The Rest Is Science - The Lake At The North Pole That Stops Europe From Freezing

Episode Date: August 12, 2026

When you picture the North Pole, you probably imagine a vast, frozen expanse of floating sea ice. But hidden deep beneath the surface of the Arctic lies something incredible: a massive, churning reservoir of nearly freshwater, suspended right in the middle of a saltwater ocean. In this episode of The Rest Is Science, Professor Hannah Fry and Michael Stevens (VSauce) explore the hidden hydrodynamics of the Arctic. Fresh off a real-world scientific expedition to the sprawling ice sheets of Greenland, Hannah shares firsthand accounts of the colossal forces currently reshaping our polar regions. Together, they unpack the bizarre physics that allow a gigantic freshwater lake to form beneath the Arctic ice. Fancy some some of your own glacial water? https://svalbardi.com Send questions of your own to [e-mail] or find us at r/TheRestIsScience. ------------------- 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: 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 and welcome to the rest is science. I am Michael Stevens. And I'm Hannah Fry. And today on this episode of Field Notes, I have no idea what's going to happen because it's Hannah's turn to report back from her expeditions in life. What have you got?

Do you know what? Expeditions is exactly the right word for today's episode. Because I've just got back from the Arctic and I sort of don't want to you. I've changed my camera position around here because all of my sort of my thermal wear is laid out across some brawl behind me. I sort of want to kind of hide it.

Also, you're trying to hide your floor. And just, I'm hiding my floor. It may peak into view at certain points during the course of this episode. But I brought you back, I brought you back something pretty exciting from the Arctic, Michael, which is today's subject of conversation, which is a little bottle of water from the North Pole. Oh, wow. Isn't that cool? Okay, so what's the North Pole like right now?

Was there liquid water there or was it an ice sheet? No, I didn't actually get to go to the North Pole. How high did you go? I went, let me see, I went seven. Hold on, I need to stop using this northern hemisphere-centric language. How far north did you go? Yes, not how far up? Let's not be biased here.

Okay, so I was on an icebreaker that was setting on. for an expedition to the North Pole. And I met up with them in Svalbard. And they left as I was there. I sort of waved them off from the dog. So this was their previous expedition. It's the Norwegian Polar Institute. Because the thing is, right, when you, I was going to film this program that I'm doing, right?

And they've got their own stories, yeah. But when you go to like these unbelievable places, you find out so much more stuff than you can possibly ever fit into a TV program, right? And so what I thought I would tell you about today is this, this like, wild thing that I discovered that I had absolutely no idea about while I was off in the optic. Because if I, if you drank this little bottle of water that had been collected from underneath the eye sheet at the North Pole, what do you think it would taste like? That's my question for you. Good question. So my first thought is salty. Wrong. Really? Totally wrong. Is it fresh water? because of what? Because it's melted ice?

Okay, yes and yes, and there's so much more to it than this, and I had no idea about this at all until I sort of went up there to go and see. 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's 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 football.

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, visitcancerchurresearch.org.

When Westcham first took flight in 1996, the vibes were a bit different. People thought denim on denim was peak fashion. Inline skates were everywhere, and two out of three women rocked, the Rachel. While those things stayed in the 90s, one thing that hasn't is that fuzzy feeling you get when WestJet welcomes you on board. Here's to WestJetting since 96. Travel back in time with us and actually travel with us at westjet.com slash 30 years. Hello, mid-sized business. We see your big ambitions, but how do you achieve the wins you want when your technology is holding you back?

SAP Grow is built to grow with your business, no matter its size. With AI embedded at its core, working across every system, all ready to go from day one so you can hit the ground running. Bring it with SAP Grow. AI Cloud ERP for any size business. So, okay, fine. When rain comes down, you know it's freshwater. When it freezes as snow, you know that's fresh water too. Fine.

But here's the thing, when seawater gets really cold, cold enough to freeze when it's about minus 1.8 degrees C, The water molecules, they start locking into this rigid crystal lattice. But this geometric structure doesn't have any space for the salt ions. So it just kicks them out. It kind of just kicks them up further and further and further. And then what you end up with is like the ice that is floating on top of the sea is like fresh. You can take a chunk of older ice and drink it. And there is one company that I came across that is.

that is now actually selling this as though it was sort of wine. It's unbelievably expensive the prices that they're selling this for. Svalbardi, the water. Polar Iceberg Water. What they're saying here is this is pristine ice. It's been locked up for millennia sometimes. Fresh as the day, it fell as snow. So they gather it, they melt it, and then they sell it for,

hang on, let's just get up the live prices right now, for a single bottle, right? 750 milliliter bottle of water, Michael, 100 euros. I've got a few questions. They are melting icebergs to make this water? Yes. Okay, so the water maybe has been in that iceberg for a long time. Because my first thought is, well, look, I'm going to flush the toilet after this podcast.

