Alle afleveringen van CrowdScience – pagina 2 van 11

Do tsunamis affect marine life?

14 november 2025 · 27 min

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Tsunamis destroy buildings, habitats and danger to everything in its path on land. But how do they affect life under the water? That's what CrowdScience listener Alvyn wants to know, and presenter Anand Jagatia is searching beneath the waves for answers. Anand meets Professor Syamsidik who is learning about how tsuanami waves are formed to help protect against future disasters. He runs the Tsunami and Disaster Mitigation Research Center at Universitas Syiah Kuala, Indonesia. With him at this state-of-the-art lab is Dr David McGovern, expert in ocean and coastal modelling at London South Bank University. David tells Anand how the energy of a tsunami is spread across the entire water column. To explain the forces at play, Anand chats to Professor Emile Okal a seismologist from Northwestern University in the United States. Tsunami wave can move as fast as 800 kilometres an hour but, despite this, out at sea you might not notice it - but can the same be said for marine life? We follow the wave as it nears land and all that force is contracted and begins to show its might. Professor Suchana 'Apple' Chavanich from Chulalongkorn University, Thailand was one of the first people to swim off the Thai coast after the 2004 tsunami and remembers how coral reefs were battered.
In Japan, after the 2011 Tohoku Earthquake and Tsunami as the water retracted it pulled with it tons and tons of debris into the water. The fishing communities of the Sanriku Coast lost almost everything, their equipment was destroyed and the water was heavily polluted. Anand meets Hiroshi Sato who set up the Sanriku Volunteer Divers, a team of people who dragged the debris out of the water. One of them was diver and journalist Bonnie Waycott who tells her story of witnesses the destruction first hand and trying to rescue the fishing industry with Hiroshi. Finally, we learnt that the effect of modern tsunamis carries far further than people might have imagined. On the west coast of the United States Profes… Lees meer

Are near-death experiences real?

7 november 2025 · 26 min

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In your final moments, they say, you may walk down a tunnel of light. You might rise above your body, watching the scene below before passing into another world. Perhaps you’ll be met by glowing figures, see your life flash before your eyes, or feel a deep, unearthly calm. Lees meer

These are the stories of people who’ve reached the edge of death and returned. They’re not rare, nor random, and they have a name: near-death experiences.

CrowdScience listener Steven in Chile first heard of them during a CPR class and wondered, are they fictitious?

Psychologist Susan Blackmore once had an out-of-body experience as a student in Oxford, UK — floating above herself before soaring over the rooftops and dissolving into the universe. That single moment changed everything. She’s spent her career trying to understand what happened, and she believes such experiences are explainable.

At the University of Michigan in the US, neuroscientist Professor Jimo Borjigin has done what few have dared: record the dying brain in action. Her studies show that even after the heart stops, the brain can produce powerful surges of coordinated activity, bursts that might explain the lights, the tunnels, and the sense of peace. She believes near-death experiences could become one of science’s most intriguing scientific frontiers for research into consciousness.

At University College London in the UK, neuroscientist Dr Christopher Timmermann is exploring similar states using psychedelics, pushing the boundaries between self and oblivion to identify what induces a near-death experience and what we can learn about our consciousness along the way.

Near death experiences, a paranormal mystery or explainable phenomenon?

Presenter: Caroline Steel
Producer: Harrison Lewis
Editor: Ben Motley

(Photo: Gap in the wall - stock photo Credit: peterschreiber.media via Getty Images)

Why do people love horror films?

3 november 2025 · 31 min

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For some they’re the stuff of nightmares, but many of us can’t get enough of horror films. For Halloween, CrowdScience investigates the science of why we enjoy films that scare the living daylights out of us. Lees meer

CrowdScience listener Maria from Taiwan is one of those people who would rather avoid frightening films, yet her husband loves them and is always trying to get her to watch with him. She wants to know why people like her husband are so drawn to horror films.

To try and find out, presenter Anand Jagatia travels to the Recreational Fear Lab in Aarhus, Denmark, which is dedicated to understanding why people frighten themselves for fun. He meets the research lab’s directors Mathias Clasen and Marc Andersen who explain how horror and recreational fear could help us cope better with uncertainty, bond with those we are frightened beside, and perhaps even have some physical health benefits. They also take Anand to a haunted house, called Dystopia, which has used the Recreational Fear Lab’s research to become as terrifying as possible.

And we hear from horror film music composer, Mark Korven, who creates tension and fear using an invention he calls ‘the apprehension engine’. He speaks to BBC Naturebang’s Becky Ripley who has been investigating sounds that scare us and their evolutionary origins.

Presenter: Anand Jagatia
Producer: Jonathan Blackwell

(Photo: Couple watch horror movie with blanket to cover their heads. Credit: WC.GI via Getty Images)

Should we help maggots and caterpillars?

24 oktober 2025 · 27 min

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We all know insects are important, but one CrowdScience listener worries that they don’t seem to have equal billing when it comes to human love and attention. Lees meer

In Scotland’s capital Edinburgh, listener Ruth loves to sit and listen to the birds, the bees and the hoverflies as they go about their daily chores. And it’s got her wondering why bees and butterflies seem to get all the conservation efforts. What do we need to do to protect butterflies as less beautiful caterpillars, and ladybirds as less glamorous larvae? Are people even aware that insects exist in multiple stages of a lifecycle, and that around the world, insect populations are facing perilous levels of decline.

Presenter Alex Lathbridge is on a mission to identify the other unsung insect heroes. Along the way we meet Dr Caitlin Johnstone and Dr Nick Balfour at the Royal Botanic Gardens Edinburgh, who help listener Ruth find out about the lifestyles and lifecycles of hoverflies.

We meet the midge that pollinates cocoa crops in Ghana, as well as Dr Tonya Lander from Oxford University and Dr Acheampong Atta-Boateng from the University of Arizona who have been studying them. And Marc Vaez-Olivera from the company Polyfly introduces us to the billions of hoverflies helping to double avocado yields in Spain.

We also learn what we can all do to help keep insects in our gardens… even if that may involve sacrificing a cabbage or two.

Presenter: Alex Lathbridge

Producer: Marnie Chesterton

Editor: Ben Motley

(Photo: Caterpillar eating flowering plant with pink background - stock photo Credit: Raquel Lomas via Getty Images)

Can we record our senses?

17 oktober 2025 · 26 min

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How would you record a special moment? Maybe you could take a photograph, film a little video, or record some audio. We have lots of ways of recording what life LOOKS and SOUNDS like, but is the same true for the other senses? What if you wanted to record the smells that greet you on entering your favourite restaurant? Or record the way your loved ones hand feels in yours? Lees meer

These are the questions on the mind of listener Aravind, from California in the USA. He wants to know if there are any ways of recording and reproducing sensory experiences like taste and smell, or physical touch.

Anand Jagatia is on the case, and is smelling, tasting, and quite literally FEELING his way to the answer. From a multi-sensory movie experience in Valencia, Spain, to the fascinating history of the pioneers of ‘scented cinema’, through to the ground-breaking “haptic technology” which is enhancing the capabilities of our sense of touch. Both for us, and for the robots which do the jobs we don’t want to.

Presenter: Anand Jagatia

Producer: Emily Knight

Editor: Ben Motley

(Photo: Woman making ASMR sounds with microphone and perfume on yellow background, closeup - stock photo. Credit: Liudmila Chernetska via Getty Images)

Are atoms immortal?

10 oktober 2025 · 26 min

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Atoms are the building blocks of our world. Many have been around since right after the Big Bang created the universe nearly 14 billion years ago. And if life on Earth is made of atoms that are from all the way back then... will those atoms keep existing forever? That’s what CrowdScience Listener Rob in Australia would like to know. Lees meer

Caroline Steel investigates the immortality of atoms by travelling to CERN, the world’s largest particle physics laboratory located along the border of France and Switzerland. There, theoretical physicist Matthew McCullough explains whether the smallest atoms can decay or survive the test of time.

Physicist Marco van Leeuwen from Nikhef, the National Particle Physics Laboratory in the Netherlands, gives Caroline a behind-the-scenes tour of the ALICE experiment and the Large Hadron Collider at CERN. She learns how atoms are smashed at incredibly high speeds, and whether that might spell the end of an atom.

And all life on earth is made up of atoms, but how does a collection of tiny particles become a living being? Astrobiologist Betül Kaçar from the University of Wisconsin, Madison, breaks down how life works from an atomic point of view.

