Discovery

The resurrection quest

<p>‘Can we bring back extinct species?’ wonders listener Mikko Campbell. Well, Professor Fry is pretty excited by the prospect of woolly mammoths roaming the Siberian tundra once more. And everyone is impressed with the science that might make it happen. But Dr Rutherford comes out STRONGLY against the whole thing. Can our expert guests win him over?</p><p>Dr Helen Pilcher shares the tale of Celia the lonely mountain goat, and makes the case for cloning to help protect species at risk of extinction. Professor Beth Shapiro sets out how biotech company ‘Colossal’ plans to engineer Asian elephants’ DNA to make a new group of mammoth-like creatures. And we hear how genetic technologies are being used in conservation efforts around the world.</p><p>BUT WHAT ABOUT T-REXES? Not gonna happen. Sorry.</p><p>Contributors: Dr Helen Pilcher, author of ‘Bring Back the King: The New Science of De-Extinction’, Professor Beth Shapiro from the University of California Santa Cruz, Dr Ben Novak of Revive and Restore and Tullis Matson from Nature’s SAFE.</p>

The puzzle of the pyramids

<p>The Great Pyramids of Giza are awesome feats of engineering and precision. So who built them - and how? Was it a mysteriously super-advanced civilization now oddly extinct? Was it even aliens?</p><p>Nah, course not! Rutherford and Fry investigate how these inspiring monuments were really constructed, and learn about the complex civilisation and efficient bureaucracy that made them possible.</p><p>Professor Sarah Parcak busts the myth that they were built by slaves. In fact, she reveals, it was gangs of well-paid blokes fuelled by the ancient Egyptian equivalent of burgers and beer. And Dr Chris Naunton explains how it was not some mysterious tech, but incredible organisation and teamwork which made it possible to transport massive stone blocks over long distances several thousand years before trucks arrived.</p><p>Dr Heba Abd El Gawad points out how racism led to bizarre assumptions in the history of archaeology, and how those assumptions linger in contemporary conspiracy theories which refuse to accept that Egyptians could have built the pyramids themselves!</p><p>Contributors: Professor Sarah Parcak, University of Alabama, Dr Chris Naunton, Egyptologist and broadcaster, Dr Heba Abd El Gawad, University College London</p>

The Case of The Blind Man's Eye

<p>Close your eyes and think of a giraffe. Can you see it? I mean, *really* see it - in rich, vivid detail? If not - you aren’t alone!</p><p>We’ve had scores of messages from listeners who report having a ‘blind mind’s eye’. They don’t see mental images at all and they want to know why. Jude from Perth wants to know what makes her brain different, and Diane from Scotland wonders whether it affectes her ability to remember family holidays.</p><p>Our sleuths learn that this is a condition recently termed ‘aphantasia’. They meet the chap who came up with the name, Professor Adam Zeman, a neurologist from the University of Exeter, and quiz him on the brain mechanisms behind this mystery.</p><p>Professor Julia Simner - a psychologist who, herself, doesn’t see mental images - shares the surprising research into how aphants differ slightly from others in a range of cognitive skills. We also hear about the world class artists and animators who can’t visualise - but can create beautiful, imaginary worlds.</p><p>Philosophy professor Fiona Macpherson from the University of Glasgow, deepens the mystery: perhaps this largely hidden phenomenon is behind some of the most profound disagreements in the history of psychology. Our mental experiences are all very different - maybe that’s why thinkers have come up with such different theories about how our minds work.</p><p>Search for the “VVIQ” or Vividness of Visual Imagery questionnaire to take the test yourself. Look for “The Perception Census” to take part in this massive online study of perceptual variation. And look up the 'Aphtantasia Network' if you're curious to find out more.</p><p>Presenters: Hannah Fry and Adam Rutherford Contributors: Professor Adam Zeman, Professor Julia Simner, Professor Fiona Macpherson</p>

