CrowdScience

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’s the oldest light we’ve ever observed? And does light ever die? 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 describes himself as “a kid in a sweet shop” when it comes to physics, and that enthusiasm comes in handy, because 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. In a sense, she’s pretty much a time traveller. 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? “If we knew what light is, that might be an easier question to answer,” says Miles Padgett at the University of Glasgow, who has spent his career trying to pin it down. As Anand discovers, physics can be more philosophical than you might expect. From redshifted galaxies at the edge of the observable universe to exotic materials that can slow light to walking pace, CrowdScience explores whether we can catch light, how it changes over time, and why truly understanding it remains one of physics’ most stubborn challenges. Presenter: Anand Jagatia Producer: Harrison Lewis Editor: Ilan Goodman (Image: 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. More distant galaxies are smaller, down to being mere dots, while closer galaxies are larger and some appear to be glowing. Red and orange galaxies contain more dust or more stellar activity Credit:ESA/Webb, NASA & CSA, G. Östlin, P. G. Perez-Gonzalez, J. Melinder, the JADES Collaboration, M. Zamani (ESA/Webb))

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. 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 via Getty Images)

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. 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

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. 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.

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. 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

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? 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

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. 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)

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? 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: Astronomer looking at the starry skies with a telescope. Credit: m-gucci via Getty Images)

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. 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)

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. 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 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'? 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

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? 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

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. 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

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? 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

Bulgaria is famous for its yoghurt, a fermented milk food full of ‘good’ bacteria that has kept hungry Bulgarians healthy for over 4000 years. 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: Anand Jagatia Producer: Ella Hubber Series Producer: Ben Motley

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. 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

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. 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)

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. 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

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. 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

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. 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