Presenter: Caroline Steel

Producer: Imaan Moin

Editor: Ben Motley

(Photo: Hands cupping a glowing atom in the studio - stock photo. Credit: Paper Boat Creative via Getty Images)

Why are some animals black and white?

3 oktober 2025 · 27 min

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Listener Jude in Canada wants to know why some animals are black and white. Why do zebras risk being so stripy? Why do pandas have such distinct marking? And do they have something in common? Lees meer

Presenter Caroline visits Pairi Daiza, a zoo in Belgium. Together with her guide for the day, Johan Vreys, she looks at these weird and wonderful animals up close. First, she visits three zebras having breakfast. Ecologist Martin How from the University of Bristol explains his ingenious experiment involving horses with zebra blankets. Next on the tour is the giant panda which, according to Prof Tim Caro from the University of Bristol, looks at the way it does to camouflage in snowy forests in China. But there are many more animals to see, and many more reasons to be monochrome, including the penguin and its tuxedo-like colouration. Hannah Rowland, senior lecturer at the University of Liverpool explains that it might have more than just a single function. It turns out, scientific answers aren’t always black and white.

Presenter: Caroline Steel
Producer: Florian Bohr
Editor: Ben Motley

(Photo: The zebra was running gracefully running in the green water. Credit: Surasak Suwanmake/Getty Images)

Answers to even more questions

26 september 2025 · 26 min

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Sometimes in science, when you try to answer one question it sparks even more questions. Lees meer

The CrowdScience inbox is a bulging example of that. We get tons of new questions every week and many of those are following up on episodes we’ve made. Sometimes you want us to go deeper into part of the answer, or sometimes a subject intrigues you so much that it inspires further questions about it.

In this episode presenter Caroline Steel is on a mission to answer some of those questions.

The CrowdScience episode How do fish survive in the deep ocean? led listener Ivor to wonder what sort of vision deep sea fish might have. On hand to answer that is Professor Lars Schmitz, Kravis Professor of Integrated Sciences: Biology, at Claremont McKenna College in the USA

Sticking with vision, we also tackle a question inspired by the CrowdScience episode Do we all see the same colour? For years listener Catarina has wondered why her eyes appear to change colour. Professor Pirro Hysi, ophthalmologist at the University of Pittsburgh, sheds some light on that subject.

In India, Rakesh listened to the CrowdScience episode Will the Earth ever lose its moon? and wondered about Jupiter’s many moons. The European Space Agency’s Ines Belgacem is working on a new mission to study Jupiter’s moons. She explains which of the giant planet’s ninety seven moons are ones for Rakesh to watch.

We also hear how the episode Why can’t my dog live as long as me? caught the attention of listener Lisa... and her cat. She had us falling in love with the long history of falling cats and the scientists who study them. Caroline is joined by Professor Greg Gbur, physicist at the University of North Carolina, Charlotte in the USA and author of Falling Felines and Fundamental Physics.

Could this episode of follow up questions lead to an episode investigating the follow up questions to these follow up questions? Have a listen and, who knows, maybe you’ll find yourself inspired to email crowdscience@bbc.co.uk

P…

Do birds understand us?

19 september 2025 · 26 min

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CrowdScience listener David is a bird whisperer. Lees meer

On his family farm in Guinea, he would mimic the call of the black-headed weaver. He could replicate it so well that the birds would fly in close, curious to find out who was calling. David has been wondering if he was actually communicating with the weaver.

In the foothills of the Austrian Alps is a research hotspot with a curious history. It was here that a scientist first began studying birds in their natural environment. That work continues today with Andrew Katsis from the University of Vienna, who knows the local flock of greylag geese by name. His research shows that animals aren’t just anonymous members of a group, they have personalities, relationships, and the ability to recognise one another.

But what else do birds know? Thomas Bugnyar, professor of social behaviour and animal cognition, spends his time trying to get inside the mind of ravens. His work suggests they can understand their surroundings, make rational decisions, and even solve complex problems.

Plus, we meet Ellie, a cockatoo with the ability to use a touchscreen computer to “talk.” She has a working vocabulary of more than 1,500 words. And when she presses a button, it would appear she is not just pecking at random, she is choosing purposefully, responding in ways that suggest birds may not only understand us, but communicate back.

Presenter: Caroline Steel
Producer: Minnie Harrop and Harrison Lewis
Series producer: Ben Motley

(Photo: Close up of Greylag goose with blue background Credit: Harrison Lewis, BBC)

Why am I so sentimental?

12 september 2025 · 26 min

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CrowdScience listener Kerry started thinking about his sentimental attachment to his possessions when he began sorting through an old trunk, full of objects from his past. He wants to know why we get so attached to things that often have no use anymore and why it’s so hard to give them away. Lees meer

Anand Jagatia investigates why the objects we accumulate during our lives mean so much to us.

He talks to psychologists Mary Dozier and Melissa Norberg and finds out that our possessions offer stability and comfort from the earliest age. That keepsake you brought home from your holiday may also stir memories about days gone by - and that’s one reason why we may find it hard to part with the things we own, because they help us to access our emotions. And the items we collect through our lives can come to represent our identity too.

Anand visits the Museum of Broken Relationships in Zagreb, Croatia, where people from all over the world have donated possessions from relationships that ended, whether romantic or family, and discovers that sentimental attachment is universal.

Presenter Anand Jagatia

Producers Jo Glanville and Imaan Moin

Editor Ben Motley

(Photo: Memories box in book shelf - Credit: Jan Hakan Dahlstrom via Getty Images)

Will drinking milk help me live longer?

5 september 2025 · 26 min

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Milk: drink a lot of it and we’ll grow big and tall with strong bones. That’s what many people are told as children, but just how true is this accepted wisdom? CrowdScience listener JJ in Singapore is sceptical. He wants to live a healthy life for as long as possible, and he’s wondering whether drinking cow’s milk will help or hinder him on this mission. Lees meer

All mammals produce milk, and our mother’s milk is our very first drink as babies. So what actually is the white stuff? Mary Fewtrell, professor of paediatric nutrition at UCL, gives presenter Chhavi Sachdev the lowdown on just how fundamental breastmilk is to us all.
But are we meant to continue drinking milk from other animals once we grow up? This behaviour of ours is rare among mammals… so Christina Warinner, professor of evolutionary biology at Harvard University, tells us when in our history cow’s milk entered our diet, and how we even came to be able to digest it.

And is there any truth in the accepted wisdom that cow’s milk will give us stronger bones? Karl Michaelsson, professor of medical epidemiology at Uppsala University, has researched just this – and the answer isn’t what you’d expect. Karl helps Chhavi sift through the complex evidence to see whether milk is actually any good for us.

Presenter: Chhavi Sachdev
Producer: Sophie Ormiston
Editor: Ben Motley

(Photo:Lady milking cow, Nadiad, Gujarat, India)

How long will traces of our civilisation last?

29 augustus 2025 · 34 min

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What will remain of us hundreds of millions of years from now? And how can we be so certain that we are the first technologically advanced species on Earth? Lees meer

These unsettling questions have been haunting listener Steve. If fossils can be lost to deep time through erosion and subduction into the Earth’s mantle, how would anyone — or anything — ever know that we had been here? And if an earlier species had built a civilization that rose and fell, would we even be able to find traces of it?

To investigate, CrowdScience presenter Caroline Steel speaks to the scientists trying to answer these questions, while producer Sam Baker goes fossil hunting on the Jurassic Coast in the UK.

Caroline speaks with astrophysicist Adam Frank at the University of Rochester in the US, who along with NASA scientist Gavin Schmidt developed the Silurian hypothesis – the idea that if an advanced species had existed deep in Earth’s past, they might have vanished without leaving a trace.

But palaeontologists Jan Zalasiewicz and Sarah Gabbott from the University of Leicester in the UK argue that humans are already leaving an indelible mark in the form the chemical and material fingerprints we’re pressing into Earth’s crust. They contend that the ‘technofossils’ we are producing will last a very long time indeed.

Along the way, Caroline and producer Sam discover just how rare fossils really are, how even the tiniest particles of pollution will give us away to far-future explorers, and why car parks might be our ultimate legacy. What they find is at once unsettling and oddly comforting: humanity could be fleeting, but our impact probably won’t be.

Could we really have missed evidence of an ancient civilization? And what strange clues will we leave behind for whoever, or whatever, comes next? We explore Earth’s geological memory to find out.