Eventually, some of those molecules will be at the North Pole. Like, it's a whole water cycle, guys. It's not special water up there. Every molecule gets its turn. Every drop gets its turn up there. But if it's trapped in ice, then it can spend a lot longer somewhere or not somewhere. So this is water that they say on the website that they're collecting it just before it melts away forever. Right.

It's pristine ice locked up for millennia and fresh as the day it fell as snow. Now, I wouldn't say it's fresh. I think the process of turning into glacial ice takes long enough that there's going to be some dust. There's going to be some bacteria cell walls in there. But anyway. A little mammoth hair every now and then. Oh, a mammoth hair would be really cool. So you don't have one of these, but you do have an even more rare kind of water, which was collected by the Norwegian.

What? It's the Norwegian Polar Institute. But this is actually from the North Pole, like for real, for real, for real, the North Pole. Not just 78 degrees north, but 90. Exactly. Anyway, so here's the thing about this fresh water, okay. So for thousands of years, the Inuit people have known, the indigenous people of the Arctic. They've known that you can eat sea ice and it's fine, right?

It will hydrate you properly. But it all depends on what it looks like, right? So if it's first-year ice, if the ice is really flat and it's a little bit grey and it's got these sharp and jagged edges, then don't. But if the ice is thick, it's sort of multi-year ice. If it's more rounded at the edges, also if it glows slightly blue, then you're fine. Because by that point, the salt within it will have been squeezed out by this process of sort of melting and then refreezing, or slightly melting around the edges and then refreezing in summer and winter. What was really funny about this, though, because when Europeans started like pushing up in the north,

in the Arctic in the 16th century, especially when they were looking for the Northwest Passage, the way to connect Europe to the Americas. What they were doing, they had no idea. They knew you could eat snow, fine, because that's fallen as precipitation. But they did not know that sea ice would be fresh water as well. And so there were all these stories of people, you know, from 1500s or whatever it might be, where people were running dangerously low on water and they're literally about to die of thirst, you know, they're all about to just literally wither away.

And then there's one particular story of Martin Frobyshire, 1578 this is, and they were in desperation. They hauled a chunk of sea ice on board the ship, melted it. And then to their absolute amazement, it was fresh. I mean, they just couldn't believe it. Because it sort of logically doesn't make sense. If you take a load of salt water,

why on earth when you freeze it, would it end up removing the salt from it? I got a question. The vial of water that you, you have. Mm-hmm. Was that originally collected as ice and then it was melted, or was it collected as liquid water? You are too smart.

Okay, so this was actually collected from the bottom of the ocean in the North Pole. So it says on it, it says that it was collected, here we go, 4,302 meters underneath the ice sheet. Wow. So this is your, you know, you're extremely smart here. because actually I think if you tasted this, it would end up being salty. But it turns out that this stratification, as it's known, essentially what happens, this unfrozen water absorbs all of the rejected salt. It becomes really, really salty, freezing cold liquid.

Okay, so I thought this was liquid water collected. So I assumed it would be salty. But you're saying, I feel like frozen water, ice would not be salty. because the salt would lower the freezing point of the water. So it just wouldn't freeze. If you go past minus 2 degrees centigrade, it will freeze. Okay. How many vials do you have?

Just that one? Just have the one. Hannah, you got to get two so you can drink one and keep the other. What you really want is one from the top and one from the bottom and then a little sip from each. You want one from every like 10 feet of depth so that you can have a little, you'd pair one with a steak and one with your ice cream. as you go along, as you go along. Can I tell you a little bit more about this fresh water, like massive lake, and it's massive, by the way, that is hiding underneath the sheet ice and the North Pole

because it turns out it's like responsible for almost all of the dynamics of our entire planet. Like it's wild, and I had no idea that this thing existed. I didn't either, but you call it a freshwater lake, but really it's a giant parcel of water surrounded by water. Right, it's a lake sitting on top of a notion. right. But the thing is, is that I'm not talking about

a small amount of fresh water here, right? I am talking about gargantuan amounts, more than all of the Great Lakes. Because in the summer, when all of the snow, all of the glaciers melt from Siberia, from Greenland, from Canada, from Spalbard,

all of them empty into this great big basin that appears at the North Pole. So if you looked at the ground, the sort of the terrain under the ocean, beneath the North Pole. It is this little bowl. It's like this, it's a perfectly shaped little bowl.