Our Microbes and Our Health

<p>We are a teeming mass of interconnected microbes and the impact of this microscopic universe on our health, our minds, even our moods, is profound.</p><p>Made in collaboration with Wellcome Collection, Claudia Hammond and an expert panel explore one of the fastest moving areas of science and what it means for modern medicine. </p><p>Recorded in front of a live audience at Wellcome’s Reading Room in London, Claudia discovers how our microbes could be harnessed to improve our mental and physical health. </p><p>And along with the scientific insights, there are important answers to questions everybody wants to know the answer to, such as why some peoples’ “emissions” smell so badly and how having a dog or cat enriches your microbiome.</p><p>On stage with Claudia are immunologist Professor Sheena Cruickshank from the University of Manchester, microbiologist Professor Glenn Gibson from the University of Reading and neuroscientist Professor John Cryan from University College Cork in Ireland.</p><p>Produced by: Fiona Hill and Elisabeth Tuohy Studio Engineer: Bob Nettles and Emma Hearth</p><p>Image: Scanning electron micrograph (SEM) of bacteria cultured from a sample of human faeces. Credit: Steve Gschmeissner/Science Photo Library/Getty Images</p>

Judith Bunbury: Unearthing the secrets of Ancient Egypt

<p>Think Sahara Desert, think intense heat and drought. We see the Sahara as an unrelenting, frazzling, white place. But geo-archaeologist Dr Judith Bunbury says in the not so distant past, the region looked more like a safari park.</p><p>In the more recent New Kingdom of Ancient Egypt, from around 3500 years ago (the time of some of Egypt’s most famous kings like Ahmose I, Thutmose III, Akhenaten, Tutankhamun and queens like Hatshepsut) core samples shows evidence of rainfall, huge lakes, springs, trees, birds, hares and even gazelle, very different from today.</p><p>By combining geology with archaeology, Dr Bunbury, from the department of Earth Sciences at the University of Cambridge and Senior Tutor at St Edmund’s College, tells Jim al-Khalili that evidence of how people adapted to their ever-changing landscape is buried in the mud, dust and sedimentary samples beneath these ancient sites, waiting to be discovered.</p><p>The geo-archaeological research by Judith and her team, has helped to demonstrate that the building of the temples at Karnak near Luxor, added to by each of the Pharaohs, was completely dependent on the mighty Nile, a river which, over millennia, has wriggled and writhed, creating new land on one bank as it consumes land on another. Buildings and monuments were adapted and extended as the river constantly changed course.</p>

The Life Scientific: Clifford Johnson

<p>Clifford Johnson's career to date has spanned some seemingly very different industries - from exploring quantum mechanics around string theory and black holes, to consulting on some of Hollywood's biggest movies; but it makes sense once you understand his ambition of making science accessible to all.</p><p>A Professor in the Department of Physics and Astronomy at the University of Southern California in Los Angeles, Clifford's worked in the United States for decades – but was born in the UK, then spent his formative years on the Caribbean island of Montserrat, before moving back to England to study. Here, he fell in love with quantum mechanics - before moving to the US, where he's broken new ground in finding ways to talk about quantum gravity and black holes.</p><p>Clifford's other big passion is getting as many people as possible engaged with science, making it more exciting, entertaining and most importantly diverse - and it's this attitude that's led to regular work as a science consultant on various TV shows and films; and even a recent cameo in a major movie.</p>

The Life Scientific: Rebecca Kilner

<p>A fur-stripped mouse carcase might not sound like the cosiest of homes – but that is where the burying beetle makes its nest, and where Rebecca Kilner has focused much of her research.</p><p>A professor of evolutionary biology at the University of Cambridge, Rebecca’s work – initially with cuckoos, then more recently with beetles – has shed invaluable light on the relationship between social behaviours and evolution.</p><p>She tells Jim al-Khalili how the beetles' helpfully swift generational churn and mouse-based parenting has allowed her team to study evolution in action, demonstrating for the first time what was previously just evolutionary theory.</p>

