CrowdScience

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: Marnie Chesterton & Caroline Steel Producer: Emily Knight 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

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 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.)

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, 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 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.

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)

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?

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)

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

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)

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.

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)

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.

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)

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.

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

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.

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.)

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?

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

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.

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)

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.

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

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?

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)

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?

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

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.

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)

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.

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)

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. 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)

For their fans, jigsaw puzzles are a satisfying challenge, a focus, a chance to put everything else aside for a moment and be creative. But for other people they’re a frustrating jumble of random shapes and colours, a pointless task which is best left in the box. CrowdScience listener Heather is definitely a fan. She loves doing jigsaw puzzles and she wants to know why some people are so good at them. What skills do you need to find a pattern amongst all those shapes and colours? How do our brains, eyes and hands assemble the fragments into the finished article? And why do we enjoy doing them anyway? Presenter Alex Lathbridge puts together the pieces to answer Heather’s question. He sits down to work on a jigsaw with Sarah Mills, the ten-times UK jigsaw puzzling champion (yes... competitive jigsaw puzzling really is a thing!) As he watches Sarah complete the puzzle at lightning speed he gets a few of her top tips. So what’s going on in our brains when we’re doing a jigsaw puzzle? How do we recognise and process colour and shape? Prof Mark Mattson from Johns Hopkins University in the USA has the answer. And it’s all to do with a little seahorse-shaped part of the brain called the hippocampus.

Alex also explores the effect of jigsaws on our brains with neuropsychologist Dr Patrick Fissler. He’s carried out research to investigate the benefits of jigsaw puzzles on our brains as we grow older.

Both listener Heather and ten-times-champion Sarah seem to be better at jigsaws than Alex is. So, based on that sample size of three, women are superior puzzlers compared to men! But has anybody actually cast the net wider to see if that’s really the case? Alex talks to Daniela Aguilar from the University of Lethbridge in Canada about her study to investigate exactly that – and she reveals the results. Heather’s also wondering if any other species enjoy puzzles. And it seems they do! Alex meets Dr Cody McCoy from the University of Chicago to find out about the optimistic, tool-using crows of New Caledonia. From crows to competitive puzzlers, it seems we all relish a challenge!

Presenter: Alex Lathbridge Producer: Jeremy Grange Editor: Cathy Edwards Studio Manager: Bob Nettles Production Co-ordinator: Ishmael Soriano

Do you find your bearings quickly or are you easily disorientated? Do your friends trust you with the directions in a new city?

Finding our way in the physical world, whether that is around a building or a city, is an important everyday capability, one that has been integral to human survival. This week CrowdScience listener David wants to know whether some people are ‘naturally’ better at navigating, so presenter Marnie Chesterton sets her compass and journeys into the human brain.

Accompanied by psychologists and neuroscientists Marnie learns how humans perceive their environment, recall routes and orientate themselves in unfamiliar spaces. We ask are some navigational strategies better than others?

Professor Hugo Spiers from UCL shares his latest lab for researching navigation and tells us that the country you live in might be a good predictor of your navigation skills.

But is our navigational ability down to biology or experience, and can we improve it?

With much of our modern map use being delegated to smartphones, Marnie explores, with Prof Veronique Bohbot what an over-reliance on GPS technology might do to our brain health.

Presenter: Marnie Chesterton Producer: Melanie Brown

(Photo: Man standing on rural road holding up a road map, head obscured by map. Credit: Noel Hendrickson/Getty Images)

As we enter our teenage years, many of us feel like life is just getting started. But for dogs, celebrating a ‘teen’ birthday is a sign of old age, entering a phase when things start slowing down. Listener Susan was besotted with her beloved corgi Copper John and wants to know why our furry companions rarely live as long as us. We investigate what accounts for the huge differences in lifespans across animal species. From fish that live a few weeks, to sharks who can survive for 500 years, what are the factors that affect the ticking on our biological clocks? Central to this field is the idea of ‘live fast, die young’, with some animals burning more quickly through their ‘life fuel’. But is this rate set in stone?

Presenter Anand Jagatia find out how animals’ growth, reproduction and anti-ageing methods contribute to the length of their survival. Dr Kevin Healy, a macroecologist at the University of Galway, discusses some of these theories, explaining how the dangers and luxuries faced by animals during their evolution shape their speed of life.

One example of extreme slow living is the Greenland Shark. John Fleng Steffensen, Professor of Marine Biology at the University of Copenhagen, describes how he helped figure out how old they really are, and how their cold living quarters increase their lifespan. Alessandro Cellerino, physiologist at the Scuola Normale Superiore in Pisa, finds the key to the sharks’ longevity in their DNA.

Anand also goes on a hunt on the west coast of Ireland for a creature that lives fast but surprisingly, dies old. Noel Fahy, research student at the University of Galway, is his guide, while Dr Nicole Foley, Associate Research Scientist at Texas A&M University, reveals the life-extending secrets of this creature.

And geneticist Trey Ideker, Professor at the University of California San Diego, busts the myth that one dog year is seven human years. But how much is this misconception off by?

Presenter: Anand Jagatia Producer: Julia Ravey Content Editor: Cathy Edwards Studio Manager: Sarah Hockley Production Coordinator: Ishmael Soriano

(Photo: Copper John the Welsh Pembrokeshire Corgi, by listener Susan)

Maybe you have a deep, booming voice. Or perhaps it’s light and mellifluous. Some people’s voices are honey-smooth while others are as rough as gravel. But why does your voice sound the way it does? CrowdScience listener Hannah in Berlin is training as a teacher and will be using her voice a lot in the classroom in future. She wants to understand more about it: how can she improve the quality of her voice and protect it? And what factors - physical, genetic and environmental - determine the sound of your voice in the first place?

Together with presenter Marnie Chesterton, Hannah pays a visit to speech tutor Prof Viola Schmidt at the Ernst Busch University for the Performing Arts in Berlin. Viola and actor Aurelius give us a masterclass in just what your voice can do, as they throw words and sounds to each other across the rehearsal room at a dizzying pace. And Viola gives Hannah a few top tips on using her voice clearly and authentically in the classroom.

Hannah’s isn’t the only voice-related question in this episode. Peter from the Kingdom of Eswatini thinks people there speak more loudly than in other countries, and wonders why. To answer Peter’s question we turn to Prof Caleb Everett from the University of Miami. The jury’s out on whether people in some countries really do turn up the volume, but Caleb shares evidence of a link between the climate of a particular region and the sound of its native language. And finally, listener Jonathan has an unusual question for Marnie. When listening to CrowdScience, he can’t tell whether he’s hearing Marnie or fellow presenter Caroline Steel. This got him wondering whether it’s common for two people to sound very similar. Marnie gives Caroline a call, and together they set out to discover if your voice really is unique to you. Caroline tracks down a forensic speech scientist - Dr Jess Wormald from the University of York in the UK – while Marnie speaks to Dr Melanie Weirich from the Friedrich Schiller University of Jena in Germany. And both experts agree that Jonathan may be onto something!

Presenter: Marnie Chesterton with Caroline Steel Producer: Jeremy Grange Editor: Cathy Edwards Production co-ordinator: Ishmael Soriano Studio Manager: Donald MacDonald

CrowdScience listeners David and Tatiana have long been captivated by an unusual dinner table discussion: the peculiar change they’ve noticed over the past 16 years in the sunlight streaming through their bedroom window in Ostend, Belgium. They’re convinced that the room has not only become sunnier but that the actual angle of sunlight has shifted.