And with the Coriolis effect of the earth spinning, it's sort of this spinning little blob. I mean, it's not little. This spinning gigantic blob of fresh water that is sitting on top of a very salty part underneath. The other thing about this, okay, so this freshwater blob that is sitting there under the ice sheet,

The really amazing thing about it is that it is protecting the ice from melting because that warm water that is coming up from the Atlantic, there is easily enough energy in the warm waters of the Atlantic to melt the entire ice sheets of the North Pole, right? Gone like this. The only reason why it doesn't and hasn't is because this cold water blob is stopping it from getting there. Because the salt water, even though it's water,

warm, sinks to the bottom beneath the much lighter cold fresh water. So it can't get to the ice sheet. It's like it's insulated, perfect insulation. Right. So you're like, oh, great, thank you very much. Thank you very much. Blob of cold water. I really appreciate this for not getting rid of the ice sheet.

The Arctic can survive all of the creatures that need that freshwater lake to just to live and all of the creatures on top that sort of feed from it are extremely great for as a result. However, here's the big problem. The big problem is that the ice sheet is still melting from the top. You know, the sun is still beating down on it. Yeah. It's still more heat in the atmosphere than there was before,

which means that this blob of water is getting bigger and bigger as time goes on. And the real fear is that there'll be a tipping point where the blob gets so big that it shuts off the flow coming up from the Atlantic, where you've got this giant like evacuating lake of fresh water that spreads out into the Atlantic stops the warm water from coming up, at which point it's by-bye mild winters for Europe. Right. It becomes very cold as it should be based on latitude alone. Based on latitude alone. Oh my gosh.

And you know, like, okay, well, maybe this isn't that big of a deal, you know? Like they can live with it in Moscow, they can live with it. In Canada, no big deal. Except that every single bit of infrastructure in Britain is built, as we have learned this summer, right, is built for a very narrow range of temperatures. Really, Brits are happy between plus five and plus 25. That's it. That's all we're happy with. You know, if it gets over 25, we break down. If it gets under five degrees, it's game over for us. Yeah, things will need to dramatically change infrastructure-wise. And up until now, this big question of this blob of water that protects the ice sheet, but threatens the temperature of Europe, what is it going to do? Is it going to stay there? Is it going to stabilize? Is it going to grow? Is it going to shrink? Which way is it going to go? And for a really long time, people were like, no, no, no, no. There was a group of people who were like, no, no, no, this is protecting the ice sheet. Actually, we're in a state of stability. This is not a problem. But in the last couple of years, things have started.

started turning for the worse. And now the models are saying that it is genuinely possible that by 2070 or so, this conveyor belt of warm water from the Atlantic, moving up towards the North Pole, will start slowing down enough that it's really going to be bad, bad. In our lifetimes, basically, Michael. Has anyone named this freshwater lake blob? Yes, the lake vlog.

Yes, they have. It is called Beaufort Gaier. Oh, wow. Beaufort Gaier is a fantastic name. I didn't even know it was there. I had no idea it was there. No, I just assumed it was regular ocean water everywhere. But apparently there's this structure of like floating sea ice.

Then you've got this Beaufort Gaier of fresh water. And then below that, you've got the salty, even probably maybe more salty than regular ocean water. Should I open it in to have a little sea? Well, yeah, of course. I wasn't going to ask you to because it would be awkward, but you should. This feels like that moment when you lick the rock, you know? I know. There are risks here. I am, you're doing this under your own free will. It's salty. Oh my God, that is the saltiest thing I've ever tasted. Okay, so it's, it's from what, 4,000 feet or meters? How deep? Meeters. Wow. Okay. So you did it for the gram. You took the sip and it was really salty. So saltier than regular.

sea water? I think that's salty than regular sea water. Yeah, well, it makes sense. I don't make it a habit of drinking seawater from little vials, but, but in my experience, that is extremely salty. Wow, and aren't you glad that you've tried it now? Yes, I am. Maybe I'll, maybe I'll sprinkle a little bit on my dinner later and say, well, do you know what I think is so amazing to imagine, though, is that like this little bit of water that was literally at the bottom of the North Pole, you know, nearly four and a half kilometres at the bottom of the North Pole. Think of everything that swam above it, you know? Like, think of everything that there has been seen in that area, but we just have, it's so uncharted. We just, we just have so, so much to learn about, about our oceans. And, you know,

the Arctic in particular, it's like, it's wild to me. It's wild to me, just what that could have seen. You know, I bet if I did some DNA analysis of all of the different creatures who's, you know, floating little fragments of DNA have wafted through this, I bet there would be so much to learn from this little vial. There'd be so much DNA we didn't even recognize. Species we have not seen yet. And now, and now I've assimilated it into my own body. You've consumed them. Yeah, you're one with the Arctic. Next step is to to brine some chicken with that, I bet it would be too salty. Too salty.