The magnetic mystery

<p>Magnets are inside loads of everyday electronic kit - speakers, motors, phones and more - but listener Lucas is mystified. What, he wonders, is a magnetic field?</p><p>Our sleuths set out to investigate the mysterious power of magnets, with the help of wizard physicist Dr Felix Flicker, lecturer in physics at Cardiff University and author of the The Magick of Matter, and materials scientist Dr Anna Ploszajski, author of Handmade.</p><p>They cover the secrets of lodestones, naturally occurring magnetic rocks, how to levitate crystals, frogs and maybe even people.</p><p>Matthew Swallow, the Chair of the UK Magnetics Society, explains why magnets make the best brakes for rollercoasters, and Dr Ploszajski explains how magnetically-induced eddy currents are used to sort through our recycling.</p><p>Finally, Dr Flicker persuades Adam and Hannah that to really understand magnetic fields you have to leave classical physics behind, and go quantum. So our sleuths take a leap into the strange subatomic realm.</p>

The Life Scientific: Tim Lamont

<p>Tim Lamont is a young scientist making waves. Arriving on the Great Barrier Reef after a mass bleaching event, Tim saw his research plans disappear and was personally devastated by the destruction. But from that event he discovered a novel way to restore coral reefs. Playing the sounds of a healthy coral reef entices fish in to recolonise the wrecked reefs. Tim's emotional journey forced him to realise that environmental scientists can no longer just observe. They need to find new prisms with which to view the world and to intervene to save or protect the natural environment.</p>

Bad Blood: Newgenics

<p>Are we entering a ‘newgenic’ age - where cutting-edge technologies and the power of personal choice could achieve the kind of genetic perfection that 20th century eugenicists were after?</p><p>In 2018, a Chinese scientist illegally attempted to precision edit the genome of two embryos. It didn’t work as intended. Twin sisters - Lulu and Nana - were later born, but their identity, and the status of their health, is shrouded in secrecy. They were the first designer babies.</p><p>Other technological developments are also coming together in ways that could change reproduction: IVF can produce multiple viable embryos, and polygenic screening could be used to select between them.</p><p>Increased understanding and control of our genetics is seen as a threat by some - an inevitable force for division. But instead of allowing genetics to separate and rank people, perhaps there’s a way it can be used - actively - to promote equality. Professor Paige Harden shares her suggestion of an anti-eugenic politics which makes use of genetic information</p><p>Contributors: Dr Helen O'Neill, lecturer in Reproductive and Molecular Genetics at University College London, Dr Jamie Metzl, author of Hacking Darwin, Professor Kathryn Paige Harden from the University of Texas and author of The Genetic Lottery: Why DNA Matters for Social Equality.</p>

Bad Blood: The curse of Mendel

<p>In the mid-19th Century, an Augustinian friar called Gregor Mendel made a breakthrough. By breeding pea plants and observing how certain traits were passed on, Mendel realised there must be units - little packets - of information determining characteristics. He had effectively discovered the gene.</p><p>His insights inspired eugenicists from the 1900s onwards. If traits were passed on by specific genes, then their policies should stop people with ‘bad’ genes from having children.</p><p>Mendel’s ideas are still used in classrooms today - to teach about traits like eye colour. But the eugenicists thought Mendel's simple explanations applied to everything - from so-called ‘feeblemindedness’ to criminality and even pauperism.</p><p>Today, we recognise certain genetic conditions as being passed on in a Mendelian way. Achondroplasia - which results in short stature - is one example, caused by a single genetic variant. We hear from Professor Tom Shakespeare about the condition, about his own decision to have children despite knowing the condition was heritable - and the reaction of the medical establishment.</p><p>We also explore how genetics is taught in schools today and the danger of relying on Mendel’s appealingly simple but misleading account.</p><p>Contributors include Dr Brian Donovan, senior research scientist at BSCS, Prof Tom Shakespeare, disability researcher at London School of Hygiene and Tropical Medicine, and Dr Christine Patch, principal staff scientist in Genomic Counselling in the Society and Ethics Research group, part of Wellcome Connecting Science.</p><p>(Photo: Johann Gregor Mendel (1822-1884). Austrian botanist, followed breeding experiments, discovered paired units of heritable characteristics. Credit: Hulton Archive/Getty Images)</p>