Intrigued by their observations, we head to Ostend. Our mission: to investigate three of their theories, enlisting expert help along the way.

Theory 1 – A celestial anomaly? René Oudmaijer at the Royal Observatory of Belgium considers whether our shifting position in the solar system might explain the change.

Theory 2 – Movement in the Earth’s crust? Alejandra Tovar from the Geological Survey of Belgium examines tectonic data to see if the Earth’s crust is moving enough to alter the angle of sunlight.

Theory 3 – Subsidence? Structural engineer Kath Hannigan helps us inspect the building for signs that it may be sinking or twisting.

And we explore one final theory of our own, enlisting memory expert Julia Shaw to examine whether it could all be a trick of the mind. Will the team crack the case?

Presenter: Caroline Steel Producer: Harrison Lewis Editor: Cathy Edwards Production co-ordinator: Ishmael Soriano Studio Manager: Sarah Hockley

(Photo: CrowdScience listeners David and Tatiana standing in front of a window in their house)

Fungi are a mysterious and understudied life form. And to add to the intrigue, some of them actually glow in the dark. This phenomenon has sparked CrowdScience listener Derek's curiosity, and he's asked us to investigate.

Presenter Caroline Steel gets on the case. This is just one example of the natural wonder that is bioluminescence – living organisms that glow. How do they produce their light, and is there any reason for it? Caroline visits a bioluminescent bay in Puerto Rico, and Dr Brenda Soler-Figueroa explains what makes it sparkle.

But it turns out there are many different explanations for why living things glow. Fungi, which listener Derek is particularly interested in, are neither plants nor animals, but an entirely different kingdom of life that we know much less about. Professor Katie Field takes on the task of trying to grow us some bioluminescent mushrooms, while Prof Cassius Stevani explains how – and importantly, why – they glow.

And finally – could we ever harness the power of bioluminescence to our advantage in the future?

Presenter: Caroline Steel Producer: Hannah Fisher Editor: Cathy Edwards Production co-ordinator: Ishmael Soriano Studio Manager: Neva Missirian

(Photo: Omphalotus nidiformis, or ghost fungus, Penrose, NSW, Australia Credit: Louise Docker Sydney Australia via Getty Images)

Can learning new languages make us forget our mother tongue? CrowdScience listener Nakombe in Cameroon is concerned that his first language, Balue, is slipping from his grasp. He has learned multiple languages through his life, but Balue is the language of his family and home. It’s central to his identity and sense of belonging. So why does it seem to be fading from him, and what can he do to get it back?

We search for answers, investigating what happens in our brains when we struggle to recall languages, as well as the social and economic factors that lead to language loss. Presenter Anand Jagatia asks Michael Anderson from the University of Cambridge, an expert on memory and forgetting, whether forgotten languages disappear from our brain, or just become difficult to access. Linguist Monika Schmid from the University of York takes us through the phenomenon of first language attrition, and has words of reassurance and advice for Nakombe and others in his situation.

And we meet Larry Kimura from the University of Hawai’i at Hilo, a pioneer of Hawaiian language revitalization, and Gabriela Pérez Báez, an expert in indigenous languages and language revitalization at the University of Oregon. They explain why languages around the world become threatened, and how to keep them alive.

Presenter: Anand Jagatia Producer: Margaret Sessa Hawkins Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Managers: Sarah Hockley and Omera Ahamed

(Photo: Diccionario, Argentina Credit: PonyWang via Getty Images)

While there is a myriad of deodorants, shower gels and perfumes helping us stay fresh and fragrant today, that hasn’t always been the case. How did humans stay clean in the past, or did they not care so much? And is there an evolutionary reason for human body odour in the first place?

These are questions that CrowdScience listener Sarah has pondered on trips in her camper van, when she wants to keep clean, but washing isn’t always convenient.

In search of answers, presenter Anand Jagatia delves into the sweaty details: where body odour comes from, why some people's armpits don't smell, and whether this heady stink serves any purpose. Could our natural odour really help to attract a partner, or is it just a smelly bacterial by-product?

Anand explores the intriguing mystery of human pheromones, and hears how for hundreds of years, Europeans were terrified of washing.

Contributors: Dr Madalyn Nguyen, Dermatologist Dr Kara Hoover, Biological Anthropologist, University of Alaska Fairbanks Katherine Ashenburg, author, The Dirt on Clean: An Unsanitized History Dr Tristram Wyatt, Department of Biology, University of Oxford

Presenter: Anand Jagatia Producer: Sophie Eastaugh Production co-ordinator: Ishmael Soriano Editor: Cathy Edwards Sound engineer: Emma Harth

(Photo: Girl sweating smelly armpit, Taiwan Credit: PonyWang via Getty Images)

2024 is the biggest election year in history. From Taiwan to India, the USA to Ghana, by the end of the year almost half of the world’s population will have had the chance to choose who governs them. But there are a huge number of possible voting systems – and listener James wants CrowdScience to find out which is the fairest. To do so, we create a fictional country called CrowdLand to try out different electoral systems. Presenter Caroline Steel consults mathematician David McCune and political scientists Eric Linhart and Simon Hix, and we hear from listeners around the world about how they vote in their respective countries. Can we find the perfect voting system for CrowdLand? Contributors: Prof David McCune, William Jewell College, USA Prof Eric Linhart, University of Technology Chemnitz, Germany Prof Simon Hix, European University Institute, Italy Actors: Charlotte Bloomsbury Ross Virgo Presenter: Caroline Steel Producer: Florian Bohr Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Donald MacDonald

(Image: Hand of a person casting a vote into the ballot box during elections, Thailand Credit: boonchai wedmakawand via Getty Images)

With huge heads on top of spindly stalks, how do sunflowers defy gravity to stay standing? That was a question sent to CrowdScience by listener Frank, whose curiosity was piqued by the towering sunflowers on his neighbour’s deck. They stay up not only when the weather is fine, but, even more impressively, during strong winds. Could this feat of strength, flexibility and balance inspire the construction of tall buildings?

It's a question that takes presenter Anand Jagatia to a sunflower festival in England, to see how the sunflower’s long evolutionary lineage has honed its structure. And from tall flowers to tall buildings, we turn to structural engineers, asking how these concepts factor into the design of the world’s tallest skyscrapers. Can ideas drawn from sunflowers or other natural structures help buildings withstand wind, or even storm surges?

Contributors: Stuart Beare, partner and grower at Tulley’s Farm Roland Ennos, Visiting Professor in Biological Studies, University of Hull Sigrid Adriaenssen, Professor of Civil and Environmental Engineering, Princeton University Koichi Takada, founder of Koichi Takada Architects

Presenter: Anand Jagatia Producer: Tom Bonnett Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Bob Nettles

(Image: Tall Sunflower blooming in a field, Melbourne, Victoria, Australia Credit: Naomi Rahim via Getty Images)

The Moon and Earth are drifting gradually further apart. Every year the gap between them increases by a few centimetres. We know that the Moon’s gravity has an important effect on Earth - from controlling the tides to affecting the planet’s rotation - but slowly, imperceptibly, over billions of years, that influence will diminish as the Moon moves away. For CrowdScience listener Tony in the UK that idea poses another question. What if we were to look back in time? What effects did the Moon have when it was closer to Earth? Would it counteract the planet’s gravity more so that, at the time of the dinosaurs, a Brontosaurus would weigh a little less that it would if it existed now? It’s an intriguing question. And, given that it involves both the Moon AND dinosaurs, it’s one that’s got presenter Anand Jagatia really excited!