Listen, let's call it my Nalwilf smoothie, okay? Yeah, that's what it is. Okay, that was my little addition for this week. Hope you enjoyed. They're not always going to be that good. I think that was a particularly good job. That's really cool. Yeah, it's not always going to be the case that you've just come back from the Arctic,

but you have these adventures and you just show up on the podcast and go, oh, look, I just got back from the moon. sorry, my floor's a mess. And I'm like, ah, yeah, I know what that's like. You go to the moon of your mind, though, Michael. Also, I haven't been to the moon. Oh, that's right. The moon in my mind.

And you know what? We're going to visit these cognitive lunar landscapes after the break when we answer some questions from you all. When Westcham first took flight in 1996, the vibes were a bit different. People thought denim on denim was peak fashion. Inline skates were everywhere. And two out of three women rocked,

The Rachel. While those things stayed in the 90s, one thing that hasn't is that fuzzy feeling you get when WestJet welcomes you on board. Here's to WestJetting since 96. Travel back in time with us and actually travel with us at westjet.com slash 30 years. Right now, for a limited time, everyone's part of the Buick team, even you. Buick's employee pricing for you event is on now. Get a purchase credit of up to $3,168 on a 2026 Buick Envision. Surround yourself with signature Buick. refinement from an available massaging driver's seat to an expansive panoramic moonroof and a stunning

ultra-wide 30-inch diagonal screen. Don't miss Buick's employee pricing for you event. Visit Buick. Visit you for more details. All right, we're back. We have got your questions. The first one is from Reddit. We've been hanging out on the subreddit. We haven't posted it. I haven't posted it. Have you posted it, Michael? Well, no, I can't post. As I said before, I can't use my Reddit account. I can look at things, I cannot upvote. I can't comment because I have to change my password, but I can only do that if I have access to my old at google.com email address. So I'm stuck.

I'll need to just make a whole brand new account, but it's sad because I like my username, just Michael underscore Stevens. It's a good one. It's the one I've been using. Anyway, I have been lurking on our subreddit, not able to engage, and I loved this one.

It starts, this is what it's called. It was written by Fossi. Fossi says, I think this podcast spreads misinformation about science and the moon is flat. Just kidding. My real question is why are people more likely to correct someone online with a detailed explanation when they post something wrong, but are much less likely to give the same kind of thoughtful answer when someone genuinely asks a question? I loved that because first of all, it proves how significant this phenomenon is.

I immediately click on this one because I'm like, uh-oh, someone's being. mean and wrong on the internet. Time for me to engage. And I come in and then I see that that's exactly what their question is about. This is a famous part of the internet. Like the fastest way to get help online is to be wrong.

If you want to know what kind of wrench to use on your 22 Kia, don't ask, say, hey, here I am. I'm about to use a hammer to undo this fastener. And then everyone's going to go, don't do that.

And they'll tell you what to do. Why is that? And as it turns out, out one, it hasn't been studied online nearly as much as I expected it to have been studied, but it falls within the purview of the psychological study of the difference between helping and fixing. Those are two very different behaviors that sometimes look the same when you're far away, but are very different things. And I think the first place to start is to recognize that when someone posts online, or even in real life, asks a question,

that's a very open-ended challenge. You know, what's the best way to cook ribs? Well, there's a lot of different opinions. There's a lot to cover. There's the tools. There's the time. There's the temperature. There's what kind of ribs?

