transcript

Speaker 1:
[00:02] So this weekend, I went for a hike through the beautiful countryside where I grew up, which as a teenager, I couldn't have cared less about, and certainly wouldn't have walked through, for no reason. My reason as an adult is that it's bluebell season. These beautiful plants carpet the woodland in this violet mist. And on my way to admire the scene, I walked up hills and across fields to reach the woods. There was an abundance of greenery, but I couldn't help but notice how much of the landscape has been shaped by humans. Chalk pits giving way to ploughed fields where sheep grazed in medieval times. I climbed to the top of a hill with a church on it and looked back from it. And from a distance, it seemed to reduce the human influence. I feasted on the view of the rolling hills with enough woodlands to hide our human footprint, the quarries, the buildings, the roads. I was almost immersed in nature. I say almost because there was the inevitable chatter from the hundreds of fellow Bluebell lovers who were all noisily out enjoying the same spring day. I'm Marnie Chesterton from the BBC World Service. This is Unexpected Elements. And I'm pleased to say that right now, I'm glad not to be alone, because I need my team of science broadcasters to help me sift through the science today. So, in Accra, Ghana, his first time on the show, Dr. Emmanuel Samani, Health and Science Journalist, and Biomedic. Welcome, Samani. We're delighted to have you here.

Speaker 2:
[01:52] Thank you very much.

Speaker 1:
[01:55] And over in Bucharest, Romania, it's tech journalist Andrada Fiscutean. Welcome back, Andrada.

Speaker 3:
[02:02] Buona mani. Hello.

Speaker 1:
[02:03] Listen, this is the show that looks to the news for inspiration and runs quite often in unexpected directions into a world of science. And it's all thanks to one initial story from the headlines. So, I've been talking so far about the impact of human activities on the environment. And that leads us to the news story, which started 40 years ago in what is now Ukraine. Take a listen to this.

Speaker 4:
[02:33] On April 26th, 1986, a nuclear reactor in Chernobyl exploded.

Speaker 5:
[02:38] First one explosion, then another.

Speaker 4:
[02:40] Spreading radioactive material over a vast area.

Speaker 6:
[02:44] I remembered that night, some noise like crawling sunder.

Speaker 7:
[02:48] Dozens would die in the immediate aftermath.

Speaker 8:
[02:50] The weeks following, just over 100,000 people were evacuated from their homes, many of them never to return.

Speaker 1:
[03:00] Yes, it's the 40th anniversary of the Chernobyl nuclear disaster caused by one of the reactors exploding at the power plant in Ukraine. Decades on, it remains one of the world's worst nuclear disasters. That is our starting point. We've got a whole show to look at the science stories. Where do we start, though, Andrada?

Speaker 3:
[03:23] Well, one thing that fascinates me about Chernobyl is the recovery we've seen from plants and animals in that area.

Speaker 1:
[03:31] Yes, so, far from being a nuclear wasteland, the area of contamination is one of Europe's largest nature reserves. And I think fewer people mean that not only are the wolves thriving, but so are the red deer, the elk, the roe deer and the wild boars.

Speaker 3:
[03:50] And also the fungi at Chernobyl. I think are doing excellent. Have either of you seen photos of Chernobyl's Unit 4 reactor building? And if you've seen those photos, have you noticed walls with patches of dark mould?

Speaker 1:
[04:08] I mean, the exploded reactors, astonishing. I can't say I ever noticed the mould.

Speaker 3:
[04:13] I do have a photo for the two of you. It's a picture of the shelter that was taken in the 1990s. The shelter is that structure that was built over the damaged reactor. And if you look at it closely to the right, you can see some fungal growth on the wall.

Speaker 1:
[04:33] It just looks like, you know, a sort of neglected building with black mould growing on it.

Speaker 3:
[04:38] Yeah, exactly. And I came across the photo in a research paper. The paper is called Fungi from Chernobyl. And the lead author is Nelizh Danuva. She's a Ukrainian researcher who did groundbreaking work on Chernobyl fungi. So those dark spots you can see on the wall are made up of several species of fungi. But the most famous one is Cladosporium spherosporum. It was first described in 1886, so exactly a century before the disaster. And back then scientists saw it on decaying plants. But what's interesting is that this fungus and a few others appear to tolerate extremely high levels of radiation.

Speaker 1:
[05:30] I'm never surprised that fungi can do amazing things. They are quite a bizarre kingdom. Do we know why these fungi can tolerate radiation so well?

