too badly. But there is a little bit of material in between planets. in between stars, in between galaxies. But again, we're talking about like even less than the analogy we just gave. Like maybe a tenth of an atom per cubic meter.

I mean, it's very small. There are different calculations. Different numbers have been arrived at here. But the universe is spick and span and it's nice and clean. But that also should make us feel very special to be part of the matter. It's very rare to be matter. if you happen to be any, any volume in the universe, to be one filled with matter is quite, quite rare.

And even rare it's a biological matter where you are, you are basically locally resisting the pull of entropy towards disorder. It makes me feel very special. We are very special, Michael. We are extremely special. I mean, why me, though? You know, it makes me feel guilty. I'm like, why do I get to enjoy all of this?

Oh, brother. Why these atoms? Why not? Why not, why me? Why not other atoms instead? And then I look at a cheeseburger and I'm like, you're going to be, it's your turn next guys. And then they get to be a part of me for a while and experience consciousness and life.

But they always got to be madder. But one of these days they'll become energy, right? Like my body is warm. I'm a mammal. That's waste heat that's leaving. And that's just energy. So eventually they will get turned into not matter. Eventually we all will.

eventually we all will. Okay, that kind of brings us to the end of our episode. But you know what? There's one thing I wanted to say actually before. Oh, good. Before we go. Because, right, this is the rest of science. And I take a scientific approach, which also means that inevitably,

sometimes we are going to make mistakes. That's just, that's like a, that's just a fact of life. And so I am extremely grateful when listeners and viewers point out the mistakes that we have made. And I made a mistake on our curiosity episode, Michael, and I would like to correct it, yes, because Kevin Carnahan, Professor Kevin Carnahan, no less, who is a professor of philosophy and religion at the Central Methodist University, he made a little video, he clipped up some of the curiosity episodes that we had. And where we were talking about Augustine and Aquinas, and I was saying that they were a bit anti-curiosity, right? that they were sort of, they were, they thought curiosity as a whole was kind of considered a sin. And I was a bit snobby about it and I was saying, well, it's kind of quite useful if curiosity is a sin if you're sort of trying to persuade an entire population of people to, to not question

something, to do as you say. Yeah. Anyway, it turns out, I got it wrong. I misread the history and I was a bit too broad in my dismissal of Augustine and Aquinas. They, actually weren't against asking questions or curiosity full stop, what they condemned was a particular type of curiosity. They were condemning, prying, morbid gawking, or sort of seeking knowledge just to show off like a vanity thing. So when they called curiosity as in, they really meant a lesser kind of curiosity is that there were different types of curiosity. So my bad, I take it back. It's good to know. And it's good for all of us to know. They weren't against curiosity. They were just buzz kills.

But yeah, no, I love that. I love that. And so please let us know meticulously. I want every detail. Let us know everything we get wrong or could have said better down in the comments below. Absolutely. For real, for real. Not just saying that.

You know, Michael and I, we've got a team of researchers who help us with these episodes, this amazing team of producers behind us. But it's inevitable, right? That we're not going to get everything absolutely right. And we are extremely grateful when people point out our mistakes. I really, really honestly mean that that's what science is, right? That's what science is, it's the march towards progress collectively. And that's always been my attitude to it.

So thank you for pointing that out. We really appreciate it. Yeah. Yeah. So keep it coming. Yeah. Keep the questions coming. Keep the questioning coming.

We are not always right. We are just along for the ride. I don't even consider myself a Sherpa. I consider myself a fellow traveler in this journey of thought. A fellow morbid gawker. And keep morbidly gawking. Okay, I don't care what Augustine said. Like, if you want to know about, I'm trying to think of something.

Do you want to know about inventors who have been killed by their own inventions? You go look at that Wikipedia page, my friend. Please, do. There's a reason that page exists. And there's a reason it has the page numbers, the page views that it has, okay? Absolutely. Okay, we will be back next week. But in the meantime, please do.

send us your questions. The rest of science at goahunger.com and leave comments on the video, leave comments on Reddit. Among us, we read all of them. So yeah, we will see you next week. Later.