Presenter: Caroline Steel
Producer: Sam Baker
Editor: Ben Motley

(Photo: Old phone embedded in concrete layer with defocused landscape background Credi…

How does camouflage work?

22 augustus 2025 · 37 min

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Camouflage isn't just for chameleons! Military forces around the world deck their soldiers out in those distinctive green and brown uniforms, to give them the best chance of staying safe, and remaining undetected. But how do they work? Why do they look so different from country to country? And why do you still see soldiers wearing it in the city, when it can't possibly work as camouflage? Lees meer

These are the questions in the mind of Crowdscience listener Paul, in Uganda. In his home of Kampala he often sees soldiers on patrol. As a botanist, he's fascinated by the nature-inspired designs, and he wants to know how they came to be. So Alex Lathbridge sets off to find out.

At Camolab at the University of Bristol, Laszlo Talas talks Alex through the history of battle-dress. There have been some extraordinary designs over the years, some of them quite beautiful in their way, and many with hidden easter eggs printed into the design!

In a patch of forest on the outskirts of Prague, Alex gets to try some of the latest gear out for himself. Fully kitted out in ghillie suit, camouflage chaps, face mask and goggles, he tries to disappear into tue background. With the help of 4M Tactical, the company who manufacture a cloak currently in use in Ukraine. It has the power to make you invisible, not just in the visible spectrum, but in the infrared too. With high tech sensors and infrared cameras now a staple of the modern battlefield, clothes like this are becoming essential.

Not all camouflage technology belongs to the military. Futuristic clothing company Vollebak in London are using 'the fabrics of the future' to design high tech streetwear for savvy 21st century urban warriors. Founder Steve Tindall shows Alex their prototype Thermal Camo Jacket, which uses hundreds of layers of graphene to give the illusion of heat, or cold. Steve says that hiding in plain sight is less about concealing yourself from human eyes, and more about avoiding the pervasive sensors and constant survei…

How long does light last?

15 augustus 2025 · 26 min

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When listener Rob from Devon, UK, heard of a newly detected planet light years away, he was struck by the sheer scale the light must travel to reach us here on Earth. It got him wondering: How long does light last? What is the oldest light we have ever observed? And does light ever die? Lees meer

To find out, presenter Anand Jagatia calls on some of the brightest minds in astronomy and physics.

Astronomer Matthew Middleton from the University of Southampton explains how scientists still struggle to define exactly what light is. What we do know is that light comes in many forms, and choosing the right kind can peel back the cosmic curtain, revealing the universe’s deepest and darkest secrets. That knowledge will prove vital in Anand’s search for the oldest light ever observed.

At the European Southern Observatory in Chile, staff astronomer Pascale Hibon gives Anand a behind-the-scenes look at the Very Large Telescope, one of the most advanced optical instruments on Earth, perfectly placed under some of the clearest skies on the planet. Light from the objects Pascale studies has often travelled for billions of years, making her images snapshots of the distant past.

If light has crossed the vastness of the universe to reach us, it must be unimaginably ancient. But what will become of it in the far future? Could we trap it and preserve it forever? Miles Padgett at the University of Glasgow, has spent his career trying to pin it down. As Anand discovers, physics can be more philosophical than you might expect.

Presenter: Anand Jagatia
Producer: Harrison Lewis
Editor: Ilan Goodman

(Photo: An area of deep space with thousands of galaxies in various shapes and sizes on a black background. Most are circles or ovals, with a few spirals. Credit:G. Östlin, P. G. Perez-Gonzalez, J. Melinder, the Jades collaboration, M. Zamani/ESA/Webb, Nasa and CSA)

Can we stop the rain?

8 augustus 2025 · 32 min

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CrowdScience listener Rit, from Pune in India, is staring out of his window at the falling rain. It’s been pouring for four days now, and shows no sign of stopping. The laundry is piling up, all his shoes are wet, and he’s worried about the effect it’s having on the environment, and on agriculture. When it rains like this, the animals suffer, and the crops are destroyed. Lees meer

Cloud seeding and Weather Engineering are hot topics right now, and can bring the rain to places that need it. But Rit wants to know whether we can artificially stop the pouring rain, especially in an emergency. Following the devastating floods in Texas, it’s clearly not just a problem for countries with a monsoon season.

Presenter Chhavi Sachdev is also sitting in a downpour at home in Mumbai. She dons her rain jacket and rubber boots to try and find out whether science can help Rit with his question. From controlling the clouds in India, to bringing rain to the deserts of the UAE, to firing high-powered lasers into the skies above Geneva, we find out what weather engineering is really capable of.

With thanks to:

Dr Thara Prabhakaran, from the Indian Institute of Tropical Meteorology

Alya Al Mazroui, Director of the UAE Research Program for Rain Enhancement Science

Jean-Pierre Wolf, Applied Physics Department of the University of Geneva

Presenter: Chhavi Sachdev
Producer: Emily Knight
Series Producer: Ben Motley

(Image: Girl carrying umbrella while standing on road against trees during rainfall. Credit: Cavan Images/Getty Images)

How are teeth made?

1 augustus 2025 · 30 min

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CrowdScience listener Jon started wondering how our teeth are created while he was in the dentist’s chair. It took his mind off the drilling. He wants to know how our teeth are made, what goes into them and how come we only get two sets of teeth when other animals, like sharks, grow thousands of new ones throughout their lives. Lees meer

Anand Jagatia goes back to prehistoric times to discover how the story of teeth began millions of years ago. Palaeontologist Yara Haridy explains that teeth weren’t designed originally for eating at all, but as a kind of armour on the exoskeletons of fish that was also sensitive to the environment. It turns out that our teeth in fact are part of our evolutionary success story. Biological anthropologist Peter Ungar reveals that we flourished as a species because our teeth are designed to get the maximum energy from our food.

Anand discovers how teeth can even be grown in a lab when he meets researchers Ana Angelova Volponi and Xuechen Zhang whose team has managed to replicate the environment in which teeth develop. He also talks to Katsu Takahashi who has discovered a method for developing a third set of teeth. It’s a whole new way of creating teeth that will change the way we make them.

Presenter Anand Jagatia
Producer Jo Glanville
Editor Ben Motley
Studio Manager Bob Nettles
Production co-ordinator Ishmael Soriano
Translation, Katsu Takahashi interview Bethan Jones

Trailer: 13 Minutes Presents: The Space Shuttle

28 juli 2025 · 3 min

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The epic space story of a sci-fi dream that changed spaceflight forever. Told by the Nasa astronauts and team who made it happen. Our multi-award-winning podcast is back, hosted by space scientist Maggie Aderin-Pocock. She tells the story of triumph and tragedy - of a dream that revolutionised modern space travel forever. Lees meer

You can listen to the trailer here. To hear episodes, search for 13 Minutes Presents: The Space Shuttle, wherever you get your BBC podcasts.

13 Minutes Presents: The Space Shuttle is a BBC Audio Science Unit production for the BBC World Service.

Theme music by Hans Zimmer and Christian Lundberg, and produced by Russell Emanuel, for Bleeding Fingers Music.

Archive:
Mission audio and oral histories, Nasa History Office.

Could technology improve our brains?

25 juli 2025 · 26 min

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What comes to mind when you imagine the future of humanity? Could a computer make your mind more efficient? Enhance your cognition? Or cure a disorder you've been grappling with all your life? CrowdScience listener Mariana from Mexico hopes that one day technology will be able to help improve our brains. Lees meer

Presenter Alex Lathbridge seeks out some of these brain boosters, exploring emerging technologies in deep brain stimulation at City St George’s University of London in the UK. Professor Francesca Morgante and Dr Lucia Ricciard explain how they’re using technology to treat Parkinson’s.

And could brain technology help with even the most enigmatic elements of our minds? Dr Robert Hampson at Wake Forest University in the USA takes us through his research in restoring memory impairment.

Along the way we interrogate the ethical implications of the breakneck speed of progress in brain augmentation research with researcher Anders Sandberg from the Institute of Future Studies in Sweden.

Presenter: Alex Lathbridge
Producer: Emily Bird
Series Producer: Ben Motley

What if the Earth spun backwards?

