

CrowdScience
BBC World Service
We take your questions about life, Earth and the universe to researchers hunting for answers at the frontiers of knowledge.
Episodes
Mentioned books

Oct 17, 2025 • 26min
Can we record our senses?
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? 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)

Oct 10, 2025 • 26min
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 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)

Oct 3, 2025 • 27min
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 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)

Sep 26, 2025 • 26min
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 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 Presenter: Caroline Steel Producer: Tom Bonnett Editor: Ben Motley(Photo: Innovation and new ideas lightbulb concept with Question Mark - stock photo Credit: Olemedia via Getty Images)

Sep 19, 2025 • 26min
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 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)

Sep 12, 2025 • 26min
Why am I so sentimental?
A listener grapples with nostalgic attachments to possessions, sparking an exploration into why we hold on to sentimental items. Experts discuss how memories tied to objects provide comfort and stability. The emotional struggle of letting go reveals the deep connections we have to our identities through items. A visit to the Museum of Broken Relationships demonstrates how universal these feelings are, showcasing artifacts that tell poignant stories of love and loss. The podcast sheds light on our complex emotional bonds with the objects we cherish.

Sep 5, 2025 • 26min
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, 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)

Aug 29, 2025 • 34min
How long will traces of our civilisation last?
Join Professor Sarah Gabbott from the University of Leicester, a leading paleontologist and co-author of 'Discarded,' as she explores the lasting legacy of human civilization. She discusses how 'technofossils'—the enduring marks we leave behind—will be detectable for millions of years. The conversation dives into the Silurian Hypothesis, pondering whether earlier advanced species left any trace at all. Plus, listeners discover the rare art of fossil hunting on the Jurassic Coast and how our everyday pollution uniquely shapes Earth's future geological record.

11 snips
Aug 22, 2025 • 37min
How does camouflage work?
Dive into the intriguing world of camouflage, from its origins in nature to military applications. Discover how patterns and colors evolved through historical context and reflect national identity. Learn about the latest advancements, like a cloak that renders soldiers invisible, and explore thermal camouflage technology's innovative capabilities. Personal accounts shed light on the need for adaptability in modern warfare, highlighting the ongoing arms race between concealment and detection in an ever-evolving battlefield.

12 snips
Aug 15, 2025 • 26min
How long does light last?
Pascale Hibon, a staff astronomer at the European Southern Observatory in Chile, shares her expertise in studying distant celestial objects using the Very Large Telescope. The conversation reveals how light from these objects often journeys for billions of years, making Hibon a kind of time traveler. They discuss the nature of light, its dual wave-particle characteristics, and breakthroughs in telescope technology. The podcast also raises intriguing questions about the longevity of photons and their transformative journey across the universe.