Speaker 3:
[05:39] Well, remember I said dark fungi? That color comes from a pigment called melanin. And you and I have some melanin as well. And it helps protect us from UV radiation from the sun. Some researchers believe that the high level of melanin in this fungi almost acts like a shield against the radiation.

Speaker 1:
[06:04] That's very cool. And it reminds me of these algae that have started growing on the Greenland Glacier. They are this very odd color. They survive the harsh UV by having deep purple melanin disks in their surface. Sadly, being dark means that they hold more heat, which accelerates the melting of the glacier. Anyway, I'm getting us off topic. Samani, have you heard of these radiation tolerant fungus?

Speaker 2:
[06:34] Yeah, and that's where it almost sounds counter-intuitive because the idea that something could not just survive the radiation but potentially use it is really challenges how we think about life and energy sources. And so it's incredible if you ask me.

Speaker 3:
[06:56] And to your point, it gets even stranger because there is a possibility that some fungi don't just tolerate radiation well, they might actually feed on it.

Speaker 1:
[07:08] Okay, so you're saying possibility and might here. So just to pick up on those two words, because this is huge, if true, territory, right? I mean, how might that even work? And has this been proven?

Speaker 3:
[07:22] Not quite, but microbiologist Nellie Zydanova, I was mentioning her earlier, she published a few papers that suggest that. And she noted that fungus she and her team found in the soil in Chernobyl seemed to grow toward radiation. Then, in 2007, radio chemist Ekaterina Dadachova released a paper arguing that fungal growth actually increased in the presence of radiation, and that melanized fungi appeared to use radiation to drive their metabolism. So, in other words, they appear to feed on it.

Speaker 1:
[08:03] But this is still contested, right?

Speaker 3:
[08:06] Yeah, it's still more of a theory. Scientists have observed that this fungi can benefit from radiation, but the exact mechanism, so how melanin might be involved in their metabolism, is not yet fully understood.

Speaker 1:
[08:22] I mean, if it is ever fully understood, or at least mostly understood, we will certainly let listeners know here, because that would be amazing, right? You could just chuck the fungi in it and let it clean up the nuclear leaks by just turning it into more fungi. Anyway, thank you, Andrada, for that story on highly radiation-tolerant and possibly radiation-eating fungus. So Samani, we've just heard about radioactive fungi. Where do you want to take us next?

Speaker 2:
[08:58] Staying with radiation, but taking a slightly different direction. When you hear about radiation in a medical context, what comes to mind?

Speaker 3:
[09:06] So, Samani, I had my teeth x-rayed last month. So that's an example of radiation being used in medicine. And a second example would be cancer treatment, right?

Speaker 2:
[09:20] Absolutely. So, because one of the uses I find really interesting is how we use radiation not just to treat a disease, but actually how to detect it. And here's where radioisotopes come in.

Speaker 1:
[09:36] Okay. So, what are radioisotopes?

Speaker 2:
[09:40] Alright. So, when we hear of radioisotopes, these are tiny amounts of radioactive material that are introduced into the body, usually through an injection. And what they do is to move through the body and basically highlight the activity. So, for example, where you have cancer cells...

Speaker 1:
[10:02] Okay. And why do they work well for cancer?

Speaker 2:
[10:05] Right. So, how they work is that you introduce a very small amount of the radioactive substance into the body, attached to something the body already uses, like glucose or sugar, for example. And because we know that these cancer cells are more active, they tend to take up more of the substance. So, case in point, the glucose that we spoke about. And as the radioisotope decays, it gives off what we call signals, basically tiny bursts of energy that then scanners can then detect. So, what you're basically doing is that you're basically mapping out where these cancer cells are in the body with these radioisotopes.

Speaker 1:
[10:51] Samani, where do radioisotopes come from? Where's the shopping list? Where do we get them from?

Speaker 2:
[10:57] Oh, right. So, most medical radioisotopes are produced in nuclear reactors or what we call cyclotrons.

Speaker 1:
[11:07] So, you're in Ghana. Where's your local supplier?

Speaker 2:
[11:11] Because these are very controlled substances, it's not very easy to get it, but it's from a very tight global supply chain. So, from America, from Europe, but within Africa, it's quite tight.

Speaker 1:
[11:25] I know that radioisotopes hit our headlines a couple of years ago because we had a shortage, a potential shortage of them. I think we don't have our own supply chain, we don't manufacture them domestically.

Speaker 3:
[11:36] One thing I keep thinking about when it comes to technology and medicine and how they evolve is that famous quote that says that the future is here, but it's not evenly distributed yet. It feels like there are certain places around the world and certain communities that do not benefit equally from the research. I think it would be also important to make this technology available for everyone, not just for a selected few.