18 juli 2025 · 26 min

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Your whole life is governed by spin. The rotation of our planet tells you when to wake up, and Earth’s orbit around the Sun is the reason why some of us dig out a jumper for half the year and a t-shirt for the rest. But what if that all changed? Lees meer

That’s exactly what 8-year-old Geronimo in Ecuador wants to know. He and his dad, Fabian, have got themselves dizzy trying to figure out what would happen if the Earth stopped spinning, or better yet, started spinning in the opposite direction. Would everyone fly off into space? Would school be at night? Eager for answers, they decided to ask CrowdScience.

Presenter Anand Jagatia embarks on an interstellar journey, blasting off with the celestial origins of spin itself. Astronomer Amy Bonsor from the University of Cambridge in the UK explains how Earth’s rotation began, with collapsing clouds of gas, planetary pile-ups and crushing gravitational force.

At Keele Observatory, things get apocalyptic. Anand meets astronomer Jacco van Loon, who explains what would happen if Geronimo somehow waved a magic wand and brought Earth’s rotation to a halt. With months of unbroken daylight or darkness, devastating storms and even the loss of the Earth’s magnetic shield, it’s like the script of a disaster movie.

Wave that magic wand again and we imagine a world where the Earth not only stops... but starts spinning the other way. Meteorologist Joao Basso from the University of Leipzig in Germany walks us through a mind-bending 2018 study that tells us the surprising things that would happen to the global climate.

Presenter: Anand Jagatia
Producer: Harrison Lewis
Series Producer: Ben Motley

Where did Earth’s water come from?

11 juli 2025 · 31 min

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Here's a conundrum that has captivated scientists: when Earth formed 4.5 billion years ago, our planet was essentially a ball of molten rock. Any water that might have been present during the planet's formation would surely have boiled away immediately. Yet today, water covers about 70% of Earth's surface. Lees meer

So where did all this water come from? And more intriguingly, when did it arrive? Listener Bill in the USA wants to know, and Presenter Caroline Steel is after answers.

Assistant Professor Muhammad Abdul Latif is an early earth physicist at United Arab Emirates University. He explains how his modelling has helped us to understand when water first appeared in our universe.

The early earth was not a water-friendly place - a hellscape of molten rock, volcanic eruptions and constant bombardments from comets and asteroids, with high levels of solar radiation. These conditions would have evaporated the water. And according to Professor Richard Greenwood at Open University, our earth’s molten iron core would have been a ball of rust if there had been water in the proto-earth mix.

So if the water hasn’t always been here, where did it come from?

At the Natural History Museum in London, Professor Sara Russell has been comparing the isotopic "fingerprint" of Earth's water with water found in the asteroid Bennu, captured and brought back by the recent Osiris Rex NASA mission. It’s a good match for earth’s water, but could it really be the answer to our question?

Presenter: Caroline Steel
Producer: Marnie Chesterton
Editor: Ben Motley

(Image: Man overlooking the sea from cliff top. Credit: Gary Yeowell via Getty Images)

Can we harness solar energy from other stars?

4 juli 2025 · 26 min

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Listener Dickson Mukisa from Uganda has been gazing up at the stars. But he’s not making wishes. He wants to know whether we can harness their energy, in the same way we do with our OWN star – the sun. After all, they may seem small and twinkly to us, but each one is a gigantic flaming ball of energy, with a power outputs averaging around 40 quadrillion kilowatt-hours per year – EACH! With somewhere between 100 and 400 BILLION stars in our own galaxy alone, that’s a lot of power! Can we get ‘solar power’ from stars that are such a long way away from earth? And what might we use it for? Lees meer

Alex Lathbridge heads to the University College London Observatory, to peer through the eyepiece of an enormous telescope and see some stars for himself. Professor Steve Fossey explains just how much of the light energy of the stars reaches us on earth. In other words, how BRIGHT they are.

Once the starlight reaches earth of course, we have to capture it. Could traditional solar panels do the job? Alex meets Professor Henry Snaith from the University of Oxford, to find out about the future of photovoltaic technology, and why it could all be heading out to space.

Once in space, things start getting weird! What if we made an enormous fleet of solar panels, and put them all into orbit around a star, soaking up every last drop of that precious energy? That might sound like science fiction, but the idea has been around for decades. It’s called a Dyson Sphere, or Dyson Swarm. Swedish researcher at the Insitute for Future Studies, Anders Sandberg explains how we might be able to build one around a neighbouring star... in around 10,000 years or so.

But maybe it’s not all about light. Finally, Alex explores the mysterious, invisible energy of the ‘solar wind’, with Pekka Janhunen, Finnish physicist and inventor of the “E-Sail”, which might be able to harness the power of the stellar wind, too.

Presenter: Alex Lathbridge
Producer: Emily Knight
Series Producer: Ben Motley

(Image: Astronom…

Why are twins special?

27 juni 2025 · 26 min

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No one really cares that CrowdScience listener Sam has a younger brother, but they do care about his sister. In fact, they’re fascinated by her. That’s because Sam and his sister are fraternal twins. Lees meer

He’s been wondering all his life why he’s treated differently. Could it be cultural? Twins have long appeared in classical mythology, revered literature, and playful comedies—captivating artists and audiences alike across time and continents. Or is there something more scientific behind our fascination? Why are twins special?

Anand Jagatia investigates with Karen Dillon from Blackburn College in the USA, who says it’s more complicated. Over the years we have created stereotypes of who and what twins are. Our perception has been warped by history and pop culture. As an identical twin herself, she knows firsthand how stereotypes can shape a twin’s identity.

Philosopher Helena De Bres from Wellesley College in the USA believes these stereotypes play on human anxieties. Their similarities and differences are derived from their biology, maybe our genes have more of an influence over our personalities and behaviours than we like to think?

And Nancy Segal agrees, Director of the Twin Studies Centre at California State University in the USA. She has spent her career studying twins. She’s found that nearly every trait, whether it be behavioural or physiological, has a genetic component to it.

Anand is sure to leave you thinking that Sam, his sister and all the other twins across the globe, really are special!

Presenter: Anand Jagatia
Producer: Harrison Lewis
Series Editor: Ben Motley

(Image: Twin girls (8-10) wearing matching coats and pigtails. Credit: Jade Albert Studio, Inc via Getty Images)

How can we persuade more people to cycle?

20 juni 2025 · 26 min

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Cycling is good for our health, good for the planet, and it can be an efficient way of moving around busy cities. But despite all the rational arguments for it, in most cities the number of people who get on their bikes is low. Lees meer

CrowdScience listener Hans wants to know whether it’s time to change our tactics. Could we persuade more people to cycle if we moved away from focusing on well-intentioned rational arguments and use messages that appeal to our desires and vanity instead? What does the science say? Presenter Caroline Steel is on the case.

She meets Winnie Sambu from World Bicycle Relief to learn about why people in countries like Kenya to choose the bike to get around. She heads out on a ride with psychologist Professor Ian Walker from the University of Swansea to find out what barriers there might be to persuading people to cycle.

She also takes a lesson from one of the world’s top cycling nations as she talks to Marie Kåstrup, a cycling campaigns expert who has advised the Danish government on inspiring cycling and sustaining it in the city of Copenhagen. Also in Denmark, Caroline meets behavioural scientist Dr Pelle Guldborg Hansen who shares his experience in the art of persuasion.

Presenter: Caroline Steel
Producer: Tom Bonnett
Series Producer: Ben Motley

Was there an idyllic time before carnivores?

13 juni 2025 · 26 min

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Was there ever a time when life on earth was peaceful? Free of violence? No predators, no prey, just... vibes? Or has nature always been 'Red in Tooth and Claw'? Lees meer

Have we always been eating each other?

Our listener Scott sent us on a quest to discover the origins of predators and prey, and to find out what all this ‘eat or be eaten’ stuff is really about.

Taking us back to the very dawn of life on earth, Professor Susannah Porter from the University of Santa Barbara lets Alex peer into an extraordinary world of microscopic warfare. It’s a dog-eat-dog (or, microbe-dissolve-microbe) world, with single celled organisms doing battle with each other. For billions of years, this was life on earth! Tiny, violent, and completely fascinating.

But what about bigger creatures? More complex ones - animals? Speeding forward several billion years, Alex arrives in the Ediacaran Period – a time of unusual tranquility, where strange, plant-like animals lived in relative peace. At the Natural History Museum in Oxford, UK, palaeontologist Dr Frankie Dunn shows him around.

So where did real predators come from, then? Alex is joined by Dr Imran Rahman as he ushers in one of the most extraordinary periods in Earth’s history – the magnificently named Cambrian Explosion! Here we find real predators, with teeth, claws, and impressive hunting appendages. Through the fossil record, we can see an arms race developing – as predators get more sophisticated, so does their prey. It’s ON.