Bad Blood: Rassenhygiene

<p>In the name of eugenics, the Nazi state sterilised hundreds of thousands against their will, murdered disabled children and embarked on a programme of genocide.</p><p>We like to believe that Nazi atrocities were a unique aberration, a grotesque historical outlier. But it turns out that leading American eugenicists and lawmakers like Madison Grant and Harry Laughlin inspired many of the Nazi programmes, from the mass sterilisation of those deemed ‘unfit’ to the Nuremberg laws preventing the marriage of Jews and non-Jews. Indeed, before World War Two, many eugenicists across the world regarded the Nazi regime with envious admiration.</p><p>The Nazis went further, faster than anyone before them. But ultimately, the story of Nazi eugenics is one of international connection and continuity.</p><p>With contributions from Prof Stefan Kühl from the University of Bielefield, Prof Amy Carney from Penn State Behrend, Dr Jonathan Spiro from Castleton University, Prof Sheila Weiss from Clarkson University and Dr Barbara Warnock from the Wiener Holocaust Library</p><p>(Photo: German women carrying children of an alleged aryan purity in a Lebensborn selection centre, births by eugenicists methods during World War Two. Credit Keystone-France Getty Images)</p>

Bad Blood: Birth controlled

<p>Who should be prevented from having children? And who gets to decide? Across 20th century America, there was a battle to control birth - a battle which rages on to this day.</p><p>In 1907, the state of Indiana passed the first sterilisation law in the world. Government-run institutions were granted the power to sterilise those deemed degenerate - often against their will.</p><p>In the same period, women are becoming more educated, empowered and sexually liberated. In the Roaring Twenties, the flappers start dancing the Charleston and women win the right to vote.</p><p>But contraception is still illegal and utterly taboo. The pioneering campaigner Margaret Sanger, begins her decades long activism to secure women access to birth control - the only way, she argues, women can be truly free.</p><p>In the final part of the episode, sterilisation survivor and campaigner Elaine Riddick shares her painful but remarkable story.</p><p>Contributors: Professor Alexandra Minna Stern from the UCLA Institue of Society and Genetics, Professor Wendy Kline from Purdue Univerity, Elaine and Tony Riddick from the Rebecca Project for Justice</p><p>Featuring the voice of Joanna Monro</p><p>(Photo: Elaine Riddick was sterilised without her consent, when she was 14, in North Carolina. Credit: Tami Chappell/The Washington Post/Getty Images)</p>

Bad Blood: You will not replace us

<p>"You will not replace us" was the battle cry of white supremacists at a rally in Charlottesville in 2017. They were expressing an old fear - the idea that immigrants and people of colour will out-breed and replace the dominant white 'race'. Exactly the same idea suffused American culture in the first decades of the 1900s, as millions of immigrants arrived at Ellis island from southern and eastern Europe.</p><p>The 'old-stock' Americans - the white elite who ruled industry and government - latched on to replacement theory and the eugenic idea of 'race suicide'. It's all there in The Great Gatsby - F.Scott Fitzgerald's novel set in 1922 - which takes us into the world of the super-rich, their parties and their politics.</p><p>Amidst this febrile period of cultural and economic transformation, the Eugenics Record Office is established. Led by Charles Davenport and Harry Laughlin, it becomes a headquarters for the scientific and political advancement of eugenics.</p><p>By 1924, the eugenically informed anti-immigrant movement has triumphed - America shut its doors with the Johnson-Reed Act, and the flow of immigrants is almost completely stopped.</p><p>Contributors: Dr Thomas Leonard, Professor Sarah Churchwell, Professor Joe Cain</p><p>Presenter: Adam Rutherford Producer: IIan Goodman</p><p>(Photo: Immigrants arriving in Ellis Island, New York, 27 May 1920. Credit: Getty Images)</p><p>Clips: BBC News, coverage of Charlottesville protests, 2017 / CNN, coverage of buffalo shooter, 2022 / MSNBC, coverage of buffalo shooter, 2022 / Edison, Orange, N.J, 1916, Don't bite the hand that's feeding you, Jimmie Morgan, Walter Van Brunt, Thomas Hoier / BBC Radio 4 Great Gatsby: Author, F Scott Fitzgerald Director: Gaynor Macfarlane, Dramatised by Robert Forrest.</p>