Speaker 1:
[12:05] Well, thank you, Samani, for bringing this area to the table. Thank you, Andrada, for the future is unevenly distributed. That's a great quote. So, we have travelled from fungi that not only survive but thrive near the reactor site to the ways in which radiation can help us diagnose and treat cancer. Listeners, do you have any particular stories on either of those topics that you would like to share? Is there anything you would like us to investigate in this area? The email address is unexpected at bbc.co.uk or you can send us a WhatsApp message. Our number is plus 44 330 678 30 80. Now don't be going anywhere. Next up we're going to find out about something called Atomic Gardening. That's coming up after this.

Speaker 6:
[13:01] Hello, it's Alice here and it's time for the Unexpected Elements Quiz. On the recent Artemis 2 mission, four astronauts travelled around the far side of the moon and then back to Earth over a period of 10 days. In space, astronauts are exposed to greater radiation levels than on Earth, thanks to cosmic rays and solar particles. But did you know that some of our favourite foods are radioactive? For example, bananas. So, I want to know, roughly how many bananas worth of radiation were the Artemis 2 astronauts exposed to during the mission? A. 30,000 bananas, B. 300,000 bananas, or C. 3 million bananas. Again, how many bananas worth of radiation were the Artemis 2 astronauts exposed to? A. 30,000 bananas, B. 300,000 bananas, or C. 3 million bananas. I'll let that bend your brain for a little while, and I'll be back later with the answer.

Speaker 1:
[14:00] You're listening to Unexpected Elements from the BBC World Service, where the 40th anniversary of Chernobyl has us talking about curious corners of nuclear science. Back in the mid 20th century, there was an optimistic buzz about nuclear energy and the ways it could be harnessed for good. And one way this manifested was through the practice of atomic gardening. Now, I never heard of this before we started the show, and I'm pleased that someone who knows a lot more about this is here to tell us. Helen Anne Curry is Professor of the History of Technology at Georgia Institute of Technology. Welcome, Helen.

Speaker 9:
[14:41] Thank you so much. It's a real pleasure to be here.

Speaker 1:
[14:44] So, atomic gardening, what is it and how did it originate?

Speaker 9:
[14:49] Well, I think usually when people refer to atomic gardening, what they're referencing is this idea that it might be possible to use nuclear technologies or radioisotopes to create changes in plant varieties.

Speaker 1:
[15:03] Atomic gardening does sound quite domesticated. It sounds like it was people's back gardens. Is that the setup?

Speaker 9:
[15:12] So, in the late 1940s and then through the 1950s, in the United States, you have very official atomic agricultural research programs, one at a national nuclear laboratory called Brookhaven National Laboratory, another one next to the Oak Ridge National Laboratory in Tennessee. So, we might think of those as the established research infrastructure. But then, that area of research, and especially the newspaper and magazine stories that were written about the idea that radiation could be used to speed up evolution to create new variation at intense rates, that it would have these effects on agriculture, of course, spurred on interest in other places. And people found ways to tap into that. And the main way was through the production of what were called atomic energized seeds that had been exposed to radiation generated either by radioisotopes or within a nuclear reactor that could then be sent to home gardeners who could kind of carry out these experiments for themselves.

Speaker 1:
[16:20] And there were these things called gamma gardens. Can you tell me about them and are there any of them still left?

Speaker 9:
[16:27] So the gamma garden was an installation developed for conducting research on the effects of radiation on growing plants especially when exposed to chronic radiation. And how it worked was that plants were planted in concentric circles around a source of cobalt-60, which would emit gamma radiation. But the cobalt-60 could be raised or lowered into a chamber at the center of the field so that when workers were in the garden, they could be sheltered from the gamma irradiation. But then when they left, the source would be raised from the center of the field and essentially kind of continuously emit radiation that would be felt by the plants in the fields at varying degrees depending on how far they were planted from the central source.

Speaker 1:
[17:17] I was going to ask, it makes gardening sound like an incredibly dangerous occupation.

Speaker 9:
[17:23] It certainly does. There's also a kind of incredible account of the source getting stuck at one point in time at the top of the pole, and then needing to have an expert marksman come in and sort of shoot the cable that keeps the source aloft. So yes, definitely a danger. There's definitely safer methods of plant breeding. But of course, one of the things that the researchers were doing at this period of time was that they would investigate what kinds of genetic and chromosomal and other biological effects you would see as a result of different kinds of radiation over different periods of time, trying to really sort out what the effects of radiation were for different parts of the plant, again, over different periods of time with different kinds of radiation. The scientists, I think, in many cases would have insisted that their research was about understanding the effects of radiation and that the plant breeding was a kind of add-on to that.