Finally, Alex wonders if our own evolution, shaped as it has been by this predator-prey arms race, might have been very different without the threat of being chomped. Professor Lynne Isbell from the University of California, Davis takes Alex on a trip into our primate past, and tackles one of our most fearsome predators: snakes.

Presenter: Alex Lathbridge
Producer: Emily Knight
Series Producer: Ben Motley

What’s that background hum I hear?

6 juni 2025 · 28 min

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In the dead of night at his home in Machinjiri, Malawi, CrowdScience listener John can hear a small, but persistent, hum. Whenever it’s quiet enough, the hum is there – but what’s causing it? And is John the only one who can hear it? Lees meer

Reports of consistent, low-pitched noise have been popping up around the world for decades. No one knows this better than Dr Glen MacPherson, who runs the World Hum Map. He tells presenter Caroline Steel his theory for what’s behind these hums.

And Caroline does some investigating of her own. We visit the Isle of Lewis off the coast of Scotland, where residents are reporting a hum. We hear about the impact that persistent noise has on people’s lives, and find out… can Caroline hear the hum too?

We also ask why some people can hear a hum but others can’t. We head to an anechoic chamber – one of the quietest places in the world – to speak to Professor Jordan Cheer, who puts Caroline’s low-frequency hearing to the test.

From industrial activity to internally generated sounds, we sift through the noise to try and find out what could be causing listener John’s hum.

Presenter: Caroline Steel
Producer: Sophie Ormiston
Series Producer: Ben Motley

What on earth is quantum?

30 mei 2025 · 30 min

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Listener Christine wants to understand one of the strangest phenomena in the universe. But to get to grips with it, she’ll need a crash course in the bizarre behaviour of the very small. Here, things don’t act the way you might expect — and it’s famously hard to wrap your head around. Lees meer

Anand Jagatia has assembled some of the sharpest minds in the field and locked them in a studio. No one’s getting out until Christine and Anand know exactly what’s going on. Or at least, that’s the plan.

On hand to help are Kanta Dihal, lecturer in science communication at Imperial College London; James Millen, King’s Quantum Director at King’s College London; and particle physicist Harry Cliff from the University of Cambridge.

Prepare to enter the world of the very small—and the very weird—where particles can be in two places at once, influence each other across vast distances, and seem to decide what they are only when observed. Hear how these once-theoretical oddities are now driving a technological revolution, transforming everything from computing to communication.

Presenter: Anand Jagatia
Producer: Harrison Lewis
Series Producer: Ben Motley

Can eating honey help save bees?

23 mei 2025 · 27 min

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CrowdScience listener Saoirse is vegan and doesn’t eat honey. But she’s been wondering - might honey actually have environmental benefits, by giving bee populations a boost? Lees meer

To find out, presenter Anand Jagatia dons a bee suit and opens up some hives with biologist Dave Goulson, who reveals that there are over 20,000 bee species on earth – and not all of them need saving. Honeybee researcher Alison Mcafee talks about the importance of beekeeping for crop pollination, and why honeybee colonies around the world are collapsing. Although, as she explains, in some places beekeeping might actually be bad for endangered wild bees. We travel to Kenya to meet Loise Njeru and Lucy King, who show how the humble honeybee can be a powerful tool for conservation – helping to protect the mighty elephant. And, on a rooftop in London, former beekeeper Alison Benjamin explains how we can support the wild bee species that need our help.

Producer and presenter: Anand Jagatia
Location recording: Sophie Ormiston
Series Producer: Ben Motley
Production Co-ordinator: Ishmael Soriano

Is my yoghurt really alive?

16 mei 2025 · 26 min

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Bulgaria is famous for its yoghurt, a fermented milk food full of ‘good’ bacteria that has kept hungry Bulgarians healthy for over 4000 years. Lees meer

Inspired by that, and a question from a CrowdScience listener in California USA, Marnie Chesterton and Caroline Steel are immersing themselves in Bulgarian culture with a programme about Bulgarian cultures, recorded at the 2025 Sofia Science Festival.

So, are the ‘live’ cultures in fermented foods actually alive by the time you eat them, and how can you tell? If you can eat the mould in blue cheese, can you eat the mould on cheese that isn’t supposed to be mouldy? Is traditional food really better for you? And if you put a drop of vanilla into a litre of milk, how come it all tastes of vanilla?

Marnie and Caroline are joined by a chemist who was a member of Sofia University’s ‘Rapid Explosion Force’, a food technologist with a PhD in sponge cakes and a Professor of molecular biology who says that we contain so much bacteria that we’re only 10% human.

With questions on food from around the world and from the audience in Sofia, Marnie and Caroline will be digesting the answers, as well as some local delicacies.

Presenter: Marnie Chesterton & Caroline Steel
Producer: Emily Knight
Series Producer: Ben Motley

Is red sky at night really sailor’s delight?

9 mei 2025 · 28 min

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You may have grown up hearing the saying “red sky at night, sailor’s delight, red sky in morning, sailor’s warning” - or maybe a variation of it. CrowdScience listener Alison, who sees many dazzling red skies from her home in the Yukon, Canada, certainly did. And now she wonders if the saying is a sensible prediction of coming weather or just another old wives’ tale. Lees meer

Alison and presenter Anand Jagatia run a little experiment, getting up at the crack of dawn and staying up until dusk for 5 days to record if the sunset and sunrise can predict their local weather.

While we wait for the results, we track this weather proverb back to its ancient roots to find out how important it may have been to the people without satellites or even thermometers to guide them.

We also tap into the expertise of modern-day weather predictors, meteorologists. What are the atmospheric pressure systems that cause red skies, and how do they influence the weather globally? And what exceptions to the rules might turn a trusty old proverb on its head?

Presenter: Anand Jagatia
Producer: Ella Hubber
Series Producer: Ben Motley

Why can't I fall asleep?

2 mei 2025 · 29 min

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Some people fall asleep almost as soon as their head touches the pillow, while for others it can take hours of tossing and turning. CrowdScience listener Assia needs at least 45 minutes to get to sleep: it's always taken her a long time to drift off no matter how tired she is, and nothing seems to make a difference. She asked us to investigate. Lees meer

Presenter Caroline Steel turns to experts to find out what happens in our bodies when we fall asleep, and why it’s more difficult for some than others. Eus van Someren explains how our bodies know when it’s time to get some rest and what can influence the difficulty of getting to sleep from our earliest years. Morten Kringelbach reveals that there may be more stages of sleep than we thought, and Ada Eban-Rothschild tells us why we have something to learn from the birds and the bees about getting a good night’s rest.

Caroline has trouble getting to sleep herself, and volunteers to have her sleep monitored in Cardiff University’s sleep lab. And we share some expert tips on falling asleep more easily.

Presenter: Caroline Steel
Producer: Jo Glanville
Editor: Cathy Edwards
Studio Manager: Jackie Margerum
Production co-ordinators: Jana Holesworth and Josie Hardy

With thanks to Professor Milton Mermikides for permission to include his composition ‘Transitions’.

(Photo: Caroline Steel takes a nap in Cardiff University’s sleep lab)

Can we feed everyone?

25 april 2025 · 31 min

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According to the United Nations Food and Agriculture Organisation, 800 million people are going to bed hungry every night, but 2 billion people in the world are malnourished. Farmers across the globe produce enough food to feed 10 billion people, yet there are only 7.6 billion of us. Lees meer

We know there is enough food to go around, but filling tummies is only the start – we also need a varied diet. CrowdScience visits Nairobi during GGIAR Science Week, a hub for agricultural scientists. They are meeting to discuss the changes needed to get the right crops into the soil and the right food on the plates of those who need it.

Presenters Anand Jagatia and Alex Lathbridge are joined by a live audience and a panel of experts Lindiwe Sibanda, Sieglinde Snapp and Alex Awiti. Together they explore questions from our listeners in Kenya and around the world: whether we can restore natural habitats whilst promoting food security; why human waste isn’t used more commonly as a fertiliser; and what impact empowering women in agriculture will have on our ability to feed the world.

Recorded at CGIAR Science Week at the UN headquarters in Nairobi.