Bad Blood: You've got good genes

<p>We follow the story of eugenics from its origins in the middle-class salons of Victorian Britain, through the Fitter Family competitions and sterilisation laws of Gilded Age USA, to the full genocidal horrors of Nazi Germany.</p><p>Eugenics is born in Victorian Britain, christened by the eccentric gentleman-scientist Sir Francis Galton. It’s a movement to breed better humans, fusing new biological ideas with the politics of empire, and the inflexible snobbery of the middle-classes.</p><p>The movement swiftly gains momentum - taken up by scientists, social reformers, and even novelists as a moral and political quest to address urgent social problems. By encouraging the right people to have babies, eugenicists believed we could breed ourselves to a brighter future; a future free from disease, disability, crime, even poverty. What, its proponents wondered, could be more noble?</p><p>The story culminates in the First International Eugenics Congress of 1912, where a delegation of eminent public figures from around the world gather in South Kensington to advocate and develop the science – and ideology – of better breeding. Among them Winston Churchill, Arthur Balfour, the Dean of St Pauls, Charles Darwin's son, American professors and the ambassadors from Norway, Greece, and France.</p><p>But amidst the sweeping utopian rhetoric, the darker implications of eugenic ideas emerge: what of those deemed 'unfit'? What should happen to them?</p><p>Contributors: Professor Joe Cain, Daniel Maier, Professor Philippa Levine, Professor Angelique Richardson</p><p>Featuring the voices of David Hounslow, Joanna Monro and Hughie O'Donnell</p><p>(Photo: Francis Galton (1822-1911), British man of science born in Sparkbrook (England). Ca. 1890. Credit: adoc-photos/Corbis/Getty Images)</p>

Tooth and Claw: Cougar

<p>Hiding in the shadows across the American continents lives a big cat with many names. From puma to mountain lion to panther to cougar, this animal is carnivorous, cunning and uses stealth to silently ambush its prey. Its elusiveness and brutal attacking style has earnt it the reputation of a cold-hearted killer. But behind this façade, hidden camera footage has revealed the cougar is all about caring for their family. And its silent whispering amongst the trees could actually be saving human lives. Adam Hart and guests uncover the mysteries of the ‘ghost of the forest’ and break its merciless stereotype. </p><p>Dr Laura Prugh, associate Professor of Quantitative Wildlife Sciences at the University of Washington, and Dr Mark Elbroch, ecologist and director of the Panthera programme in Washington USA.</p>

Tooth and Claw: Wasps

<p>Why do wasps exist? While many see them as unfriendly bees who sting out of spite, their aggression could be interpreted as a fierce form of family protection. They are hugely understudied and even more underappreciated, with hundreds of thousands of different species carrying out jobs in our ecosystems. Some live together in nests whereas others hunt solo, paralysing prey with antibiotic-laden venom. In abundance, they can destroy environments - outcompeting most creatures and taking resource for themselves - but could we harness their predatory powers to take on pest control? Adam Hart and guests are a-buzz about this much-maligned insect and explore why we should be giving them more credit.</p><p>Professor Seirian Sumner, behavioural ecologist at University College London, and Dr Jenny Jandt, ecologist at University of Otago, New Zealand.</p>