Speaker 1:
[18:23] And for humans, the mutations that radiation causes to us tend to be a bad thing. But are you saying things work differently in plants? It just kind of speeds up evolution?

Speaker 9:
[18:39] No, I think what I'm saying is that that was the claim. Something that's especially easy to see when you study it over a long period of time is that it never panned out the way that researchers promised. So they promised that they would speed up evolution and that they would generate new varieties of plants at an increased pace. But of course, the technology didn't deliver in that way.

Speaker 1:
[19:01] So did anything good come out of atomic gardening?

Speaker 9:
[19:06] You can absolutely find accounts of different plant varieties that trace their origin to radiation mutation. I think there's a variety of grapefruit. There's an atomic peanut that is one of the early products, a claim to be a more vigorous plant. But of course, in comparison to the products of more conventional breeding programs, not using radiation-induced mutation, they're just a tiny handful.

Speaker 1:
[19:37] Did these experiments then count as a success because they taught us about radiation and genetic mutation more generally?

Speaker 9:
[19:46] That's an interesting question. You're right that the trajectory that did shape scientific knowledge in different ways was about charting these more basic effects, right? Understanding the tolerance levels or not of plants to different kinds of exposure and maybe in some ways contributing to this larger understanding that we have of just how dangerous and devastating exposure to radiation can be.

Speaker 2:
[20:13] I wanted to ask if there could be any unforeseen long-term effects regarding some of these crops that have been modified with radiation. Is there a chance of long-term side effects?

Speaker 9:
[20:26] The irradiated seeds don't remain radiative themselves. They're not hazardous. When you hear about people growing plants or seeds that were irradiated, it's not that they themselves were exposed to radiation as a result of that. I think you're maybe asking a question though about, are there genetic effects that might have been damaging or might somehow be deleterious to consumers of a product? And I think there's no evidence of that.

Speaker 3:
[20:54] Helen, you mentioned a little bit earlier that this technology did not deliver. I was wondering if there are lessons to be drawn from the history of atomic gardens.

Speaker 9:
[21:05] In thinking about the history of genetic technologies and how those developed over time and the claims that are made about them, the first thing that I think about is the extent to which those claims have been made over time. They started to be made in the early 20th century about Mendelian breeding. It would be more precise. It would be more efficient. We see that repeated with x-rays, with certain kinds of chemical treatments. We see it repeated in the atomic breeding era. And then in the transgenic technology era and then of course today. And each of these technologies does bring something new and different and create greater understanding and new possibilities. But something about that narrative is very repetitive. And so what I hear is not the excitement about something new. I hear the sort of same old story.

Speaker 1:
[21:50] Helen, we're going to have to leave it there. But thank you so much, Professor Helen Anne Curry, for coming on to Unexpected Elements. And I suspect very few of us will have heard of atomic gardening. So thank you for enlightening us.

Speaker 9:
[22:04] Well, it's been a pleasure to be here and to chat with you all. I appreciate it.

Speaker 1:
[22:11] So the 40th anniversary of the Chernobyl disaster has us pondering whether fungi can feed on radiation. We've discovered why radiation is essential in medicine and why shortages are bad news. And we just discovered about an era where scientists grew gamma gardens to try and use radiation to speed up evolution. But we're not done yet. Coming up, we'll be seeing how biased artificial intelligence could affect your health. We'll be looking at the weird physics of glass. And you'd think it would be pretty straightforward to work out how many people died as a result of the Chernobyl disaster. Prepare to be surprised. Stay with us. This is Unexpected Elements from the BBC World Service, the show that looks for the science behind the headlines. I'm Marnie Chesterton in Cardiff in the UK, and I'm here with Emmanuel Samani from Ghana, and Andrada Fiscutean in Bucharest, Romania. We've now reached a bit of the show that we like to call Under the Radar, because this is the place where we make space for a science story that maybe hasn't got the attention it deserves. So one of the panel brings something along, maybe from their bit of the world, and gives it a bit of time to shine in the World Service Spotlight. And Samani, you're up today. What story have you got for us? And there will be entirely meaningless bonus points if you can relate it to this week's theme, which is, of course, the 40th anniversary of the Chernobyl disaster.

Speaker 2:
[23:59] Well, Marnie, I'm bringing you a story that sits at the intersection of health care and AI. And I'll try to earn my points by linking it back to radiation in a slightly indirect way. Because just like radiation, AI is one of those technologies that can be incredibly powerful, but also raises questions about the risks and who benefits from it.