Anand begins his journey on Brighton beach on the South coast of the UK. He’s there to watch the full Moon rise - and get a few insights on Tony’s question - from astronomer Darren Baskill and astrophotographer (and cellist) Ivana Perenic.

Anand talks to Darren about the influence of the Moon’s gravity on Earth today. As they stand on the beach, with the sea lapping at their feet, they can certainly see its effect on the ocean tides. But did you know that the Moon also causes tides on the land as well? Every time it’s overhead the ground you’re standing on is higher by a few centimetres.

Professor Neil Comins, author of the book What If the Moon Didn’t Exist, explains why the tides are the reason the Moon is moving away from Earth – and it has been ever since it was first formed.

And how was it formed anyhow? We turn back time with Prof. Sara Russell from the Natural History Museum in London to discover one of the most dramatic events in the early history of our solar system... when two worlds collided.

And, of course, it helps to know what a dinosaur weighed in the first place. Anand turns to paleontologist Nicolas Campione, who’s been puzzling over the most accurate way to calculate the bulk of a Brontosaurus.

Contributors: Dr. Darren Baskill, Astronomer, University of Sussex, UK Ivana Perenic, Astrophotographer Dr. Nicolas Campione, Paleontologist, University of New England, Australia Prof. Sara Russell, Cosmic Mineralogist, Natural History Museum, UK Prof. Neil Comins, Astronomer, University of Maine, USA

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

(Image: Tyrannosaurus Rex and Spinosaurus in front of the moon - stock photo Credit: MR1805via Getty Images)

18 is the age of majority, or maturity, in most countries around the world. Depending where you live, it might be when you can vote, buy alcohol, or get married. But what's so special about 18 that makes it the beginning of adulthood? CrowdScience listener Lynda didn't feel very mature back then. She recalls a difficult decision that made her wonder what science has to say about when we’re truly grown up. How developed are we, physically, mentally and emotionally, by the age of 18? And how much does this differ between people, or from culture to culture? Presenter Caroline Steel digs around for answers with the aid of neuroscientist Sarah-Jayne Blakemore, biological anthropologist Barry Bogin, and cultural anthropologist Bonnie Hewlett. And even some teenagers. Contributors: Barry Bogin, Emeritus Professor of Biological Anthropology, Loughborough University Sarah-Jayne Blakemore - Professor of Psychology and Cognitive Neuroscience at the University of Cambridge Professor Bonnie Hewlett - Associate Professor, Cultural Anthropology, WSU Vancouver

Presenter: Caroline Steel Producer: Richard Walker Editor: Cathy Edwards Production Co-Ordinator: Ishmael Soriano Studio Manager: Neva Missirian

An apex predator is a killer. Usually large and terrifying, they enjoy the privilege of life at the top of a food chain. Nothing will eat them, leaving them free to wreak carnage on more vulnerable creatures.

In biology, it’s a term normally reserved for animals like polar bears, tigers and wolves. But CrowdScience listener Eoin wonders whether there’s a non-animal candidate for apex predator: the car. After all, worldwide, more than 1.5 million humans die on the roads each year, while pollution from traffic kills millions more. And that’s just the impact on us. What are cars doing to all the other species on this planet?

Host Anand Jagatia hits the road to investigate. En route, we’ll be picking up some scientists to help answer the question. It turns out to be so much more than a question of roadkill: cars, and the infrastructure built to support them, are destroying animals in ways science is only now revealing.

How did the wildlife cross the road? We go verge-side to test four different approaches. And we hear how cars manage to kill, not just on the roadside, but, in the case of some salmon species, from many miles away. Gathering as much evidence as possible, we pass judgement on whether the car truly is an apex predator.

Contributors: Samantha Helle - Conservation Biologist and PhD student, University of Wisconsin–Madison Paul Donald – Senior Scientist, BirdLife International and Honorary Research Fellow, University of Cambridge Zhenyu Tian – Environmental Chemist and Assistant Professor, Northeastern University

Presenter: Anand Jagatia Producer: Marnie Chesterton Reporter: Camilla Mota Editor: Cathy Edwards Studio manager: Donald MacDonald and Giles Aspen Production co-ordinator: Ishmael Soriano

(Image: Illustration of a deer in front of a car - stock illustration Credit: JSCIEPRO/SCIENCE PHOTO LIBRARY via Getty Images)

Many of us experience an inner voice: we silently talk to ourselves as we go about our daily lives. CrowdScience listener Fredrick has been wondering about the science behind this interior dialogue. We hear from psychologists researching our inner voice and discover that it’s something that begins in early childhood. Presenter Caroline Steel meets Russell Hurlburt, a pioneering scientist who devised a method of researching this - and volunteers to monitor her own inner speech to figure out what’s going on in her mind. She discovers that speech is just part of what’s going on in our heads, much of our inner world in fact doesn’t involve language at all but includes images, sensations and feelings. Caroline talks to psychologist Charles Fernyhough, who explains one theory for how we develop an interior dialogue as young children: first speaking out loud to ourselves and then learning to keep that conversation going silently. No one really knows how this evolved, but keeping our thoughts quiet may have been a way of staying safe from predators and enemies. Using MRI scanning, Charles and Russell have peered inside people’s brains to understand this interior voice and found something surprising: inner dialogue appears to have more in common with listening than with speaking.

Caroline also has an encounter with a robot that has been programmed to dialogue with itself. Which leads us to some deep questions: is our inner voice part of what makes us human, and if so, what are the consequences of robots developing this ability? Scientist Arianna Pipitone describes it as a step towards artificial consciousness.

Featuring: Professor Charles Fernyhough, University of Durham, UK Professor Russell Hurlburt, University of Nevada, Las Vegas, USA Dr Arianna Pipitone, University of Palermo, Italy Presenter: Caroline Steel Producer: Jo Glanville Editor: Cathy Edwards Sound design: Julian Wharton Studio manager: Donald MacDonald Production co-ordinator: Ishmael Soriano

(Image: Mixed Race boy looking up Credit: Jose Luis Pelaez Inc via Getty Images)

It would be quite a superpower to regrow entire body parts. CrowdScience listener Kelly started pondering this after a discussion with her friend on whether human tongues could regrow. Finding out that they couldn't, she asked us to investigate the extent of human regenerative abilities.

Presenter Alex Lathbridge travels to Vienna, a hotbed of research in this area. He meets an animal with much better powers of regeneration than humans - the axolotl. In Elly Tanaka’s lab he finds out how she studies their incredible abilities – and shows off his new axolotl tattoo.

Why can these sweet-looking salamanders regrow entire limbs while we can’t even regrow our tongues? Palaeontologist Nadia Fröbisch has looked into the evolutionary origins of regeneration, and it goes a lot further back than you might think.

And in fact, even humans are constantly regenerating, by renewing the building blocks of our bodies: cells. New cells grow and replace old ones all the time – although, in some parts of the body, we do keep hold of the same cells throughout our lives.