Image: Drone view of tractor ploughing a field
Image Credit: Justin Paget via Getty Images

Presenters: Anand Jagatia & Alex Lathbridge
Producer: Harrison Lewis
Editors: Martin Smith & Cathy Edwards
Production Co-ordinators: Ishmael Soriano & Josie Hardy
Studio Managers: Gayl Gordon, Andrew Garratt & Sarah Hockley

Why am I always late?

18 april 2025 · 26 min

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CrowdScience listener Sid is running late, and he’s turning to science to find an excuse. He and his partner Steffi in Singapore have very different attitudes to timekeeping. They wonder if this is down to their different cultural upbringings, or if they just had very different brains to start with. Lees meer

Presenter Chhavi Sachdev puts her own time perception skills to the test to try to understand how subjective our sense of time can be. And we discover how the language we grow up speaking can influence the way we think about punctuality.

Presenter: Chhavi Sachdev
Producer: Emily Bird
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Jackie Margerum

Why do animals swallow rocks?

11 april 2025 · 30 min

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What would you discover inside the stomach of a sea lion? CrowdScience listener Robyn found out first-hand when she volunteered at her local museum in Adelaide, Australia. The team dissecting the specimen removed around 30 rocks from the animal’s stomach, and Robyn wants the Crowdscience team to find out how and why they got there. Lees meer

Presenter Anand Jagatia uncovers a whole world of rock-munching creatures, from ostriches to ichthyosaurs. In search of answers we investigate Canadian sea lion research, and rummage through the vaults at the Natural History Museum in Bamberg, Germany.

Presented by Anand Jagatia
Produced by Emily Bird

Image: Australian Sea Lion (Neophoca cinerea), Hopkins Island, South Australia
Credit: Stephen Frink via Getty Images

How do you measure a mountain?

4 april 2025 · 26 min

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On the banks of the St Lawrence River in Quebec stands a 100-year-old lighthouse. While initially built to help boats navigate one of Canada’s most difficult waterways, the Point-de-Père site now also holds a different responsibility: it is a key reference for measuring sea levels around the entire North America continent. Lees meer

But this is all set to change. With the development of new satellite technology, the tricky task of measuring sea levels is being updated - which could mean mountains around North America get brand new official heights.

In this episode we revisit a question from CrowdScience listener Beth, who wondered about the elevation signs she saw scattered along a mountainous road, indicating how high above sea level she was. As sea levels rise, will all the elevation signs need repainting? And how do you measure sea level, anyway?

The height of an enormous pile of rock like Ben Nevis, or Mount Everest feels unchangeable. But we measure them relative to the nearest patch of sea, which is where our story becomes complicated. Unlike water in a bath, sea level is not equal around the world. In fact, nothing on earth - not the sea, the shore or the mountains - is stable or constant, so the question of what you measure from and to becomes incredibly tricky. But that hasn’t stopped scientists risking life and fingers to use an ever-evolving array of technologies to find answers.

Join host Marnie Chesterton as she dives into the mechanics of the latest sea level technology, and how it could make a big difference to understanding our unpredictable world.

Presenter: Marnie Chesterton
Producer: Julia Ravey and Marnie Chesterton
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano and Jana Holesworth
Studio Manager: Emma Harth

(Image: Elevation Sign Post, Rocky Mountain National Park. Credit: Stephanie Beverungen via Getty Images.)

Where in the world will I weigh least?

28 maart 2025 · 26 min

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Host Anand Jagatia tackles gravity - a fundamental force of the universe yet also an everyday mystery that has baffled several listeners. Can you outrun it? Or at least use it to get fitter? If it varies, does that mean that you weigh less, depending on where on earth you stand? And if it’s the force of attraction between any objects with mass, are you technically more attractive after eating a massive cake? Lees meer

Professor Claudia de Rham from Imperial College London explains the basics of gravity, while we discover the best place on earth to weight ourselves, with Professor Paddy Regan from Surrey University and NPL Fellow in Nuclear and Radiation Science and Metrology.

Anand takes a very fast spin on a special chair to experience extra gravity, thanks to Professor Floris Wuyts from the University of Antwerp, Kings College London and Minister of Science of Asgardia.

And finally, we talk to an expert lined up at the other end of a hypothetical hole through the earth: Professor Richard Easther from the University of Auckland, New Zealand. What would happen if we fell straight through the earth?

CrowdScience finds gravity a force to be reckoned with.

Presenter: Anand Jagatia
Producer: Marnie Chesterton
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano and Jana Bennett-Holesworth
Studio Manager: Jackie Margerum and Duncan Hannant

Photo: Anand Jagatia experiencing extra g-force

Are there global food allergy hotspots?

21 maart 2025 · 30 min

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Are food allergies higher in the West than the East? UK-based listener Jude wants to know the answer. Her daughter-in-law Min didn’t know anyone with food allergies when she was growing up in South Korea and thinks that they’re not so common there. Lees meer

Host Alex Lathbridge investigates. Along the way, he finds out what makes us sensitive to food allergies and how much that depends on our environment. He volunteers to have an allergy test, learns what triggers food allergies and tries to discover what lies behind their increase around the world.

Alex talks to some of the leading experts on food allergies in search for an answer to our listener’s question: Paul Turner breaks down what happens in our bodies when we have an allergic reaction; Jennifer Koplin explains why Australia tops the league table for food allergies and Michael Levin reveals what he found out in his ground-breaking research in South Africa comparing urban and rural populations. We also hear from Hana Ayoob, who grew up in Singapore and the UK, who describes what it’s like to suffer from multiple food allergies and describes the difference in cultural attitudes. Finally, we turn to Sooyoung Lee in South Korea to see if our listeners are right about the difference in rates for food allergies between East and West.

Presenter: Alex Lathbridge
Producer: Jo Glanville
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Duncan Hannant

(Image: Young Asian father with cute little daughter grocery shopping for dairy products in supermarket Credit: d3sign via Getty Images)

Are humans naturally monogamous?

14 maart 2025 · 27 min

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CrowdScience listener Alina is in a relationship with a polyamorous partner and is very happy with this arrangement, which got her thinking – why is monogamy so often the norm in human societies? Lees meer

Presenter Caroline Steel goes on an anthropological odyssey to figure out where this drive to find a single partner - and stick with them - comes from.

What can science tell us about how human relationships developed, and whether having one or many partners is more 'natural'?

Evolutionary biologist Kit Opie of the University of Bristol joins us at London Zoo to help us understand the mating systems of our closest primate relatives.

To find out how polygamy developed in some parts of the world we speak to anthropologist Katie Starkweather of the University of Illinois Chicago.

And we learn about the chemistry of bonding from Sarah Blumenthal at Emory University, who explains how the brains of prairie voles may give us clue about the neurochemicals which shape human relationships.

Presenter: Caroline Steel
Producers: Priya Sippy, Ben Motley and Imaan Moin
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Steve Greenwood

(Image: Dancing wedding cake figurines Credit: Peter Dazeley via Getty Images)

Is water wet?

7 maart 2025 · 26 min

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The wetness of water seems blindingly obvious - but dive into the science and things aren’t so clear. Lees meer

CrowdScience listeners Rachel and Callum were washing their hands one day and it got them thinking about wetness. Why does water feel the way it does? And what makes a liquid wet?

To find out, presenter Anand Jagatia takes a closer look at the behaviour of liquids with materials scientist Mark Miodownik, and finds out why they might not be as wet as we think.

We learn what’s really behind the sensation of feeling something wet on your skin, with the help of physiologist Davide Filingeri and PhD student Jade Ward.

And we turn to a philosopher, Vanessa Seifert, and a chemist, Tim Neudecker, to puzzle out exactly how many water molecules you need before the property of wetness emerges.

Presenter: Anand Jagatia
Producer: Anand Jagatia
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Bob Nettles and Andrew Garratt

(Image: A photo of a droplet falling into a body of water Credit: Flaviu Cernea / 500pxvia Getty Images)

Whatever happened to tangerines?

28 februari 2025 · 29 min

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It’s citrus season in the northern hemisphere, and fruit trees are bursting with oranges and lemons. But CrowdScience listener Jonathan wants to know what happened to the tangerines he ate as a child in the 1960s? He remembers a fruit that was juicy, sweet and full of pips, found each Christmas at the bottom of his stocking. Tangerines today, he thinks, just don't compare. Lees meer

Crowdscience tries to track down this elusive fruit. Presenter Anand Jagatia traces the tangerine's origins back to Ancient China, as botanist David Mabberley explains that the name ‘tangerine’ comes from a fruit that made its way from Asia, to Africa and the Moroccan port of Tangier, before arriving in the US in the early 1800s. Professor Tracy Kahn from UC Riverside tells us about the hybridisation process that goes into breeding modern tangerines, but says that while the season for these fruits has been dramatically extended, there’s a cost in terms of diversity and flavour.