Tooth and Claw: African Wild Dog

<p>As a great African predator and a hot-spot on safari, it is hard to believe that only last century, the African wild dog was considered vermin. It's beautiful coat of painted strokes makes it undeniably distinctive. Yet out in the field, this animal is hard to find. Yes, it camouflages easily against the landscape, but years of persecution, bounties and unintentional trappings means it's now one of the most endangered mammals on the planet. Revelations about its reliance on the pack for protection, predation and parenting means every dog matters in its bid for survival. So how can we further stop numbers dwindling? Adam Hart and guests investigate the tools and tales of the magnificent painted wolf.</p><p>Dr Dani Rabaiotti, zoologist at the Zoological Society of London, and David Kuvawoga and Jealous Mpofu, conservationists at Painted Dog Conservation in Zimbabwe.</p>

Preparing for the next pandemic

<p>Infectious diseases which cause epidemics and pandemics are on the rise.</p><p>Claudia Hammond is joined by an eminent panel of disease detectives, who spell out why the risks are increasing and most importantly, what we can do to predict, prepare and protect ourselves against potentially devastating new outbreaks.</p><p>Will the next infectious disease to wreak havoc across the globe again jump from animals, a zoonotic jump across species? </p><p>Think SARS, HIV, MERS, Zika, Nipah Virus, Lassa Fever, Ebola, Avian Flu, Swine Flu, Mpox and of course the coronavirus that causes Covid-19. </p><p>The panel is unanimous in their plea for recognition that human health is inextricably linked to both animal health and the health of the environment. Without an understanding that we are part of an ecosystem and that climate change and the loss of biodiversity have a direct impact on epidemic and pandemic risk, we’ll struggle to keep ourselves safe they say.</p><p>Claudia is joined by vet-turned-virologist Marion Koopmans, Professor of Viroscience at Erasmus Medical Centre in the Netherlands and head of the Pandemic and Disaster Preparedness Centre; by Tulio de Oliveira, Professor of Bioinformatics, director of the Centre for Epidemic Response and Innovation (CERI) and the KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP) in South Africa and Malik Peiris, Professor of Virology at the University of Hong Kong’s School of Public Health. </p><p>Produced by: Fiona Hill and Elisabeth Tuohy Studio Engineer: Duncan Hannant</p><p>Image: Chickens in Thailand Credit: Wut'hi Chay Si Tang Kha/EyeEm/Getty Images</p>

Tooth and Claw: Komodo dragon

<p>With nicknames like ‘prehistoric monster’ and ‘living dinosaur’, the Komodo dragon has been well and truly judged by its cover. Its gigantic size, razor sharp teeth and deadly attacking power has earned it a vicious reputation. But beneath the scales of this solitary beast are fascinating tales of rapid healing, decoy nests, and virgin births. And as climate change threatens its native Indonesia, can this hostile reptile adapt to living in closer quarters? Adam Hart and guests dig into how a lonely life may be putting the Komodo dragon at risk...</p><p>Deni Purwandana, program co-ordinator for the Komodo Survival Program in Komodo National Park, and Dr Chris Michaels, team leader of Reptiles and Amphibians at London Zoo.</p>

Wild Inside: The Alpaca

<p>Alpacas may have been domesticated for thousands of years but their native lands are the steep hostile mountains of South America where they continue to thrive far from the modern luxuries of animal husbandry. Prof Ben Garrod and Dr Jess French delve deep inside this hardy herbivore to unravel the anatomy and physiology that’s secured the success of this extraordinary member of the camelid family of camels, llamas and vicugna.</p>

Wild inside: The Harbour Porpoise

<p>Prof Ben Garrod and Dr Jess French get under the skin of the harbour porpoise to unravel this enigmatic and shy aquatic mammal’s extraordinary survival skills - from it’s ability to dive for long periods to accurately echolocating its fast moving prey. They join Rob Deaville, project leader for the Cetacean’s Stranding Investigations Programme at ZSL (Zoological Society of London) to open up and examine what makes this animal unique in terms of its anatomy, behaviour and evolutionary history.</p>