Speaker 1:
[24:25] Okie doke.

Speaker 2:
[24:27] AI.

Speaker 1:
[24:28] Ok. AI in medicine. So this is in Ghana, right? How is Ghana using AI in medicine?

Speaker 2:
[24:35] Oh, Marnie, Ghanians and the health care industry is experiencing what I would call an AI overhaul. Because if you look at the doctor-patient ratio and the lack of equipment, etc., AI is plugging a huge gap in that deficit. And so, in terms of the radiotherapy, in terms of where there aren't a lot of doctors to interpret some of these results. So basically, in imaging and hematology, we're seeing AI practically take over, especially in these rural communities. For example, you need a doctor to come read x-rays and there's no doctor on hand. What do you do? AI is there to block those gaps by uploading these x-rays, and the AI will be able to tell you exactly what disease condition this patient might be having. And so, that's how we're using AI in healthcare in Ghana.

Speaker 1:
[25:41] Okay, so I have definitely read that interpreting images is one of those areas where AI is as good as or better than a human doctor, because you can train it on thousands of pictures of, I don't know, dark masses on a lung or a broken wrist or something, and then if you give it another picture, it will say, okay, yes, this is a broken wrist. So that all depends on what you've fed into the model, though, doesn't it?

Speaker 2:
[26:14] Absolutely, and that's where the issues arise, because it's basically what you feed it, and like you indicated, the AI systems or platforms are able to read thousands of images, but unfortunately, it's what you give it is what you get. And so, if you do not feed it with, you know, wholesale data, you have a lot of people who are left behind because their data is not representative, and that's where the issues come in.

Speaker 1:
[26:48] So, Samani, is there a particular example of the bias that might be exposed?

Speaker 2:
[26:54] So, I'll give you an example of the density of breast tissue. So, particularly in Ghana and Africa, when you're using the platforms to read images of denser breast tissue versus that of less breast tissue, the AI platform could sometimes not be able to tell if there might be a cancer cell in the dense breast tissue.

Speaker 1:
[27:22] Are you saying Ghanaian women have denser breast tissue?

Speaker 2:
[27:25] For the most part.

Speaker 1:
[27:26] Okay. And does that mean that they can hide things on scans in the density?

Speaker 2:
[27:33] Absolutely. You've put it quite clearly. So what that means is that the AI, because it hasn't been trained on denser breast tissues, it might not be able to pick up, you know, cancer cells within these denser breast tissues.

Speaker 1:
[27:47] And are there any solutions to this? I mean, you've given me a clear example. Are there any shortcuts, or is this just going to be a case of making sure that these AI have more African images, sort of data fed into them?

Speaker 2:
[28:05] Right, so unfortunately, there is no shortcuts, because if AI is going to plug the loopholes and ensure that everyone is getting the care that they deserve, especially in a lot of African countries where we're trying to be equitable, there is no shortcut. What we can do is to give it as much data as we can. And for pioneers or for individuals who are building these AI systems, it becomes expensive because ultimately what that means is you need to train your AI system on datasets comprising not just on Western data, not just on African data, but on Eastern data as well so that someone in the Philippines who has access to your platform would have the 100% confidence that, hey, even though this AI system was trained or developed in Africa, I can still use it because the datasets which this platform was trained has everyone else in mind. So unfortunately, there are no shortcuts and to make sure that everyone wins, we just have to train it more and more.

Speaker 1:
[29:16] Okay. Well, listen, we do have a tech journalist on the panel. So just going to double check with the tech journalist, Andrada, is there anything that we can do? Is this a common problem in AIs?

Speaker 3:
[29:30] It is, because technology and AI in particular tends to amplify some of the biases that already exist. And my main issue is with the gender gap, because I'm a woman, and historically, the male body was used as the default model. And this means that sometimes women's symptoms can be under-recognized. And it happens even in mundane things, if you want, like heart disease or pain management. And there was a study published a few months ago. Researcher Shahadan Yudin and colleagues looked at 74 datasets used for disease prediction. And they found gender bias in roughly half of those. And heart disease datasets showed the highest levels of gender bias. So this is a huge issue that we need to talk about. And if there are people in technology who have ways of addressing it, I think it's best to address it sooner rather than later.