However, cell turnover isn’t the same as regrowing entire organs or limbs. But can we grow new body parts in the lab instead? We meet Sasha Mendjan, who creates heart organoids using our cells’ innate ability to self-organise. How far off are we from implanting organs, grown from a patient’s stem cells, back into the human body?

Contributors: Dr Elly Tanaka, Institute of Molecular Biotechnology (IMBA) Prof Martin Hetzer, Institute of Science and Technology Austria (ISTA) Prof Nadia Fröbisch, Natural History Museum Berlin Dr Sasha Mendjan, Institute of Molecular Biotechnology (IMBA)

Presenter: Alex Lathbridge Producer: Florian Bohr Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Bob Nettles

Why do we have two eyes? Two ears? Two arms and two legs? Why is one side of the human body – externally at least – pretty much a mirror image of the other side?

CrowdScience listener Kevin from Trinidad and Tobago is intrigued. He wants to know why human beings – and indeed most animals - have a line of symmetry in their bodies. Yet, beyond their flowers and fruits, plants don’t seem to have any obvious symmetry. It seems that they can branch in any direction.

Anand Jagatia sets out to find out why the animal kingdom settled on bilateral symmetry as the ideal body plan. And it takes him into the deep oceans of 570 million years ago. Paleobiologist Dr. Frankie Dunn is his guide to a time when animal life was experimenting with all sorts of different body plans and symmetries.

Frankie shows Anand a fossil of the animals which changed everything. When creatures with bilateral symmetry emerged they began to re-engineer their environment, outcompeting everything else and dooming them to extinction.

Well... nearly everything else. One very successful group of animals which have an utterly different symmetry are the echinoderms. That includes animals with pentaradial - or five-fold - symmetry like starfish and sea urchins. And that body shape poses some intriguing questions... like “where’s a starfish’s head?” Dr. Imran Rahman introduces us to the extraordinary, weird world of echinoderms.

To answer the second part of Kevin’s question - why plants don’t seem to have symmetry – Anand turns to botanist Prof. Sophie Nadot. She tells him that there is symmetry in plants... you just have to know where to look! Beyond flowers and fruits, there’s also symmetry in a plants leaves and stem. The overall shape of a plant might start out symmetrical but environmental factors like wind, the direction of the sun and grazing by animals throws it off-kilter.

And, while the human body may be symmetrical on the outside, when you look inside, it’s a very different story. As listener Kevin says, “our internal organs are a bit all over the place!” Prof. Mike Levin studies the mechanisms which control biological asymmetry. He tells Anand why asymmetry is so important... and also why it’s so difficult to achieve consistently.

Contributors: Dr. Frankie Dunn, Oxford University Museum of Natural History, UK Dr. Imran Rahman, Natural History Museum, London, UK Prof. Sophie Nadot, Université Paris-Saclay, France Prof. Mike Levin, Tufts University, Massachusetts, USA

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

(Image: Orange oakleaf butterfly (Kallima inachus) on tropical flower, Credit: Darrell Gulin/The Image Bank via Getty Images)

It's a simple metal box that moves nearly all of our goods around the world. Designed for uniformity and interchangeability, the shipping container has reshaped global trade and our lives in the nearly 70 years since its creation.

But listener Paul wants to know if these heavy steel containers could be made with lighter materials to cut down on the fuel needed to transport them, especially when they're empty. Could we make shipping containers a more efficient process and reduce the shipping industry’s sizable greenhouse gas emissions?

Host Anand Jagatia travels to Europe's largest port in Rotterdam looking for answers. Speaking to environmental scientists and industry insiders along the way, he takes a look at how the humble container might be modified to once again remake global shipping, from materials, to designs, to how it’s shipped. And thinking outside the box, we explore which innovations might benefit the whole system – from machine learning to new, carbon-free energy sources.

For an industry that’s not always quick to change, we speak with the changemakers trying to disrupt the way 90% of the stuff we buy moves, in hope of a greener future.

Featuring: Maarten van Oosten - Port of Rotterdam Authority Marc Levinson - historian, economist and author Greg Keoleian - School for Environmental Sustainability and Center for Sustainable Systems, University of Michigan Hans Broekhuis - Holland Container Innovations Trine Nielsen, Flexport Tristan Smith - University College London Elianne Wieles – Deep Sea Carriers, Port of Rotterdam

Presenter: Anand Jagatia Producer: Sam Baker Editor: Cathy Edwards Production Coordinator: Ishmael Soriano Studio Manager: Steve Greenwood

(Photo: Port of Rotterdam, Maasvlakte Deep Sea Carrier Area. Credit: Sam Baker, BBC)

When listener Watum heard about the Titan submersible implosion in the news in 2023, a question popped up in his mind: if a machine that we specifically built for this purpose cannot sustain the water pressure of the deep ocean, how do fish survive down there?

In this episode, we travel with marine biologist Alan Jamieson to the second deepest place in our oceans: the Tonga trench. Meanwhile, presenter Caroline Steel speaks to Edie Widder about the creatures that illuminate our oceans, and travels to Copenhagen to take a closer look one of the strangest deep sea creatures and its deep sea adaptations.

But even fish have their limits! Scientist Paul Yancey correctly predicted the deepest point that fish can live, and it all comes down to one particular molecule.

So is there anything living beyond these depths? Well, there is only one way to find out…

Contributors: Prof Alan Jamieson, University of Western Australia Luke Siebermaier, Submersible Team Leader, Inkfish Dr Edie Widder, Ocean Research & Conservation Association Peter Rask Møller, Natural History Museum of Denmark Prof Paul Yancey, Whitman College

Presenter: Caroline Steel Producer: Florian Bohr Editor: Martin Smith & Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Steve Greenwood

(Image: Deep-sea fish - stock photo, Credit: superjoseph via Getty Images)

CrowdScience listener Azeddine from Algeria has had bad handwriting since he was a child. In fact, it was so untidy that, when he later became a chemistry lecturer, his university students complained that they could not read his lecture notes. That was when he decided he had to do something about it. And it got him wondering… why do some of us have very neat handwriting while other people’s is almost unreadable? Why do his sisters all write beautifully when his natural style is quite the opposite? Presenter Alex Lathbridge sets out to answer Azeddine’s question. He explores the different factors which determine how well we write. How much of it is inherited? What part does family and education play? And what is actually going on in our brains when we apply pen to paper? Alex talks to anthropologist Monika Saini of the National Institute of Health and Family Welfare, Delhi, who has analysed writing styles within families and in different regions across India. She tells him about the genetic and cultural factors which seem to influence our handwriting. We also hear from neuroscientist Marieke Longcamp of Aix Marseille Université, France, who uses MRI scanning to find out which parts of our brains are involved when we write by hand. She has looked at what is happening in the brains of people who write in more than one script – for example in French and Arabic, like Azeddine. Another neuroscientist, Karin Harman James, from Indiana University, USA ,has been looking at the link between learning something by writing it down compared to typing it on a tablet or laptop. And Alex meets handwriting tutor Cherrell Avery to find out if it’s possible to improve your writing – even as an adult. Presenter: Alex Lathbridge Producer: Jeremy Grange Editor: Cathy Edwards Production Co-ordinator: Ishmael Soriano Studio Manager: Emma Harth

In many languages across the world, all nouns are classed as either male or female, or sometimes neuter. The English language, however, only signals gender in its pronouns - he, she, it or they. For inanimate objects, gender just crops up in occasional examples like ships or countries, which, for some reason, are deemed female. This lack of gender in English intrigued CrowdScience listener Stuart, since the other languages he knows all highlight whether something is male or female. Did English ever have gender, and if so, where did it go? Presenter Anand Jagatia dives into some Old English texts to uncover the idiosyncrasies of its masculine and feminine nouns, and learns why these gradually fell out of use. But why do other languages assign gender to nouns – male, female, and sometimes many more categories too? And does this affect the way we think?