What kind of cut? Is it spare ribs, St. Louis style? It's a lot. It's a lot of cognitive effort. But if someone shows that they're going to be microwaving ribs, boom, you've got one thing to pick on, which is don't do it that way. Or, I don't know, maybe you can microwave ribs. No, but the point is, just on the surface, they are very different things. If someone's wrong,

they're specifically wrong. But if they're just curious, they are open-endedly curious. I mean, that brings us back to that episode that we did about curiosity, right? Which is where people are most engaged when it feels like a missing tooth, where you know exactly the size and shape of the piece of information that needs to fit in it. And that's when you sort of get people's attention the most. That's right. So someone wrong on the internet is like a weird gap in your teeth that you just can't stop sticking your tongue through. You need to be like, I know what goes there. I know what goes there. You know what goes there. You know what to say. And the whole phenomenon, or rather, the whole feeling behind someone being wrong on the internet feels more urgent. Because again, it's a specific thing and it can spread. Whereas someone not knowing something is not as urgent. Okay. Someone, will fill them in, someone with more time than me, you can sort of do what's called social loafing

where, because so many people are looking at this question, you'll let someone else answer it. But if someone's wrong, then that is a thing that has legs. It's more real and it can spread and others can get that information and they can do something wrong, break their microwave, ruin their dinner, hurt themselves. So you've got to act. But then at an even more general level, fixing is easier because it's much more egotistical. It is about easing your own discomfort. Someone was wrong online, and that makes you annoyed.

And so to make yourself feel better, you come in and correct them. It's also like a judgment thing. You're judging the person's action and their theory. And that's fast for us to do. We evolved to make judgments very quickly. Good, bad, retreat, approach. Those are fast things. But helping requires listening.

It requires reasoning. It requires figuring out what the person already knows and what kind of knowledge base they have. And it requires sharing someone else's perspective. It isn't just about reducing how your discomfort. It's about sharing someone else's discomfort and working through it with them. So it's a lot harder in like three ways. Correcting someone, piece of cake. We do it instinctively.

But helping someone in an open-ended way, that's a commitment. So you know, there is this trick. I possibly shouldn't admit to this here because then maybe I'll weaken the value of the trick in future. But sometimes when I make my TV documentaries, I get to interview scientists a lot of the time. And sometimes scientists who are so amazing in their own field really struggle to understand what the best possible way to describe it to somebody outside of their field essentially.

I think it's just really difficult to find the word that capture the joy or the gloriousness of the thing that they're studying. And so sometimes you sort of have to help the scientist along, right, in describing their own stuff for what you know the audience needs. So anyway, if I'm with the scientist and they're being too technical, they're sort of, they're kind of in their own head a little bit, they're just being a bit too nervous, whatever I'd be. The trick that I do, and it works, I would say, 98% of the time, is I will come up with an explanation and present it to them something incredibly simple, something that I know the audience would like, but deliberately get one little detail wrong. And then what will happen is that the scientists will be like, no, no, no, no. It's like this. And then they'll repeat my exact same explanation, but change the thing to be right. and then often add a little extra detail on on the end,

and like nine times out of ten, that is the clip that will actually use when it comes to the edit. But I don't necessarily know that that's why I'm doing. But honestly, it works so well. I bet it does. It's brilliant because you're giving them something much easier to hold, which is a specific, incorrect thing, rather than an open-ended, like, so what are you researching?

Oh, brother. They're going to immediately talk as though they were talking to a colleague. But if you say, oh, okay, so like rocks have been here since the Big Bang, they go, no, no, no, no, no, no, here's how rocks form. And you've given them a thing to push against. Exactly right. Yeah. You're reminding me also of that XKCD comic. So in the comic, these two scientists are talking to one another, and the first one says,

silicate chemistry is second nature to us geochemists. So it's easy to forget that the average person probably only knows the formulas for Olavine and one or two Feldspars. And then the other scientist goes, oh, well, and of courts, of course. And they go, oh, yes, of course. So that's how it is talking to experts often. They think that you have, at worst, like, a graduate level, like entry to graduate program knowledge. And really, you're still thinking, is quartz a rock or a mineral? Or, like, what is it?

Is that the thing that they put in watches? What are we talking about here? Right. Totally agree. I also think that sometimes scientists, I do feel a bit bad for them. I think that they are playing in their head to the audience of their peers. Everybody is nervous about how they come across. Every single human on earth.

And if they're not, then I don't trust them. And so I think sometimes people are like, they want to say the thing that makes them sound smart because their audience will hear it. But actually, it's the audience at home who are more important to listen to. Well, yeah, and there's a really big difference between explaining to a general audience a field versus talking about the specific thing in the field you've spent 10 years working on, which is like just the way a certain granule size of quartz moves through a riverbed in the northern hemisphere. And so that's where your mind is.