Speaker 1:
[30:44] Thank you, Andrada. That's worrying. Half the datasets showing gender bias. So thank you, Samani, and thank you, Andrada, and points for everyone for bringing me a story that definitely would have passed me by, even if it's nothing to do with the overall theme, which of course is the anniversary of Chernobyl's nuclear disaster 40 years ago this week. Each week, we at Unexpected Elements receive dozens of WhatsApp messages, postcards, well, a few postcards, mainly emails from our listeners. And we like to make space for them because you guys write some really good stuff into us. Just a reminder, that email address again is Unexpected at bbc.co.uk. So let's have a look through the inbox. Last week, we talked about the killer chytrid fungus, which is infecting frogs around the world at an alarming rate and has led to the extinction of at least 90 species. Now in response, we got lots of messages about different frog conservation projects, including this message from Chris in Australia, who writes, It brought to mind a very cheap, simple and elegant solution being used in Sydney to combat the chytrid fungus that is killing so many frogs. Frog Saunas, that's a fancy name for a pile of bricks with holes in them, which green and golden bell frogs can sit in. And the fungus doesn't like the heat radiating from the bricks as they warm up in the sun. So it kills the fungus. Such a simple but seemingly effective way of helping this frog species. That's great, isn't it? Saunas, what I've learned recently, not just good for humans, good for frogs too. Right, Gang?

Speaker 3:
[32:44] Well, I've never been to a sauna before, but I probably should try it one day. To be honest, hot places are not really my thing, but I could make an exception in this case and see how it goes.

Speaker 2:
[32:59] You definitely should, Andrada. It's quite refreshing if you ask me.

Speaker 1:
[33:02] Andrada, you're in Eastern Europe, which I just associate blanketly with saunas, but maybe you're too far south.

Speaker 3:
[33:10] Yeah, I'm too far south.

Speaker 1:
[33:12] You get actual warm weather.

Speaker 3:
[33:13] Exactly.

Speaker 1:
[33:15] Moving on, I also asked if any of our listeners have frogs on stamps where they live, which was a blatant attempt to try and get more postcards. And Hayden wrote into the show with a lovely stamp from where they live on the island of Jersey, which features a toad or crapo. Andrada, do you want to read the message?

Speaker 3:
[33:38] Sure. So Hayden writes, this crapo is the Western common toad. As you clever people will know, crapo is French for toad, which ties nicely with our Grenuille story and is also used as a nickname for Jersey residents locally.

Speaker 1:
[33:56] I didn't know that. So we were talking about frogs a lot. We did an entire program on frogs, and it was quite biology heavy. And so by the end, I tried to talk about physics, and it turns out that Grenuille is one of those torturously retrofitted acronyms that scientists doing laser physics have given a name to because there's also a type of laser physics called frog, which is a method of optical gating. So there, do either of you have particularly lovely frogs where you are?

Speaker 3:
[34:30] In Romania, we have the European tree frog. It's small and it looks cute. And it got a cute nickname. So in Romanian, it's called Brotocell. It's a diminutive. And although the frog is tiny, its call is quite loud.

Speaker 2:
[34:48] Well, unlike Andrada in Romania, who has a national frog for lack of a better term, not so much here in Ghana, but I'd love to see the frog that Andrada describes.

Speaker 1:
[35:00] Okay, frog outing to Romania. We'll put that on the bucket list. Thank you, everyone, for writing in. And do please get in touch with stories, photos, frog calls, anything. You can email unexpected at bbc.co.uk. And our WhatsApp number again is plus 44 330 678 3080. Next up, the unexpected physics of glass. That's coming up after this.

Speaker 6:
[35:31] Hello, it's Alice again, and it's time for the quiz answer. Earlier I asked you how many bananas' worth of radiation the Artemis 2 astronauts were exposed to. A. 30,000 bananas, B. 300,000 bananas, or C. 3 million bananas. And the answer is B. 300,000 bananas. This is based on the radiation measured on the earlier unmanned Artemis 1 mission. Data is still being collected for Artemis 2, but it should be broadly similar. Radiation exposure is one of Artemis 2's core science questions to help quantify the health impacts of space travel. But don't worry. Astronauts have a career-long radiation exposure limit to reduce their risk, and the Artemis 2 astronauts use less than 5% of their limit on their mission. Well, I hope you're peeling happy if you got that right. And don't be too sad if you slipped up. There will be another quiz next week.

Speaker 1:
[36:30] We've now come to the part of the show where we take a question from a listener and get an expert on speed dial to answer it. It's time for Ask the Unexpected. Yes, we have carved ourselves out a niche to exist where the internet fails to give you a decent answer. And that's what we're here for. So this week's question is from Tuolumbe in Zambia who asks, dear Unexpected, is it true that glass is a liquid? Great question. This is one of those exciting facts that I remember repeating, but I've never bothered to fact check it. But here's someone who can.