Who better to help us track down this missing mandarin than a fruit detective? Well, that’s one of pomologist David Karp’s other job titles, and he reveals exactly which cultivar we might be looking for: the Dancy. So where can we find one? Over on Friend’s Ranches in Ojai, California, Emily Ayala shows us two trees planted by her late grandfather, and explains that nothing grown since really matches its unique flavour.

So what will listener Jonathan think when we send him a box?

Presenter: Anand Jagatia
Producer: Marijke Peters
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Jackie Margerum

(Image: Citrus oranges grow on tree, Hong Kong Credit: CHUNYIP WONG via Getty Images)

Why isn't the sky green?

21 februari 2025 · 27 min

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Vermillion red, vibrant orange, golden yellows, even violet – we're enchanted by the colours that make up a stunning sunset or sunrise. CrowdScience listener Paulina, a lighting designer from Chile, often uses the sunsets she sees from her balcony as inspiration for her designs. And during the day and night, the sky can be all sorts of shades of blue. But Paulina wonders why, in the colour palette of the sky, she never sees any green. Lees meer

CrowdScience gazes skywards to investigate. Presenter Caroline Steel travels to the Arctic Circle to meet atmospheric physicist Katie Herlingshaw. Katie explains why we usually see the sky as blue, and what makes it transform into fiery reds and oranges at sunrise and sunset. We also peer into the science of perception, as neuroscientist Bevil Conway tells us what’s going on in our eyes (and brains) to make the colours we see in the sky.

But there are some rare occasions when the sky can appear to be green, such as in a rainbow or a green flash at sunset. And then there is the spellbinding green glow of the aurora - the Northern and Southern Lights. We visit the northernmost aurora observatory in the world to try to understand this phenomenon. Are green skies more common than we think?

Presenter: Caroline Steel
Producer: Hannah Fisher
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Sarah Hockley

(Photo: View of sunset in Santiago, Chile. Photo montage courtesy of Paulina Villalobos)

Is anything truly random?

14 februari 2025 · 26 min

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CrowdScience listener Dorit has a problem. She wants the tiles in her new bathroom to be arranged randomly but, no matter what she does, it still looks like they form some kind of pattern. Lees meer

This has got Dorit thinking about randomness – what is it, how do you create it, why do we find it so hard to recognise, and is anything really random at all? And if nothing is truly random, does it mean that everything is theoretically predictable? Tiling your bathroom is a much more existential problem than you might have thought.

Never afraid of a question, whether big (is everything pre-determined?) or small (how do I tile my bathroom?), CrowdScience is on the case.

Anand Jagatia heads to Switzerland to meet Hugo Duminil-Copin, a mathematician at the University of Geneva who specialises in probability theory. On the top floor of an old bank, Hugo has Anand flipping an imaginary coin in a random order. Hugo explains that randomness is something that cannot be predicted by any means – so why is it so easy for Hugo to guess what Anand’s next move is?

Meanwhile, at the National Institutes of Mental Health in Maryland USA, Susan Wardle is a cognitive neuroscientist who researches how the human brain processes visual information. Can neuroscience help Dorit with her tiling problem, and is there a reason why the human brain likes to put random objects into some kind of order?

Geneva is also the birthplace of the first Quantum Random Number Generator for smartphones, and CrowdScience has persuaded some of the University of Geneva’s finest quantum physicists to hook a photon detector up to a synthesiser. Thanks to Tiff Brydges and Nicolas Brunner, we can actually hear quantum particles behaving randomly. But is quantum randomness truly random, or just a pattern that we can’t see? And could quantum physics help Dorit tile her bathroom?

Presenter: Anand Jagatia
Producer: Ben Motley
Editor: Cathy Edwards
Production co-ordinator: Ishmael Soriano
Technical producer: Jackie Margerum

Why can't I remember my early childhood?

7 februari 2025 · 27 min

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Some of our biggest achievements happen in the first years of our lives. Taking our first steps, picking up a complex language from scratch, and forming relationships with some of the most important people we’ll ever meet. But when we try to remember this period of great change, we often draw a blank. Lees meer

After losing his Dad aged four, CrowdScience listener Colin has grappled with this. Why can’t he recall memories of such a monumental figure in his life, yet superficial relationships from his teens remain crystal clear in his mind? Colin takes presenter Marnie Chesterton to visit some of the significant locations of his childhood, places he would have spent many hours with his late father; and he recounts his earliest memories.

On this trip down memory lane, Marnie discovers the psychological reason behind our lack of early childhood memories comes down to a phenomenon known as infantile amnesia. Tomás Ryan, neuroscientist at Trinity College Dublin, discusses some of the theories behind this universal experience, and Sarah Power from the Max Planck Institute for Human Development discusses her groundbreaking study exploring this form of forgetting in real time. Elaine Reese from the University of Otago digs into how our environment and culture can influence the age of our earliest memories, and why some of the first things we remember might not be the big, huge events you’d expect. And we hear about fascinating new insights from animal studies that hint these memories could still be lurking inside our heads...

Presenter: Marnie Chesterton
Producer: Julia Ravey
Content Editor: Cathy Edwards
Production Co-ordinators: Ishmael Soriano & Josie Hardy
Technical producer: Emma Harth

(Photo: Marnie Chesterton and CrowdScience listener, Colin, on the swings in Belfast.)

Is my smartwatch good for my health?

31 januari 2025 · 28 min

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Smartwatches are increasingly popular and many of us use these wearable devices to monitor our performance and improve our fitness. But how reliable is the data they collect, and can they actually make us healthier? Lees meer

CrowdScience listener Caitlin from Malawi is a big fan of her smartwatch. Her husband Fayaz, however, is much more sceptical of its accuracy, and has asked us to investigate. We meet up with them both at the gym, where Caitlin and presenter Caroline Steel put their fitness trackers – and themselves – to the test.

We visit public health researchers Dr Cailbhe Doherty and Rory Lambe, who investigate the accuracy of wearable consumer devices, at University College Dublin. Caroline again pushes herself to the limit to see how her smartwatch results measure up to those from gold standard laboratory equipment.

But is it crucial for smartwatches to be accurate? If they get us off the couch, is that what makes the difference to our health? Health behaviour expert Dr Ty Ferguson from the University of South Australia has studied this very question. And finally, how does quantifying our every move affect the way we think about ourselves and how we live? Professor Deborah Lupton from UNSW Sydney, shares some insights.

Presenter: Caroline Steel
Producers: Jo Glanville and Sophie Ormiston
Editor: Cathy Edwards
Technical producer: Sarah Hockley
Production co-ordinator: Ishmael Soriano

How high can birds fly?

24 januari 2025 · 27 min

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While watching a feisty cockatoo chase after a hawk, CrowdScience listener Alison saw the hawk catch a thermal and rise effortlessly into the sky. The cockatoo gave chase, but the hawk climbed higher and higher until it became just a tiny speck, barely visible to the naked eye. Lees meer

And that got Alison thinking: just how high can birds go? Are there altitude limits for our feathered friends? Could a cockatoo, a sparrow, or even a duck reach such dizzying heights if they really put their wings to it?

Presenter Alex Lathbridge sets out to investigate. Biologist Catherine Ivy reveals that life above the clouds isn’t easy. At high altitudes, the air is thinner, oxygen is scarce, and wings don’t generate as much lift. But some bird species have evolved incredible adaptations to overcome these challenges.

Among them: bar-headed geese, renowned for their daring flights over the world’s tallest mountains. Physiologist Lucy Hawkes delves into how these geese defy the odds with their remarkable physiology, revealing the surprising discoveries she made while putting some of them on a treadmill.

From super-powered hearts to clever lungs, we uncover the secrets behind nature’s impressive aviators.

Presenter: Alex Lathbridge
Producers: Ilan Goodman and Jeremy Grange
Editor: Cathy Edwards
Production co-ordinator: Ishmael Soriano
Technical producer: Sarah Hockley

(Image: OIE A TETE BARREE (Anser indicus) EN VOL Credit: Jean-Patrick DEYA / Contributor via Getty Images)

Which animal has the biggest carbon footprint?