Wild inside: Great Grey Owl

<p>One of the world’s large owls by length, the Great Grey Owl is an enigmatic predator of coniferous forests close to the Arctic tundra. It's most often seen hunting around dawn and dusk, when it perches silently at the edges of clearings. But as Prof Ben Garrod and Dr Jess French delve deep inside to understand its true secret to survival, they find the deep feathery coat belies a deceptively small head and body that‘s evolved unbelievably powerful abilities to silently detect and ambush unsuspecting prey.</p>

Wild inside: The Cheetah

<p>Zoologist Ben Garrod and veterinary surgeon Jess French delve deep into some amazing internal anatomy to unravel the secrets to survival of some of nature’s iconic animals.</p><p>They begin with one of the rarities of the cat family – the cheetah, which at just under two metres long, is the world’s fastest land animal capable of reaching speeds of up to 70mph in three seconds. As Ben and Jess reveal, the body’s rear muscles, large heart and nostrils enable it to achieve record breaking accelerations. But over long distances, it risks total exhaustion and predation from larger carnivores and the risk of losing its valuable prey. We hear during the course of this intricate dissection, how it treads a fine line between speed and stamina in the quest for survival.</p>

The puzzle of the plasma doughnut

<p>What do you get if you smash two hydrogen nuclei together? Helium and lots of energy – it's nuclear fusion!</p><p>Nuclear fusion is the power source of the sun and the stars. Physicists and engineers here on earth are trying to build reactors than can harness fusion power to provide limitless clean energy. But it’s tricky.</p><p>Rutherford and Fry are joined by Dr Melanie Windridge, plasma physicist and CEO of Fusion Energy Insights, who explains why the fourth state of matter – plasma – helps get fusion going, and why a Russian doughnut was a key breakthrough on the path to fusion power.</p><p>Dr Sharon Ann Holgate, author of Nuclear Fusion: The Race to Build a Mini Sun on Earth, helps our sleuths distinguish the more familiar nuclear fission (famous for powerful bombs) from the cleaner and much less radioactive nuclear fusion.</p><p>And plasma physicist Dr Arthur Turrell, describes the astonishing amount of investment and innovation going on to try and get fusion power working at a commercial scale.</p>

The Riddle of Red-Eyes and Runny-Noses

<p>Sneezes, wheezes, runny noses and red eyes - this episode is all about allergies.</p><p>An allergic reaction is when your immune system reacts to something harmless – like peanuts or pollen – as if it was a parasitic invader. It’s a case of biological mistaken identity.</p><p>Professor Judith Holloway from the University of Southampton guides our sleuths through the complex immune pathways that make allergies happen and tells the scary story of when she went into anaphylactic shock from a rogue chocolate bar.</p><p>Professor Adam Fox, a paediatric allergist at Evelina Children’s Hospital, helps the Drs distinguish intolerances or sensitivities – substantial swelling from a bee sting, for example - from genuine allergies. Hannah’s orange juice ‘allergy’ is exposed as a probable fraud!</p><p>Hannah and Adam explore why allergies are on the increase, and Professor Rick Maizels from the University of Glasgow shares his surprising research using parasitic worms to develop anti-allergy drugs!</p><p>Contributors: Professor Judith Holloway, Professor Adam Fox, Professor Rick Maizels</p>

The problem of infinite Pi(e)

<p>Pi is the ratio between a circle’s diameter and its circumference. Sounds dull – but pi turns out to have astonishing properties and crop up in places you would never expect. For a start, it goes on forever and never repeats, meaning it probably contains your name, date of birth, and the complete works of Shakespeare written in its digits.</p><p>Maths comedian Matt Parker stuns Adam with his ‘pie-endulum’ experiment, in which a chicken and mushroom pie is dangled 2.45m to form a pendulum which takes *exactly* 3.14 seconds per swing.</p><p>Mathematician Dr Vicky Neale explains how we can be sure that the number pi continues forever and never repeats - despite the fact we can never write down all its digits to check! She also makes the case that aliens would probably measure angles using pi because it’s a fundamental constant of the universe.</p><p>Nasa mission director Dr Marc Rayman drops in to explain how pi is used to navigate spacecraft around the solar system. And philosopher of physics Dr Eleanor Knox serves up some philoso-pi, revealing why some thinkers have found pi’s ubiquity so deeply mysterious.</p>