Speaker 10:
[37:20] Hello, my name is Paul Bingham. I'm Professor of Glasses and Ceramics at Sheffield Hallam University. And one of my main research areas is glass and its structure, its properties, and most importantly, its applications, how we use it in our everyday lives.

Speaker 1:
[37:36] Perfect. Paul is exactly who we need. So Paul, is glass a liquid?

Speaker 10:
[37:42] Is glass a liquid? I think my answer would be yes and no. Yes, it is a liquid in that it has the atomic structure. If you look at how the atoms that make up the glass are arranged, it has the atomic structure of a liquid. They're not closely packed together in the same way that you would get in a solid. So to that extent, the structure of the glass is like that of a liquid. However, its properties, the way it behaves in the real world, are those of a solid. It's hard. It doesn't flow like a liquid would. You can make a glass out of most things, but what you have to do is you have to cool it fast enough from when it's liquid in the molten state to when it's rigid without it crystallizing.

Speaker 1:
[38:29] Thank you, Paul, for such an answer. And thanks to Alumba for writing in and setting us off talking to Paul in the first place. Now, listeners, if you have a question that's keeping you up at night, do email the team The email address is Unexpected at bbc.co.uk Or better yet, send a message or voice note to our WhatsApp number. That is plus 44 330 678 3080. It's almost the end of this show, which means that it's time for me to take my free pick. It's a story where I join the dots between things that I want to talk about related to this week's theme. One of the first stories I ever did as a radio presenter was for the 20th anniversary of Chernobyl, because environmental charity Greenpeace came out with this study, this report, that suggested that the death toll was at least 200,000 people. Whereas elsewhere, I'd seen scientists maintain that, no, no, no, no, it was three workers who died around the time of the explosion, and then 28 more dying over the next few months of exposure to radiation. Now, you don't need to be an expert in stats to notice that there's a big difference between a few dozen and 200,000 deaths. So I thought what I'd do is take a bit of time to unpick the reasons for those differences and maybe use the extensive BBC archives and see if there's any lessons we can learn about how we calculate difficult to assess impacts. So let's start things off way back in 1996, ten years after the event. Here's my colleague, a very young Roland Pease on Science in Action.

Speaker 7:
[40:30] Radiation has an ugly reputation and inevitably people have been looking out for its effects ever since the accident sent a cloud of radioactive smoke over Belarus and much of Northern Europe. The high incidence of thyroid cancer suddenly apparent among Belarusian children confirms people's fears. But in fact the effects of low level radiation are poorly understood. It's expected that it harms by damaging DNA, the stuff of genes, and that the resulting mutations can cause cancers.

Speaker 1:
[40:59] The problem is that at high doses it's pretty obvious that radiation is responsible for causing sickness and death. But low doses are what hundreds of thousands of people were exposed to and that's much harder to research, says Professor Gerry Thomas, a molecular pathologist who used to run the Chernobyl tissue bank.

Speaker 11:
[41:20] Yeah, the biggest problem about trying to look for correlations at low dose radiation and excess cancer risk, which is what we're all interested in, is the fact that your health is affected by so many other factors that it's like looking for the needle in the haystack. So there are many other things that have a larger effect on your likelihood of getting cancer than radiation at low levels does. So it becomes increasingly difficult to be sure that there's any effect of radiation at very, very low levels below about 100 millisieverts.

Speaker 1:
[41:52] Professor Thomas, they're mentioning 100 millisieverts. The average American gets exposed to 6 millisieverts a year. I think the average person in the UK gets 2 and a bit millisieverts. This is because there are these tiny doses of radiation everywhere. It's not just bananas. Brazil nuts, that's a big one. Granite, cat litter, places with certain geology. I discovered when digging around that central station in New York is made out of granite. And the levels of radiation coming off that building would be illegal if it were a nuclear power plant. That doesn't mean that they're dangerous. It just means that the safety levels for a nuclear power plant are more stringent, I guess. And that all feeds into what I'm trying to say, which is that radiation is everywhere in small doses. Here's Gerri Thomas again.

Speaker 11:
[42:50] People feel that there is an effect of radiation at any dose level. Whereas in actual fact, at levels below about 100 millisieverts, it's very difficult to be sure because some of the studies show a correlation, and some of them don't show a correlation. But the fact is we've just drawn a straight line and we can't actually do the study that we would like to do in humans because it would be unethical to do it and almost impossible financially to do it, where we looked at people who are exposed to very low levels compared with people who are exposed to no radiation at all, because you can't do that on a planet that's naturally radioactive. It just doesn't make any sense.