17 januari 2025 · 29 min

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Carbon footprints are a measure of how much we each contribute to the greenhouse gases that warm the Earth’s atmosphere. The global average of carbon dioxide emissions is nearly 5 tonnes per person per year, although it can be triple that in certain countries. Lees meer

But one CrowdScience listener in Ghana is wondering about the bigger picture. After all, humans aren’t the only species on this planet. So which other animal has the biggest carbon footprint?

CrowdScience presenters Caroline Steel and Marnie Chesterton are on the case, examining and arguing over the animal that deserves the top spot for this title.

Caroline, a vegan, points to the cow as the top contender, since the livestock sector produces 14.5% of total greenhouse gas emissions, and cows, whether as meat or dairy animals, are responsible for the majority of that. The team look at initiatives around the world to be more efficient with each animal out there. But maybe it’s time to put another sector in the spotlight? Pets. We love our dogs and cats but do their meat-based diets win them a place on the podium?

From most loved to most detested, we look at the role that key pests play in upsetting the carbon budget. Could a small beetle with a large appetite for greenery be an unusual winner, thanks to the trees these pests destroy over their lifetimes?

Is the biggest offender a carbon footprint, hoofprint, pawprint, or clawprint?

Presenters: Caroline Steel and Marnie Chesterton
Producer: Marnie Chesterton
Editor: Cathy Edwards
Production co-ordinator: Ishmael Soriano
Technical producers: Sarah Hockley and Donald MacDonald

Is beer better without alcohol?

10 januari 2025 · 33 min

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In the past stout beer has been touted for its supposed health benefits. Is there any truth to those claims - and what happens if you take the alcohol out? Lees meer

CrowdScience listener Aengus pondered these questions down at the pub, after noticing most of his friends were drinking non-alcoholic beers. He wondered how the non-alcoholic stuff is made – what’s taken out and what’s added in – and whether the final product is better for you than the alcoholic version.

It’s a question that takes us to Belgium, home to the experimental brewery of a global drinks company which takes the growing market for alcohol-free beer very seriously. David De Schutter, head of research and development, shows host Marnie Chesterton how to take alcohol out of beer without spoiling the flavour.

We also find our way to a yeast lab in Leuven, Belgium where Kevin Verstrepen and his team have found another way to make alcohol-free beer with the help of industrious microbes: yeast varieties that brew beer without producing any alcohol in the first place. And how do they compare to the alcoholic versions? We discuss the importance of aromas in our perception of beer’s taste.

So should listener Aengus stick to non-alcoholic stout? We speak to scientist Tim Stockwell about the health drawbacks of alcohol, even in moderation. And gut microbiome researcher Cláudia Marques fills us in on her delicious pilot study, which looked at the effects of both non-alcoholic and alcoholic beers on our digestive tract.

Along the way, Marnie taste-tests what's on the market, and asks the experts why this particular grocery shelf has become so much bigger and more flavourful in recent years.

Presenter: Marnie Chesterton
Producer: Sam Baker
Editor: Cathy Edwards
Production co-ordinator: Ishmael Soriano
Technical producers: Giles Aspen, Andrew Garratt and Donald MacDonald

(Image: Close-up of waitress holding craft beer at bar, Brazil Credit: FG Trade via Getty Images)

Why am I embarrassed when I fall?

3 januari 2025 · 26 min

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When listener Diana fell on a run on her birthday, her first instinct was not to check her bruised hand, but instead to get up as quickly as possible and act as if nothing had happened. She felt embarrassed. Meanwhile, her son Marley loves to watch fail videos that, mostly, show people falling over. So why does falling – something that can cause serious injury – elicit both embarrassment and laughter? Lees meer

In the name of CrowdScience, presenter Caroline Steel trips, stumbles and falls. She spends a morning with clown Sean Kempton who teaches her slapstick skills, including how to do it safely.

Psychologist Rowland Miller explains why falling can be embarrassing and shares his theory of why humans have developed this emotion in the first place. Then it’s time for Caroline to try out Diana’s predicament herself. If a BBC presenter falls in a park, will she feel embarrassed?

From embarrassment to laughter, psychologist Janet Gibson lists the ingredients of a funny fall, and humour expert Caleb Warren explains how they can get funnier with distance. Then Caroline tries, semi-successfully, to make members of the public laugh. Will clown Sean do a better job?

Presenter: Caroline Steel
Producer: Florian Bohr
Editor: Cathy Edwards
Production coordinators: Ishmael Soriano
Sound engineers: Bob Nettles, Tim Heffer and Giles Aspen

I didn’t know that!

27 december 2024 · 26 min

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Did you know that flies fly in rectangles, fish hide by lighting themselves up and the moon is lifting the ground underneath your feet? Anand Jagatia quizzes members of the CrowdScience team on the moments from the past year that had them scratching their heads in amazement. Lees meer

We hear Dr Erica McAlister’s attempts to calculate how many flies have ever existed, and about flies’ mating choreography, courtesy of Prof Jochen Zeil. We learn how to tell a mosquito’s sex thanks to Eggrey Aisha Kambewa and Dr Steve Gowelo.

Astronomer Dr Darren Baskill describes tides not of water but of land; Dr Edie Widder paints a vivid picture of a camouflaged creature of the deep; and we explore starfishes’ five-fold symmetry with Dr Imran Rahman.

Khimlal Gautam, Mountaineer and Chief Survey Officer for the Government of Nepal, tells us of the near-death experience he had when checking the height of Mount Everest.

And finally, axolotl expert Dr Elly Tanaka is astonished at the dedication of CrowdScience presenter Alex Lathbridge to the subject of her research.

Presenter: Anand Jagatia
Producer: Ben Motley
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Managers: Donald MacDonald and Giles Aspen

(Photo: Lost in formulas Credit: Cimmerian via Getty Images)

Will the Earth ever lose its Moon?

20 december 2024 · 26 min

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The Moon has always sparked human curiosity. It governs the tides and biological rhythms. It’s inspired myths and stories. It’s inspired us to reach out and explore it. And it's certainly inspired CrowdScience listeners, who have sent us a host of questions about it. And in a special lunar-themed episode we’ve brought together a panel of astronomers and planetary scientists to help answer them. Lees meer

What would life be like if there was no Moon? Would there even be life? Or what if we had two moons? Are the Moon and Earth equally battered by meteors? What would happen if an asteroid collided with the Moon? And could the Moon ever escape Earth’s gravity?

Anand Jagatia is joined by Prof Sara Russell, Head of the Planetary Materials Group at the Natural History Museum in London; Prof Neil Comins from the University of Maine, author of the book What if the Moon didn’t Exist?; and Prof Katarina Miljkovic from Curtin University in Perth, Australia.

Presenter: Anand Jagatia
Producer: Jeremy Grange
Editor: Cathy Edwards
Production Co-ordinator: Ishmael Soriano
Studio Manager: Andrew Garratt

(Photo: Landscape with the rising of the full moon during the golden hour Credit: Jose A. Bernat Bacete via Getty Images)

Why does pain sometimes feel good?

13 december 2024 · 29 min

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It seems bizarre to seek out experiences that are uncomfortable or downright painful. Yet examples abound: it’s common to eat painfully hot chillies, drink bitter coffee, or ‘feel the burn' when exercising - and enjoy it. Lees meer

CrowdScience listener Sandy is baffled by this seemingly counterintuitive phenomenon, and has asked us to investigate. Presenter Anand Jagatia turns guinea pig as he tests a variety of unpleasant sensations, and unpicks the reasons we’re sometimes attracted to them.

He meets chilli-eating champion Shahina Waseem, who puts Anand’s own attraction to spicy food to the test. Food scientist John Hayes explains how our taste receptors work and why our genes affect the appeal of bitter food. Neuroscientist Soo Ahn Lee describes her research looking at what happens in participants’ brains when they eat chocolate and capsaicin, the chemical that makes chillies hot.

As for the ‘pleasurable pain’ we sometimes experience when exercising, sports doctor Robin Chatterjee reveals the secrets of the ‘runner’s high’, while neuroscientist Siri Leknes explains why the feeling that something’s good for us can make discomfort pleasurable.

Presenter: Anand Jagatia
Producer: Jo Glanville
Editor: Cathy Edwards
Production co-ordinator: Ishmael Soriano
Sound engineer: Sue Maillot

(Image: Young man have bath in ice covered lake in nature and looking up, Czech Republic Credit: CharlieChesvick via Getty Images)