The suspicious smell

<p>Why are some smells so nasty and others so pleasant? Rutherford and Fry inhale the science of scent in this stinker of an episode.</p><p>Our sleuths kick off with a guided tour of the airborne molecules and chemical receptors that power the sense of smell. Armed with a stack of pungent mini-flasks, professor Matthew Cobb from the University of Manchester shows Hannah and Adam just how sensitive olfaction can be, and how our experience of some odours depends on our individual genetic make-up.</p><p>Dr Ann-Sophie Barwich from Indiana University reveals how most everyday smells are complex combinations of hundreds of odorants, and how the poo-scented molecule of indole turns up in some extremely surprising places.</p><p>With the help of a flavoured jellybean and some nose clips, Hannah experiences how smell is crucial to flavour, adding complexity and detail to the crude dimensions of taste.</p><p>Speaking of food, listener Brychan Davies is curious about garlic and asparagus: why do they make us whiff? Professor Barry Smith from the Centre for the Study of the Senses reveals it's down to sulphur-containing compounds, and tells the story of how a cunning scientist managed to figure out the puzzle of asparagus-scented urine.</p><p>Finally, another listener Lorena Busto Hurtado wants to know whether a person’s natural odour influences how much we like them. Barry Smith says yes - we may sniff each other out a bit like dogs - and cognitive neuroscientist Dr Rachel Herz points to evidence that bodily bouquet can even influence sexual attraction!</p>

The Wild and Windy Tale

<p>How do winds start and why do they stop? asks Georgina from the Isle of Wight. What's more, listener Chris Elshaw is suprised we get strong winds at all: why doesn't air just move smoothly between areas of high and low pressure? Why do we get sudden gusts and violent storms?</p><p>To tackle this breezy mystery, our curious duo don their anoraks and get windy with some weather experts.</p><p>Dr Simon Clark, a science Youtuber and author of Firmament, convinces Adam that air flow is really about the physics of fluids, which can all be captured by some nifty maths. The idea of pressure turns out to be key, so Hannah makes her own barometer out of a jar, a balloon and some chopsticks, and explains why a bag of crisps will expand as you walk up a mountain.</p><p>Professor Liz Bentley, Chief Executive of the Royal Meteorological Scoiety, reveals how the dynamics of a simple sea breeze – where air over land is heated more than air over water – illustrates the basic forces driving wind of all kinds.</p><p>Then everyone gets involved to help Adam understand the tricky Coriolis effect and why the rotation of the Earth makes winds bend and storms spin. And Professor John Turner from the British Antarctic Survey explains why the distinctive features of the coldest continent make its coastline the windiest place on earth.</p>

The Case of The Missing Gorilla

<p>DO WE HAVE YOUR ATTENTION?</p><p>Good! But how does that work!?</p><p>Our intrepid science sleuths explore why some things immediately catch your eye - or ear - while others slip by totally unnoticed. Even, on occasion, basketball bouncing gorillas.</p><p>Professor Polly Dalton, a psychologist who leads The Attention Lab at Royal Holloway University, shares her surprising research into ‘inattentional blindness’ - when you get so absorbed in a task you can miss striking and unusual things going on right in front of you.</p><p>Dr Gemma Briggs from the Open University reveals how this can have dangerous everyday consequences: you are four times more likely to have a crash if you talk on the phone while driving -even handsfree.</p><p>Drs Rutherford and Fry also hear from stroke survivor Thomas Canning, who developed the tendency to ignore everything on the left side of space, despite his vision being totally intact. </p><p>And Dr Tom Manly, from the University of Cambridge’s Cognition and Brain Sciences Unit, helps our sleuths unpack the neuroscience of this fascinating condition.</p>