Contributors: Andrew Dunning, Curator of Medieval Manuscripts, Bodleian Library, Oxford University Rachel Burns, Departmental Lecturer in Old English, Oxford University Suzanne Romaine, Professor of Linguistics, Hawaii Ida Hadjivayanis, Senior Lecturer in Swahili, SOAS University Angeliki Alvanoudi, Sociolinguist, Aristotle University of Thessaloniki Amy Bahulekar, Writer, Mumbai

Presenter: Anand Jagatia Producer: Eloise Stevens Editor: Cathy Edwards Production Coordinator: Ishmael Soriano

Buildings inspire many emotions, like awe, serenity or even dread. CrowdScience listener Siobhan was struck by this as she passed a huge apartment block with tiny windows; it reminded her of a prison. So, she asked us to investigate the feelings that buildings can trigger. Architects have long considered how the effect of buildings on their occupants or passersby: asking whether certain features elicit feelings of wonder or joy... or sadness and fear. And now modern neuroscience has started to interrogate these very questions, too. How much of the way we feel about a building is to do with its intrinsic design, and how much is due to our individual brain chemistry and life experiences? Presenter Caroline Steel talks to designer Thomas Heatherwick about his ideas for improving public spaces; enters a virtual reality simulation in Denmark to learn about the emerging field of ‘neuroarchitecture’; and finds out why people just can’t agree what makes a ‘good’ or ‘bad’ building.

Contributors: Thomas Heatherwick, Heatherwick Studios, London Professor Zakaria Djeberra, University of Aalborg Professor Lars Fich, University of Aalborg Professor Edward Vessel, City College of New York Presenter: Caroline Steel Producer: Richard Walker Editor: Cathy Edwards Production Coordinator: Ishmael Soriano Studio Manager: Duncan Hannant

(Image: Rear view of woman surrounded by old traditional residential buildings and lost in city, Hong Kong, China. Credit: d3sign via Getty Images)

How do you think about the internet? What does the word conjure up? Maybe a cloud? Or the flashing router in the corner of your front room? Or this magic power that connects over 5 billion people on all the continents of this planet? We might not think of it at all, beyond whether we can connect our phones to it.

Another chance to hear one of our favourite episodes, inspired by a question from CrowdScience listener Simon: how much does the internet weigh?

First of all, this means deciding what counts as the internet. If it is purely the electrons that form those TikTok videos and cat memes, then you might be surprised to hear that you could easily lift the internet with your little finger. But presenters Caroline Steel and Marnie Chesterton argue that there might be more, which sends them on a journey.

They meet Andrew Blum, the author of the book Tubes – Behind the Scenes at the Internet, about his journey to trace the physical internet. And enlist vital help from cable-loving analyst Lane Burdette at TeleGeography, who maps the internet.

To find those cables under the oceans, they travel to Porthcurno, once an uninhabited valley in rural Cornwall, now home to the Museum of Global Communications thanks to its status as a hub in the modern map of worldwide communications. With the museum’s Susan Heritage-Tilley, they compare original telegraph cables and modern fibre optics.

The team also head to a remote Canadian post office, so correspondent Meral Jamal can intercept folk picking up their satellite internet receivers, and ask to weigh them. A seemingly innocuous question becomes the quest for everything that connects us... and its weight!

Producer: Marnie Chesterton Presenters: Marnie Chesterton & Caroline Steel Editors: Richard Collings & Cathy Edwards Production Coordinators: Jonathan Harris & Ishmael Soriano Studio Manager: Donald MacDonald

(Image: Blue scales with computer coding terms. Credit: Alengo via Getty Images)

Snakes are often seen as slithery, slimy and scary. But these intriguing non-legged creatures have made CrowdScience listener Okello from Uganda wonder how they move – more specifically, he wants to know how they climb trees so easily, and so fast.

Presenter Caroline Steel meets snake expert Mark O’Shea to investigate the ingenious methods different snakes use to scale a tree trunk, and gets a demonstration from a very agreeable corn snake at a zoo.

Snake movement isn’t just your typical S-shaped slithering: these reptiles move in a remarkably diverse range of ways. Melissa Miller from the University of Florida explains all the range of motion snakes can employ to effectively travel along the ground as well as at height.

Caroline witnesses this in action as we pay a steamy visit to the Everglades National Park in Florida, USA, tracking pythons across the vast swamps there. We find out why understanding these pythons’ movement is vitally important for conserving the local ecosystem.

Contributors: Dr Melissa Miller, Research Assistant Scientist, University of Florida Brandon Welty, Wildlife Biologist, University of Florida Prof Mark O’Shea MBE, Professor of Herpetology, University of Wolverhampton

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

The CrowdScience team like a challenge. And listeners Jenny and Kai in the UK have come to us with a big one. They want to know how many flies have ever existed.

Flies first appeared around 270 million years ago, so presenter Caroline Steel prepares herself to calculate a very, very large number indeed. She enlists the help of Dr Erica McAlister, Curator of Flies at the Natural History Museum in London. As Erica introduces her to specimens from the Museum’s collection of over 30 million insects, they start with the basics. Like... how do you define a fly in the first place?

Caroline also explores the incredible diversity of flies… from fast-moving predators like robber flies which catch other insects on the wing to midges which are a vital part of chocolate-production; and from blood-sucking mosquitoes which transmit fatal diseases to the housefly buzzing lazily around a room.

And that leads to another fly-related question. Listener Brendan in Colombia wonders why they always fly in circles around a particular area of his apartment. For an explanation we turn to Prof. Jochen Zeil from the Australian National University who reveals that this apparently aimless behaviour is, in fact, a battle for sex.

And Collin in Barbados has e-mailed to ask how flies and mosquitoes benefit us. He’s had first-hand experience of their negative effects through contracting the disease chikungunya from a mosquito bite so he’s wondering if these insects are anything other than a nuisance. However, passionate fly advocate Erica McAlister is ready with plenty of reasons that we should be extremely grateful for them!

Contributors: Dr Erica McAlister, Natural History Museum, London Dr David Yeates, Director, Australian National Insect Collection Prof. Jochen Zeil, Australian National University Prof. Jo Lines, London School of Hygiene and Tropical Medicine

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

(Image: Close-up of insect on leaf, Kageshwori Manohara, Bagmati Province, Nepal. Credit: Aashish Shrestha via Getty Images)

It’s hard to imagine something as mind-bogglingly small as an atom.

But CrowdScience listener Alan has been attempting to do just that. All things in nature appear to be different and unique; like trees and snowflakes, could it be that no two atoms are ever the same?