Speaker 1:
[43:26] The increased exposure to low levels of radiation definitely does increase your risk of getting cancer. But smoking and drinking and breathing in polluted air, all these are risks. And you cannot say for certain how much of a risk these very low doses of radiation come with. And as Jerry Thomas told me, everything comes with a risk. It just depends on which ones we want to take. So, annoyingly, no, we're probably never going to get a definitive number. So we're going to have to take an educated guess. So I'm turning to someone educated. This is environmental scientist, Professor Jim Smith, who has spent 30 years studying Chernobyl on our Stats Show on the World Service, more or less, from 2019, with his conclusion.

Speaker 5:
[44:21] The best estimate I've seen so far is adding up all those doses to the whole of Europe. So that includes people like us in the UK who got a tiny radiation dose from Chernobyl. It includes the populations of the contaminated area, the evacuees from Pripyat and so on. So the best estimate I've seen is up to 2065 is about 15,000 fatal cancers. So most of those won't have happened yet. If you ask me how many people have died so far, I would put the number in the several thousands.

Speaker 1:
[44:52] I mean, that's as close as we're going to get, some thousands. Andrada, what do you reckon? You've seen the drama series about Chernobyl. Did that give you any insights?

Speaker 3:
[45:04] I have, and I truly appreciate how they decorated the kitchens because they looked just like Soviet kitchen or communist era kitchen that we had in Romania and bonus points for the garbage bin. And what's interesting to me about the Chernobyl accident is that Soviet secrecy around it, of people who knew about a catastrophic situation unfolding and not fully admitting it. And to me, this is the major disaster. It's us not taking responsibility for things that happen in front of us as people.

Speaker 1:
[45:47] Right. So it's interesting to contrast the response from Chernobyl with the response from Fukushima. So after the Fukushima disaster, there was immediate advice not to eat certain things. There was an element of please be cautious and I don't think they had the same spike in thyroid cancers at Fukushima that they had in Chernobyl. Samani, anything to add?

Speaker 2:
[46:17] Yeah, I did see the Netflix show. I thought it was a very powerful representation of what might have transpired. But in other countries and the continents that also need the technology, should also have easier access to make life easier. Because remember, it's not just about the bad events, but we can also have power, we can also have medical treatments out of this is when, to me, that's the take home.

Speaker 1:
[46:48] Do you know what, that is a fascinating point, because a lot of the scientists that I've spoken to about this say, I do ask, so, you know, how do you feel having studied Chernobyl for most of your career? And interestingly, Jim Smith said that when he came to studying Chernobyl for his PhD, he was quite anti-nuclear power. And now having spent decades on it, he's more pro-nuclear power than he was, because he says, you look at the alternatives, and it's things like burning fossil fuels, which come with air pollution risks, and those deaths are also not really something that we talk about enough.

Speaker 2:
[47:33] Yeah, I totally agree. And so that's where we should be looking at.

Speaker 1:
[47:38] Thank you, Samani. I think that is a great note on which to end today's episode. So the 40-year anniversary of Chernobyl, what have we learnt today off the back of that? Well, we've learnt about radiation-eating fungi. We've learnt about medical imaging and atomic peanuts and how to grow a gamma garden. That's a particular favourite of mine. We've had AI biases in healthcare in Ghana, glass physics, frog saunas, and how really difficult it is to work out the future novel's actual death toll. Andrada, any favourite facts from today?

Speaker 3:
[48:17] Definitely frog saunas, Marnie.

Speaker 1:
[48:19] I think that's fantastic. Thank you, listeners, for sending in frog sauna information. Samani, any particular favourites from today?

Speaker 2:
[48:27] I think the whole glass conversation just blew my mind.

Speaker 1:
[48:31] I love that a trend in radioactivity and gardening may have given us a new type of grapefruit. I think that's fantastic. So, we really are out of time. I can't go anywhere without thanking my lovely panel for this week. In Accra, Ghana, first time on this show, didn't he do well? Thank you, Emmanuel Samani.

Speaker 2:
[49:00] Thank you for having me.

Speaker 1:
[49:02] And in Bucharest, Romania, thank you tech journalist, Andrada Fiscutean.

Speaker 3:
[49:06] Thanks, Marnie.

Speaker 1:
[49:08] I'm Marnie Chesterton. The producers were Alice Lipscombe-Southwell and Margaret Sessa Hawkins with Georgia Christie. Do join us next week for more Unexpected Elements.