And it's hard for you to go back and say, okay, so water flows downhill. Like, let's start here. And I think that, yeah, what you just described is a brilliant way to get them, to give them handles to hold on to back here so that they can, you know, take us the rest of the way. Isn't there something about how on naval inspections they would always deliberately leave a rope? I'm sort of half remembering something. You would always deliberately leave a little bit of rope that was like unfurled and not right. And then just to, because I think when people do inspections, they always want to pick up on something so that you deliberately. leave something really obvious that they pick up on that and then they don't they don't sort of, they feel like they've done their job properly.

Oh, yeah. Well, I think you can be quite snaky about using this against people. Yeah. No, this is, I feel like I've heard jokes like this before where, oh, yeah, if you want to lie about something, your cover-up should be, should include something embarrassing or also kind of illegal, but not as bad. Because then people think, well, why would you, you know, how would that not be true? You know, it took a lot for you to admit that. And it harmed you to admit that. So it's more believable than if you just said, oh, I'm innocent here.

Wish you told me that before I went into traitors, Michael. Okay. Shall we? That's going to only make sense for the British audience. But there we go. Okay, should we go into the next question? This segment is brought to you by Cancer Research, UK. Now, in the laboratory, a lot of things can kill cancer. But as it turns out, killing cancer in the body is a much bigger challenge.

Yeah, of course. And that is because cancer cells are our own cells that are gone wrong. You know, they're literally part of us, which is going to make killing them much more complicated. Exactly. And also, our bodies are these incredibly complex mazes. They're labyrinths. And so for a drug to launch its attack, it has to navigate all of these. twists and turns to reach just the right spot. So today, we are asking, could a bath time essential

steer us in the right direction? Obviously, that's where we were going with this. Obviously, the lead-up was there. Okay, the science behind this is absolutely amazing, though, because if you think about chemotherapy, chemotherapy is extremely effective at killing cancer cells. But the reason why you get sometimes such serious side effects is because it can also kill your own cells, right? It's really difficult to distinguish between what's you and what's the cancer. So what you would like to do, ideally, is to target the chemotherapy right at the point where the tumour exists and bypass all the rest of your tissue. The question is, how do you do that? How do you navigate the complex maze of your body to get it there? So, Cancer Research UK scientists, they have developed these tiny little

drug laden bubbles that can float through your body and then burst in. I can hear you thinking why bubbles? And the reason, the reason is because they are part gas, part liquid, but at the same time, they're solid enough that you can manipulate them. So you can, you can sort of create them, move them around, wobble them as you like. The other thing about bubbles is that you can pack the inside of them with the drug that you need. You seal the chemotherapy inside those micro-bubbles. And we're talking really tiny here, right? One to 10 micrometers in diameter, smaller than the width of the human hair, over 30 times smaller than a grain of table salt. Really, really, really, minuscule doses of extremely potent drugs. But to get them

to the right part of the body, you need some sort of guidance system. So you inject them in, and then these micro-bubbles will find their way to the cancer, either because they are attached with loads of antibodies to them. So it sort of uses the same technique as your immune system does to hunt down an infection, but instead it's these bubbles that are hunting down a tumor, you know, at which point it has the chemotherapy inside. Or sometimes what you can do, right, you can attach these tiny magnetic nanoparticles to the bubbles and then physically pull the bubbles through the body with a giant external magnet. How wild is that? And I mean, insane. I want to be the drug driver with the magnet who's just like, and I'm going to put that here, I'm going to put that there.

So when you get them to the right part, when you as the drug driver get there, then all you do is you beam ultrasound waves at the tumor so the bubbles end up vibrating so much that they burst. And then the drug gets released at exactly the site of the cancer cells. This is like hyper-targeted drug delivery, keeping your healthy cells safe so that you end up with less side effects. And by the way, we're at the stage now where this successfully treats some cancers in the lab, and they're now preparing to launch this in clinical trials. It's very exciting. But there's one other big challenge. Okay, so you can drive these drugs where you want them. That doesn't mean they can get through the gates that have been erected. Because although these bubbles are tiny, I mean, a fraction of a grain of salt, guess what? Some things in our body are protected against even things that small, like the brain. brain tumors are a huge challenge for drugs because our brains are surrounded by this.

It's basically this tight locked cellular bodyguard chain. It's called the blood brain barrier. And it stops a lot of drugs from getting in. Even if they're in a bubble, they're still too big. So to give you a sense of how tight this blood brain barrier is, you can only fit something that is smaller than seven molecules of salt. Okay? Not a little like piece of a piece of a salt. No, seven molecules of sodium chloride. That's it. And how many are there in a grain of salt? I mean, it's a lot more than seven molecules.