Alan isn’t the first person to wonder this. Philosopher and scientist Gottfried Leibnitz had a similar idea in the 17th century; in this episode, philosopher of physics Eleanor Knox helps us unpick the very idea of uniqueness.

And with the help of physicist Andrew Pontzen, presenter Anand Jagatia zooms into the nucleus of an atom in search of answers. Listener Alan has a hunch that the constant movement of electrons means no atom is exactly the same at any given moment in time. Is that hunch right? We discover that the world of tiny subatomic particles is even stranger than it might seem once you get into quantum realms.

Can we pinpoint where uniqueness begins? And if the universe is infinite, is uniqueness even possible?

In the podcast edition of this show, we peer into that expansive universe, as we discover that the quantum world of hydrogen - the tiniest and most abundant of all atoms - allows us to observe galaxies far, far away. Featuring: Dr Eleanor Knox – King’s College London Prof Andrew Pontzen – University College London Dr Sarah Blyth – University of Cape Town Dr Lucia Marchetti – University of Cape Town

Presented by Anand Jagatia Produced by Florian Bohr Editor: Cathy Edwards Production Coordinators: Ishmael Soriano and Liz Tuohy Studio Manager: Emma Harth

(Photo: Twelve snow crystals photographed under a microscope, circa 1935. Credit: Herbert/Archive Photos/Getty Images)

Listener Julie lives close to the coast in New Zealand and wants to know why the water that washes up on the beach isn't fresh. How exactly does all that salt get into the world's oceans?

In India, a country where salt became symbolic of much more than well-seasoned food, host Chhavi Sachdev visits coastal salt farms and a research institute dedicated to studying all things saline, to better understand our relationship with salty seas.

The team also ventures to a very briny lake on the other side of the globe in Salt Lake City, Utah, to learn how salt makes its way into water bodies.

Speaking to an expert in deep sea exploration, we learn how hydrothermal vents may play a role in regulating ocean saltiness, and how much the field still has to explore.

Meanwhile, listener Will wants to know how much melting ice sheets are affecting ocean salinity. But ice melt isn’t the only thing affecting salt levels when it comes to the impacts of climate change.

And... how many teaspoons of salt are in a kilogram of sea water anyway? We do the rigorous science to answer all these salient saline questions.

Featuring: Deepika - small scale salt farmer Mark Radwin - PhD candidate in geology and geophysics at the University of Utah Brenda Bowen - Geology & Geophysics, Atmospheric Sciences, University of Utah Chris German - Geology & Geophysics, Woods Hole Oceanographic Institution Prasan Khemka - Chandan Salt Works Paul Durack - Lawrence Livermore National Laboratory Bhoomi Andharia - Central Salt & Marine Chemicals Research Institute

Presenter: Chhavi Sachdev Producer: Sam Baker Editor: Cathy Edwards Production Coordinator: Liz Tuohy Studio Manager: Sarah Hockley

(Photo: Shiv Salt Works, Bhavnagar, Gujarat in India. Credit: Chhavi Sachdev, BBC)

CrowdScience listener Eleanor was lying in bed one rainy evening, listening to the radio. She lives in New Zealand, but happened to hear a weather forecast that told her it was raining in the UK too.

She started wondering: could it be the same rain falling there and outside her window in New Zealand? Can a raindrop really travel all the way around the world?

There are a number of routes the droplet could take, including traveling as moisture in the air. Presenter Caroline Steel meets meteorologist Kei Yoshimura, who puts his powerful weather simulation to work plotting the raindrop’s journey through the sky.

What if the raindrop falls along the way and gets trapped? Where might it end up? Hydrologist Marc Bierkens talks Caroline through the detours it could take, ranging from short stop-offs in plant stems to extremely long delays in deep groundwater.

Finally, could the drop of water make it to New Zealand by circulating through the world’s ocean currents? Oceanographer Kathy Gunn maps the droplet’s path through the ocean – and explains how climate change might affect its journey.

Featuring: Prof. Kei Yoshimura, Professor of Isotope Meteorology, University of Tokyo Prof. Marc Bierkens, Professor of Earth Surface Hydrology at Utrecht University Dr. Kathy Gunn, Lecturer in Climate Sciences at the University of Southampton

Presenter: Caroline Steel Producer: Phil Sansom Editor: Cathy Edwards Production Co-ordinator: Liz Tuohy Studio Manager: Tim Heffer Additional recording: Knut Heinatz

(Photo: Textures of rain on the surface of the ocean. Credit: Philip Thurston/Getty Images)

It’s often said that fine wine gets better with time, and this week’s oenophile listener Jeremy has a cellar full of dust-covered bottles. He is curious whether chemistry can account for the range of flavours that develop as wine matures, but also wonders why some of it tastes like vinegar if you leave it too long? We head off to the Bordeaux region of France, where vines were planted almost 2,000 years ago. Here, winemakers are joining forces with scientists to better understand wine ageing, a process so subtle and intricate that even the scientists refer to it as magic. In the world-famous vineyards of Chateau Margaux, presenter Marnie Chesterton learns that the key ingredient for good grapes is a sandy soil type; and that in this part of France, the warming climate is actually having a positive effect on the vines, which need very little water to thrive. Over in the lab, we meet the chemist mapping the molecules responsible for aromas associated with a well-aged Bordeaux. Featuring: Philippe Bascaules, Chateau Margaux Prof Cornelis van Leeuwen, Bordeaux Sciences Agro Dr Stephanie Marchand-Marion, ISVV Alexandre Pons, ISVV Presented by Marnie Chesterton Producer – Marijke Peters Editor – Cathy Edwards Production Co-ordinator – Liz Tuohy Studio Manager – Sarah Hockley

(Photo: Aged bottles on wine racks in a cellar. Credit: Morsa Images/Getty Images)

The Blue Ridge Parkway is 469 miles of beautiful vistas, a mountainous road that winds from Virginia to North Carolina in the USA. The route is peppered with elevation signs, telling you how many metres above sea level you are. Which has CrowdScience listener Beth wondering: as we are told that sea level is rising, will all the elevation signs need repainting?

It’s a task she’s passed over to the CrowdScience team, who like a difficult challenge. 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. The east coast of America has a different sea level to its west coast. And as host Marnie Chesterton discovers in Finland, in some parts of the world the land is being pushed up, so sea level is actually falling.

In fact, when nothing on earth - not the sea, the shore or the mountains - seems to be stable or constant, the question of what you measure from and to becomes incredibly tricky. But that hasn’t stopped oceanography and geography scientists risking life and fingers to use an ever-evolving array of technologies to find answers. In this show we find out why they care so much, and why we should too.

Featuring: Dr Paul Bell – National Oceanography Centre, Liverpool, UK Dr Severine Fournier – NASA Jet Propulsion Laboratory / California Institute of Technology Dr Jani Särkkä – Finnish Meteorological Institute Khimlal Gautam – Mountaineer and Chief Survey Officer, Government of Nepal Dr Derek van Westrum – National Oceanic and Atmospheric Administration, USA

Presented and produced by Marnie Chesterton Editor – Cathy Edwards Production Co-ordinator – Liz Tuohy Studio Manager – Steve Greenwood

(Photo: Sea Level Elevation Sign in Death Valley, California. Credit: Mitch Diamond/Getty Images)

Prayer and meditation are key features of religious and spiritual practices around the world, suggesting they’re intimately linked to the human condition. But what is going on in the brain during prayer? And is praying beneficial for our mental health?

