Unexpected Elements

BBC World Service
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Oct 2, 2026 • 50min

Rogue Agents

This week’s news of an AI agent managing to hack into an Australian government website has the Unexpected Elements team exploring the sneaky science of infiltration.Marnie Chesterton is joined by science journalists Paul Adepoju and Andrada Fiscutean to discover how South African drongo birds have developed an ingenious technique to protect their nest from cuckoo eggs, and to hear about the unusual approach being developed to help get eyedrops past the body’s immune system so they can reach the retina.We’re also joined by Dr Bart Geert, Professor of Atmospheric Science at the University of Wyoming in the US, to explore the science of how to manipulate clouds to try to help produce more rain in drought-ridden areas.We also find out about how the tracking data that comes from tagging wild dogs in Zambia could help to ensure better approaches to their conservation in the future. We hear about your cases of pareidolia, and learn why aging leads to men going bald but also growing longer hair on other parts of the body. All that and more in this week’s Unexpected Elements. Presenter: Marnie Chesterton Producer: Dan Welsh with Alice Lipscombe-Southwell, Imy Harper and Robbie Wojciechowski
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Sep 25, 2026 • 50min

An identity crisis

When a NATO fighter jet was sent to investigate what appeared to be a suspicious drone near Vilnius airport, the culprit turned out to be something rather less threatening: a flock of birds. Inspired by this case of mistaken identity, the Unexpected Elements team explores the science of getting things wrong. We discover why our brains are so eager to spot faces in everyday objects, from clouds to power sockets, and hear how this tendency may have evolved as a shortcut for detecting friends and foes. We also investigate the widespread issue of mislabelled cell lines that have found their way into thousands of scientific studies, raising questions about research reliability and reproducibility. Then we meet Alex Donovan from the MRC Laboratory of Molecular Biology at Cambridge University, who tells us the story of brain organoids, or "mini-brains", a field of research born from an apparent laboratory mistake that has gone on to transform neuroscience. Elsewhere, we hear how a WhatsApp message helped identify a devastating banana disease outbreak in Tanzania, ask whether anybody else in the world has exactly the same face as you, and explore how the venom of the Gila monster ended up inspiring drugs now used by millions of people around the world. All that plus more unexpected elements.Presenter: Marnie Chesterton Producer: Ella Hubber with Alice Lipscombe-Southwell and Robbie Wojciechowski
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Sep 18, 2026 • 50min

A distorted view

With the United Nations encouraging wider use of the Equal Earth map, a projection designed to better represent the true size of Earth's landmasses, the Unexpected Elements team have been thinking about distortion and the surprising new ways we can see the world and beyond. We discover that every city's subway system has its own unique microbial fingerprint, so distinctive that researchers can identify a location from a simple swab. Then we meet the black-capped chickadee, a tiny bird whose remarkable memory-map helps it keep track of thousands of hidden food stores.Astrophysicist Miguel Zumalacárregui joins us to explain gravitational lensing, the phenomenon that bends and distorts light as it travels through the Universe. We hear how these cosmic distortions help astronomers study distant galaxies, dark matter and even black holes.We also learn why Europe's mountain summits are becoming greener while still losing rare plants, ask why many continents seem to point downwards, and explore the story behind the online maps in our pockets.All that, plus many more Unexpected Elements.Presenter: Marnie Chesterton, with Andrada Fiscutean and Paul Adepoju Producers: Alice Lipscombe Southwell, with Ella Hubber and Debbie Kilbride
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Sep 11, 2026 • 50min

The phizz-whizzing science of Roald Dahl

Roald Dahl Day is celebrated each year on 13 September. Dahl gave us much-loved children’s books like Matilda, The BFG and Charlie and the Chocolate Factory, which have captivated kids for generations.Dahl is also a controversial figure, and made anti-semitic remarks that his family have since apologised for. We explore the separation of art and artist, and go looking for the science hidden in Dahl’s fantastical stories.We find out about the scientists brewing up chocolate – not in a factory, but in a laboratory. And remember how the BFG sent ‘golden dreams’ into kids’ bedrooms? We hear how anaesthetists are ensuring that patients enjoy good dreams while sedated. And remember Bruce Bogtrotter, the much-loved side character in Matilda who famously scoffed a gigantic chocolate cake? Inspired by his story, we decided to chew over the science behind eating competitions with Professor James Smoliga from Tufts University School of Medicine.Presenter: Marnie Chesterton, Tristan Ahtone and Sandy Ong Producer: Alice Lipscombe-Southwell, Sophie Ormiston and Debbie Kilbride
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Sep 4, 2026 • 50min

