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CrowdScience

BBC World Servicewww.bbc.co.uk

We take your questions about life, Earth and the universe to researchers hunting for answers at the frontiers of knowledge.

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Episodes

Are atoms immortal?

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. 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 Sw...

Oct 10, 202526 min

Why are some animals black and white?

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? 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...

Oct 03, 202527 min

Answers to even more questions

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

Sep 26, 202526 min

Do birds understand us?

CrowdScience listener David is a bird whisperer. 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 to...

Sep 19, 202526 min

Why am I so sentimental?

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. 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 ...

Sep 12, 202526 min

Will drinking milk help me live longer?

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. 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, professo...

Sep 05, 202526 min

How long will traces of our civilisation last?

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? 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 inves...

Aug 29, 202534 min

How does camouflage work?

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? These are the questions in the mind of Crowdscience listener Paul, in Uganda. In his home of Kampala he ofte...

Aug 22, 202537 min

How long does light last?

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? 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...

Aug 15, 202526 min

Can we stop the rain?

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 t...

Aug 08, 202532 min

How are teeth made?

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 desig...

Aug 01, 202530 min

Trailer: 13 Minutes Presents: The Space Shuttle

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 Shut...

Jul 28, 20253 min

Could technology improve our brains?

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 Francesc...

Jul 25, 202526 min

What if the Earth spun backwards?

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 eve...

Jul 18, 202526 min

Where did Earth’s water come from?

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 Muh...

Jul 11, 202531 min

Can we harness solar energy from other stars?

CrowdScience investigates if humanity can harness energy from stars beyond our Sun. The episode reveals the immense disparity in brightness between the Sun and distant stars, making terrestrial energy harvesting impractical. It explores advancements in photovoltaic technology, including multi-junction and perovskite cells, before venturing into hypothetical Dyson Spheres for vast stellar energy collection and the innovative E-Sail, which could harness solar and interstellar wind for propulsion in the far future.

Jul 04, 202526 min

Why are twins special?

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 fascinat...

Jun 27, 202526 min

How can we persuade more people to cycle?

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 sci...

Jun 20, 202526 min

Was there an idyllic time before carnivores?

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 extraor...

Jun 13, 202526 min

What’s that background hum I hear?

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 som...

Jun 06, 202528 min

What on earth is quantum?

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...

May 30, 202530 min

Can eating honey help save bees?

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 ar...

May 23, 202527 min

Is my yoghurt really alive?

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 t...

May 16, 202526 min

Is red sky at night really sailor’s delight?

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 t...

May 09, 202528 min

Why can't I fall asleep?

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. E...

May 02, 202529 min

Can we feed everyone?

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 meeti...

Apr 25, 202531 min

Why am I always late?

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 influen...

Apr 18, 202526 min

Why do animals swallow rocks?

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 resea...

Apr 11, 202530 min

How do you measure a mountain?

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. 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 N...

Apr 04, 202526 min

Where in the world will I weigh least?

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? Professor Claudia de Rham from Imperial College London explains the basics of gravity, w...

Mar 28, 202526 min
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