CrowdScience listener Hilary is keen to find answers to such questions. She’s a counsellor with a strong Christian faith, and is curious to know whether science can illuminate religious and spiritual practices.

Presenter Caroline Steel talks to neuroscientists researching how our brains respond to prayer and meditation; and practices mindfulness herself to explore its similarities to prayer. She discovers that having a relationship with God may depend on more than religious practice. And is there a ‘spiritual part’ to our brains? Or is prayer just one activity among many - like going for a walk or playing music - that can have similar effects on our state of mind?

Featuring: Professor Andrew Newberg, Director of Research Marcus Institute of Integrative Health, Thomas Jefferson University and Hospital, USA Tessa Watt, mindfulness teacher Ven. Hin Hung Sik, Centre of Buddhist Studies, University of Hong Kong Dr Junling Gao, Centre of Buddhist Studies, University of Hong Kong Dr Blake Victor Kent, Westmont College, USA

Presenter: Caroline Steel Producer: Jo Glanville Editor: Cathy Edwards Studio Manager: Tim Heffer Production Co-ordinator: Liz Tuohy

(Photo: A crowd of people praying. Credit: Digital Vision/Getty Images)

Mosquitoes are responsible for more human deaths than any other animal. These tiny creatures transmit many diseases, but the most devastating is malaria. It kills over half a million people every year, most of them children.

So why are people still dying of malaria in such large numbers, when so much time and money has been invested in trying to eradicate it? What do we know about mosquitoes and malaria, and what do we still need to learn? CrowdScience visits Malawi, one of the African countries leading the way against malaria, with the rollout of the world’s first malaria vaccine programme.

Presenter Caroline Steel is joined by a live audience and a panel of experts: Wongani Nygulu, Eggrey Aisha Kambewa and Steve Gowelo. Together they explore questions from our listeners in Malawi and around the world, like why female mosquitoes feed on blood while males drink nectar; why some people are more likely to be bitten by mosquitoes than others; and how we might modify the insects’ DNA to stop them spreading diseases.

About half a million children across Malawi have been vaccinated since 2019. We visit a clinic in nearby Chikwawa to meet the staff involved in the vaccination programme there, and the mothers embracing the opportunity to protect their babies against this deadly disease.

Recorded at Malawi Liverpool Wellcome Trust (MLW), Blantyre, Malawi.

Contributors: Dr. Wongani Nygulu, Epidemiologist, Malaria Alert Centre Eggrey Aisha Kambewa, MLW entomologist, MLW Dr. Steve Gowelo, University of California San Francisco Malaria Elimination Initiative

Presenter: Caroline Steel Producer: Jeremy Grange Researcher: Imaan Moin Additional Recording: Margaret Sessa Hawkins & Sophie Ormiston Editor: Cathy Edwards Production Co-ordinator: Liz Tuohy

(Photo: A mosquito, that is silhouetted against the moon, bites a human arm. Credit: LWA/Getty Images)

When CrowdScience listener Israel from Papua New Guinea received a bad grade on a maths test in third grade, he looked around the class and realised that almost all the other students had received a better result. Since then, he has always wondered: why are some people better at maths than others? And Israel isn’t the only one to think about this: our listeners from all over the world describe their relationships with numbers, which run the full gamut from love to hate. So are we all in control of our own mathematical fate, or are some people just naturally bad at it? Presenter Anand Jagatia hears about studies of identical and non-identical twins showing how genetics and environment interact to shape our mathematical abilities. Our numerical abilities are not set in stone. It’s always possible to improve, and getting rid of negative feelings and anxiety around maths could be the key, says psychologist Iro Xenidou-Dervou. Some countries seem to support children’s maths skills better than others. China and Finland both rank highly in international league tables; education experts in both countries discuss whether there are any keys to a successful mathematics education. And there is something underlying our ability to do maths in the first place: our number sense. We hear what happens when this number sense does not work as intended – and what can be done about it. Contributors: Professor Yulia Kovas – Goldsmiths University of London, UK Professor Pekka Räsänen – University of Turku, Finland Assistant Professor Zhenzhen Miao – Jiangxi Normal University, China Dr Iro Xenidou-Dervou – Loughborough University, UK Professor Brian Butterworth – University College London, UK Presented by Anand Jagatia Produced by Florian Bohr Editor: Cathy Edwards Production Co-ordinator: Liz Tuohy Studio Manager: Jackie Margerum

(Photo: Boy scratching head in front of blackboard. Credit: Jose Luis Pelaez Inc/Getty Images)

Coastlines around the world are changing, causing serious problems for the many communities living near the sea, as well as vital and fragile coastal ecosystems.

In the second of a two-part special on coastal erosion, CrowdScience explores the best ways to tackle this problem. Presenter Caroline Steel visits the Caribbean island of Puerto Rico to see the various methods they use to protect their coasts.

First up: ‘riprap’ – rocks strategically placed to keep the encroaching sea at bay. The problem is, while it protects the area immediately behind the rocks, riprap can exacerbate erosion nearby.

But there are other, more nature-friendly solutions, including sand dune restoration. Caroline picks up her shovel and helps to re-plant dunes, destroyed in the past by erosion as well as sand extraction for the construction trade. The roots of these plants stabilise the dunes, while building boardwalks prevents further damage from humans.

Nature also offers the perfect offshore protection against coastal erosion: coral reefs. These are the first line of defence in absorbing the power of the ocean’s waves. Down on the beach, we see for ourselves just how effective they are. The reefs face threats, but restoration plans are afoot. We visit a nursery that grows corals to plant out on the reefs – and find out about corals’ surprising cannibalistic tendencies in the process.

Featuring: Professor Robert Mayer - Director of Vida Marina, Center for Conservation and Ecological Restoration, University of Puerto Rico Nada Nigaglioni - Biology student, University of Puerto Rico Ernesto Diaz - Caribbean Regional Manager at TetraTech Dr Stacey Williams - Executive Director, ISER Caribe

Presenter: Caroline Steel Producer: Hannah Fisher Editor: Cathy Edwards Production Co-ordinator: Liz Tuohy Studio Manager: Emma Harth

(Photo: Coast restoration measures at Ultimo Trolley Beach, Puerto Rico. Credit: BBC)

Around the world, coastlines are constantly changing due to the power of waves, currents and tides. Coastal areas are also some of the most heavily populated and developed land areas in the world. So it’s not hard to see how the natural process of coastal erosion can cause serious problems for us.

It’s an issue that’s been bothering CrowdScience listener Anne in Miami Beach, Florida. She can see the beach from her window and wonders why after every storm, several trucks arrive to dump more sand on it.

In this first of two programmes, CrowdScience visits Anne’s home in south Florida and finds out how erosion threatens Florida’s famous beaches. Caroline Steel speaks to geoscientist Dr Tiffany Roberts Briggs and hears why it’s such a problem for this tourist-reliant state. Tiffany explains the delicate balance between natural processes and human infrastructure.

Meanwhile, the Caribbean island of Puerto Rico declared a state of emergency in April 2023 due to coastal erosion. Caroline witnesses the impacts of erosion first-hand, as Ruperto Chaparro shows her abandoned houses crumbling into the sea.