The show must go on

The 80th birthday celebrations of the late, great Queen frontman Freddie Mercury have us marvelling at mercury at an elemental level: as a killer, a cure and more.First, we hear about how to make a telescope mirror out of a spinning bowl of liquid mercury. Then we hear about killer queens; it’s a gruesome tale of pheromone-induced ant warfare.Next, Freddie’s rare condition that caused him to have four extra incisors in his upper jaw leads us to discuss the secrets hidden within our teeth. We’re joined by archaeologist Carolyn Freiwald from the University of Mississippi, whose work on the teeth of ancient people tells us much about both their lives and our own.Also, the secret to getting rid of earworms, ancient civilisations hidden beneath the Amazon, and why you should never mess with dimethyl mercury.Presenter: Marnie Chesterton, Kai Kupferschmidt and Camilla Mota Producer: Lucy Davies, Alice Lipscombe-Southwell, Imy Harper and Debbie Kilbride
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Aug 28, 2026 • 50min

A very dry episode

Vast swathes of Europe and Asia are experiencing drought conditions, thanks to relentless heatwaves and lack of rain. This week, we find out why drought conditions could unexpectedly lead to an increase in water-borne disease. Next up, we take a trip to Lake Malawi to discover why a tiny fly could help us rewrite the science of insects. Also on the show, we’re joined by Professor Dan Parsons from Loughborough University in the UK, who tells us about the rivers that lurk beneath the sea. Elsewhere, we hear about the tech that could help reduce textile waste, we find out why rehydrating raisins won’t turn them back into grapes, and discover how to suck water from thin air. All that, plus many more Unexpected Elements. Presenter: Marnie Chesterton, with Chhavi Sachdev and Phillys Mwatee Producers: Alice Lipscombe-Southwell, with Debbie Kilbride and Imy Harper
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Aug 21, 2026 • 50min

Fashionably late

News of an Australian library book finally finding its way home 150 years after it was borrowed has the Unexpected Elements team thinking about things that get forgotten, filed away or simply turn up much later than expected.We start with the story of a meteorite from Mars that spent millions of years travelling through space before ending up in a university drawer. Then, we investigate why scientists believe California may be centuries overdue for a massive earthquake known as "The Big One".Next, Martin Woodward from GitHub joins us to explain how millions of lines of computer code are being preserved deep beneath the Arctic in a vault designed to protect humanity's digital knowledge for generations to come.Plus, we hear about the penguin vaccinators working to protect Australian wildlife from bird flu, discover if smells, tastes and touch can be measured, and explore the dying art of reading a book. All that, plus many more, unexpected elements.Presenter: Marnie Chesterton Producers: Lucy Davies, Ella Hubber, Imy Harper and Robbie Wojciechowski
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Aug 14, 2026 • 50min

Light entertainment

As Europe experiences its first total solar eclipse in almost 30 years this week, Unexpected Elements investigates the surprising science that emerges when sunlight is blocked out. We travel to the forests of Italy, where we investigate whether trees can communicate their eclipse plans to each other. We learn about an ambitious scientific plan to launch a wall of bubbles the size of Brazil into outer space. And we contemplate whether astronauts will ever need to take rice cookers the moon. Also on the show, Anneliese Hodge, a doctoral researcher from the University of Plymouth in the UK joins us to help us learn more about how sunscreen - while good for us humans - can be destructive to marine life. Elsewhere in the programme, we hear about the newly arrived crows bothering the people of Nairobi, Kenya, and discuss another pesky problem: people not wearing headphones on public transport. All that plus more unexpected elements. Presenter: Alex Lathbridge Producers: Dan Welsh, Lucy Davies and Robbie Wojciechowski
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Aug 7, 2026 • 50min

Someone's always watching

The UK's Royal Society for the Protection of Birds has found that birdwatching is the second-fastest growing hobby amongst Gen Z with 750,000 of them regularly venturing into the outdoors to spot some of our feathered friends. Inspired by this new appreciation for an old pastime, the Unexpected Elements team are on the lookout for some birdwatching science. First, we watch birds, but did you know they watch us back? We hear how crows don't just hold grudges; they also pass on those grudges to their peers. Then, from birds watching us to birds watching for us. We learn all about the patterns of vulture crime scene detectives. Inspired by the citizen science nature of bird watching we talk to Professor Brooke Simmons about Galaxy Zoo, a website where people can volunteer to sort through images of galaxies and perhaps stumble on some mysterious green blobs. We also bring you the newest evidence of ice age-old bird appreciation, explore BALLS or the ambitious pan-African experiment to send spherical radio antennae to the moon, and ask does music distract or help you concentrate? The answer might depend on your social skills. All that plus more unexpected elements. Presenter: Marnie ChestertonProducers: Ella Hubber, Lucy Davies and Robbie Wojciechowski
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Jul 31, 2026 • 50min

Down The Rabbit Hole

Dr. Franziska Kohlt, historian of science at King’s College London, links Victorian scientific change to Lewis Carroll’s Alice. She traces Darwinian and industrial influences on the book. Short segments cover shrinking shrews, Alice in Wonderland syndrome, optics and the Cheshire Cat, international translations, and why scientists keep returning to Alice as a tool for exploring bold ideas.

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