A single grain of salt contains about a quintillion molecules. That's not a billion. That's a billion billion. And we can only get seven of them through. So what do you do? Well, Cancer Research UK scientists have a new idea, a solution here bubbling up. up in their minds and their work. So the drugs are often too big to get in. No problem. Let's use bubbles, not to transport them in, but to open up that blood-brain barrier. So you take micro-bubbles, just empty micro-bubbles, send them up to that blood-brain barrier and then blast them with a beam of ultrasound, which is sound that's just too high for us to hear. And that causes the bubbles to wiggle around. It causes them to expand and contract. And that expansion and contraction can actually open up a larger opening in the blood-brain barrier for the chemotherapy drugs to get into the brain where they're needed. You know what it's like? It's like a heist movie, okay,

but like too small to see. It's breaking into the vault. Meking in through the vault. Yeah, but it's breaking into the vault. You're too big. Not if you dance. Not if you have scientists with ultrasound exactly formulated to wiggle you. Stretching you and squeezing you. exactly the right way. Cancer Research UK is launching clinical trials to test micro bubble delivery of chemotherapy to brain tumors in children and young people right now.

And this could offer a vital treatment for young patients who lack options. And this gives children and young people more moments with their loved ones. So the point is, though, that by backing bold ideas from the laboratory to the clinic, Cancer Research UK is helping develop better, more tailored treatments.

Right. And that means that they work for more people for people with more types of cancer with fewer side effects, crucially. In fact, Cancer Research UK's work has played a role in more than half of the world's essential cancer drugs. That's right. Cancer research that's happening today will change the future of cancer medicine, including for hard-to-treat cancers. And by tackling the biggest challenges, more people can live longer, better lives. For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit canterresearch.uk.org

forward slash rested science. Trevor emailed us asking, how often do coincidences occur? What is the weirdest coincidence in history? How often do we mistake coincidence for fact? And are they always mathematically explainable? Trevor, that's like seven questions in one. And I like it a lot.

I'm here for the layering of questions. Okay, I've got what I think is a really good submission for the weirdest coincidence. So a friend of mine, David Spiegelhuter, who is a Cambridge mathematician, one of my colleagues, he did this whole entire project on coincidences where he got people to submit their coincidences. Because I think that when you, you know, if you talk to the mathematicians or the statisticians, they will say that actually there's a few simple laws behind this. One is the law of truly large numbers. If you try something enough times, even if it has a very small chance of coming true, that actually

it becomes a statistical inevitability. So a different Cambridge mathematician Littlewood, he was around about 100 years ago, really amazing mathematician Littlewood was. But he was like, okay, well suppose a miracle event is, happens one in a million, it's a one in a million event, which sounds impossibly rare. But if you're awake for eight hours a day, like looking for, you're out and about for eight hours a day and you experience, you know, one distinct event every second. Littlewood's life was apparently more interesting and exciting than nine. But you'll rack up a million events every 35 days, you know? And even if you have half that or quarter it, you're talking about one and a million events that will happen a couple of times a year, you know? And I think that in a lot of

ways, that is the way to think of things, is that you are essentially rolling the dice every moment of your life. You are allowing the possibility for a coincidence to happen every moment of your life. All the same, some of them are incredible. So David Spiegelhowter in this project, ask those of people to submit their greatest coincidences. And my favorite one by a long stretch is about Ron Biederman's trousers. He tells this much better than I do, by the way. But essentially, somebody wrote in with this coincidence and they verified it and fact-checked it and it's absolutely true. There was a backpacker called Doug. He was the one who wrote in.

And he was working in Miami when all of his possessions were stolen during this Greyhound bus trip. And he literally had nothing apart from what he was wearing. And so when he went back to his hostel, there was this New Yorker called Ron Biedeman. He was very kind, took pity on him, had some spare clothes and then gave him. this pair, this shirt, sorry, this shirt that had like these very, these kind of very broad, red dull stripes. This is Ron Biedeman's shirt. Anyway, Doug, he eventually returns to the UK. He stores the shirt in this box. In his attic, he doesn't think of it at all. Two years later, Doug is heading to London and he needed some temporary clothes to wear. So he gets this shirt out of

his attic. He puts the shirt on and he's at this backpacker's hostel in Earl's Court. And he goes down for dinner and he starts talking to this girl who was sitting opposite him and she said that she just got back from from a hostel in Israel and then Doug who was making conversation was like, oh, I knew this guy from New York who spent a lot of times in hostels and had been in Israel as well and, you know, I think he like he'd been around that area and she was like, oh my gosh, I know him. Do you mean Ron Biederman? She was like, and he's like, yeah, I do. I do mean Ron Biderman. So they had this like strange connection and the girl was really stunned. And then Doug says, oh, I always remembered Ron Biedeman

because he gave me the shirt that I'm wearing right now and then she is like, you are kidding me because he gave me a pair of trousers that I am currently wearing and she stands up and they are wearing the matching set, the matching shirt and trousers combo that Ron Bideman gave both of them in completely different countries,

one in Miami, one in Israel, they met in London. That's good, that one. That's good. I'm kind of not. that amazed by it, Hannah. I guess maybe I'm thinking about it too much. And I'm like, these people are clearly backpacking around and staying at hostels all the time. They're running into a lot of people. And the kind of person who's going to lend you their shirt or give you their shirt is a very social person who's going to be remembered and give a lot of gifts around.

Like, you're talking about two years later, there's a lot of time for you to run into someone else who knows the same backpacker you did and was also a recipient of their largesse. Well, there's also, there's also how many backpackers are there in the world? How many opportunities are there in the world? There's sort of a survivorship bias to these stories, because the ones that are really extraordinary end up being the ones that are told over and over and over again. Oh, for sure. Yeah, here's a, here's a coincidence, just if you don't mind me telling you a little quick one. Please. Our neighbors, one of our neighbors, we hadn't really met, for like a year.

We just never saw them. And just like last week, my wife saw a woman outside the house and was like, oh, hey, how's it going? What's your name? And the neighbor said that her name was Marty. And my wife is like, oh, that's so similar to my name. My wife's name is Marney, like the Hitchcock film, M-A-R-N-I-E. Marnie. So Marnie and Marty.

Turns out they both have husbands named Michael. So we've got Marnie and Michael and Marty and Michael. That's amazing. That's amazing. That's one type of coincidence that you could have discovered with your neighbor, but maybe it could be that you both went outside and you were both wearing the same pair of shoes. Or it could be that your daughters have the same name or that your daughters were born on the same day. Right, right.

The number of different possibilities that you would accept as a strange coincidence is gigantic. The thing I like to think about is of all of the times that I've met my, you know, my neighbor when I was in Kenya, right? And I saw them in Kenya and was like, wow, this is weird. For all of those times, I like to think about the much greater number of times that I must have just missed somebody. I'm just like a near-miss coincidence. Yeah. And if you could only calculate those, those I think would really blow you away. Yeah, I've had this idea for a while. Ever since I saw signs, you know, that, that, like, alien movie. Right. But coincidences can be scary. And I think that movie must involve some coincidences or something, because I thought there should be a horror film where what's scary is that a bunch of coincidences start happening.

No one gets hurt. It's just like, wait, why is everything working out? Why is everything related? What is going on? That that could be really unsettling. I need to watch it. I haven't seen it. I haven't seen it in so long.

but I remember being inspired to do like a whole horror film about coincidences because in signs, coincidences are part of the story. Let us know in the comments. Leave us a lot of comments. Please do. Tell us your coincidences. I would like to, I genuinely would like to see them. I would love to hear those, yeah.

Absolutely. Yes, thank you. That would be great. All however many hundreds of thousands of you that watch this, please tell us your coincidences. There'll be coincidences between them. You know what I mean? If I've ever what's got, anyway.

So yeah, leave them in the comments below and continue emailing us questions. We love these. And one of these days, I will be able to interact with you on Reddit. So join us there at R slash the rest is science. What I'm going to do to all of the people who've written coincidences in the bottom was I'm just going to go through in everyone and comment, yeah, law of large numbers. Yeah, law of large numbers over and over and over again. We will explain every single one of them.

Well, Hannah will. I don't promise to. I'll see. If there's any that I can't explain, then we'll definitely include them. I'm happy to be proved wrong. I'm happy to be proved wrong, as ever. As always, please do send us in your questions. Your coincidences, hey, why not?

To the rest of science at goahanger.com, and we will see you next week. See you later. Real Canadian Superstore has everything you need this back-to-school season. Save on lunchbox savers like Ziggy's sliced delimed products for always 375. And get life brand pure Vita shampoo or conditioner for $8 each. At Real Canadian Superstore, when you're ready, we're ready. the whole world and more.

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