But how can we quantify the rate of erosion? Dr Kevian Perez in the Graduate School of Planning at University of Puerto Rico explains the methods they use to monitor Puerto Rico’s coastlines, and how they are evaluating the effectiveness of different mitigation methods.

However, some of the methods used to protect coastal communities from the encroaching sea have done more harm than good. So what are the best ways to tackle this problem? That’s what we’ll be exploring in next week’s programme.

Presenter: Caroline Steel Producer: Hannah Fisher Editor: Cathy Edwards Production Co-ordinator: Liz Tuohy Studio Manager: Steve Greenwood and Bob Nettles

Featuring: Dr Tiffany Roberts Briggs, Associate Professor at Florida Atlantic University Ruperto Chaparro, Director of Sea Grant Programme, University of Puerto Rico Anabela Fuentes Garcia, Villa Cristiana community leader Dr Kevian Perez, researcher at the Coastal Research and Planning Institute of Puerto Rico at the Graduate School of Planning

(Photo: Puerto Rico after Hurricane Maria. Credit: Orlando Sentinel/Getty Images)

How do we know where a sound is coming from?

Another chance to hear this ear-opening episode, exploring a question from CrowdScience listener Chiletso. One day, he heard his son bounce a ball and instantly knew the direction it was travelling. How?

Anand Jagatia sets out to discover what makes left, right, up and down sound so different.

First, he gets blindfolded, so Alan Archer-Boyd, former auditory scientist and lead engineer at BBC R&D, can put his sound localisation skills to the test. It turns out that having two ears and pinnae, those flappy bits of cartilage on the side of your head, help a lot.

Professor Eric Knudsen shares how the barn owl’s asymmetrical ears allow it to hunt mice, even in complete darkness.

And Anand uncovers how far he can push his own spatial hearing. Blind activist and researcher Thomas Tajo teaches him how to echolocate like a bat, and Dr Lore Thaler explains what is going on in the brain of experienced echolocators.

This programme was originally broadcast in March 2023.

Presented by Anand Jagatia Produced by Florian Bohr for the BBC World Service

Image: Boy with hands at his ears Credit: Silke Woweries/Getty Images

For some it's a way to get closer to God, for others a tried and tested way to lose weight - but listener Amine wants to know if fasting has any other, unexpected health benefits? So presenter Marnie Chesterton cuts down on cookies and investigates the science behind low-calorie or time-restricted eating. She hears how some cells regenerate when we're deprived of food, which one researcher says could reduce breast cancer rates. And she finds out what happens in our brains when our bodies rely on our own fat reserves for fuel. Presenter: Marnie Chesterton Producer: Marijke Peters

(Image: Clock on an empty plate. Credit: Getty Images)

Why is it that computers are so much faster than brains at some tasks?

Or could human brains one day be used to better effect? Listener Praveen from India was wondering how it can be that supercomputers are so very powerful compared to the human minds that created them. So CrowdScience, with the help of a small voice-activated guest presenter, is off to discover how the first computers remembered what they were told, how a million processors are being connected together to mimic a small percentage of a human brain, and how the mind-boggling speeds of modern computing is enabling the current leaps in artificial intelligence.

Producer: Alex Mansfield Presenter: Marnie Chesterton

Speakers: Sarah Baines, David Lewis - Museum of Science and Industry, Manchester James Sumner, Steve Furber - University of Manchester Aldo Faisal - Imperial College, London.

(Photo: 3D transparent human head and brain image. Credit: Getty images)

Kenyan listener Docktor can’t help himself. When music is playing he must move to the beat and he wants to know why. What role does dance play in human evolution? And what does dance mean to us? To help answer the many twists and turns in Docktor’s questions, the CrowdScience team heads to one of the most vibrant and diverse dance scenes in the World, Havana in Cuba. For Cubans dancing is at the heart of their cultural identity. They tell stories, bond with others, practice religion and celebrate their African ancestry through dance ¬– which came to Cuba with the slave trade.

For all humans, dancing is intimately connected to our love of music and is likely to be one of our oldest cultural practices. But why would our ancestors have wasted energy on what superficially seems to serve no survival benefits? Evolutionary anthropologist Bronwyn Tarr tells us that one clue lies in the brain. When we dance with others our brains reward us with a cocktail of feel-good hormones and this likely leads to profound social effects.

Presenter Anand Jagatia gets challenged on the dance floor, discovers how deeply rooted dance is in Cuban society and why we should dance more.

Presenter: Anand Jagatia Producer: Louisa Field

(Image: Dancers in Cuba)

Humans have the potential to eat pretty much anything – but the reality is we don’t. Wherever we live in the world, we eat just a small fraction of the foodstuffs available and show strong preferences for certain foods over others. Those preferences can change dramatically from person to person, or as the saying goes – one man’s meat is another man’s poison. Then at the extreme end of the spectrum you get so-called ‘fussy eaters’ who reject so many foods that they are confined to beige diets of crisps, crackers and cereal.

So why do we show such different preferences for food? And why are some people fussier than others? That’s what CrowdScience listeners Orante Andrijauskaite in Germany and Anna Nicolaou in Belgium would like to know, and what Datshiane Navanayagam is off to find out.

She discovers how both biology and culture shape whether a food is disgusting or delicious and learns why we should stop giving children a hard time about finishing their dinner. She also learns how global cuisines evolved and what that can teach us about helping fussy eaters to overcome their food fears.

Presenter: Datshiane Navanayagam Producer: Anna Lacey

(Photo: Fried Bugs in Bangkok night market. Credit: Getty Images)

Carbon dioxide levels are far higher than at any other point in human history, thanks to our reliance on burning fossil fuels. But having pumped huge amounts of CO2 into the air, are there ways to get it back out again? If so, where would we put it all? And the big question: can that help solve our climate change problem, or is it a distraction from the urgent task of reducing our emissions?

When CrowdScience delved into ancient carbon dioxide levels last year, it sparked a flurry of emails from our listeners asking these questions and more, so this week we investigate our options for restoring equilibrium to our atmosphere. Since the CO2 came from deep underground - in the form of coal, oil and gas - can we put it back there? We travel to Iceland where they’re capturing carbon dioxide directly from the air - and turning it into rock. Presenter: Marnie Chesterton Producer: Cathy Edwards

(Photo: Nesjavellir geothermal power plant in Iceland. Credit: Getty Images)

Short-sightedness is reaching epidemic proportions around the world. The way things are progressing, one-third of the world’s population – 2.5 billion people - could need glasses by the end of the decade. And scientists are beginning to understand why: children spend too much time indoors, bent over screens and books. Marnie Chesterton travels to Singapore, where rates of myopia are one of the highest in the world and to see how the government is curbing the condition with an array of tools, from eye-drops to sunshine remedies.

She does so in the hope of better understanding whether screens are bad for children’s eyes, a question raised by a concerned Mexican father, Fernando, about his two-year old daughter.

Presenter: Marnie Chesterton Producer: Graihagh Jackson

(Photo: A little girl wearing headphones while using a digital tablet at home. Credit: Getty Images)

Will gravity on earth ever change? Why do insects fly towards the light? Is the plasma in a TV the same as plasma in a fusion reactor? Why are mosquito bites so itchy? What does the Higgs boson do for the Universe? In a Q+A special, Marnie Chesterton is joined by scientists Malcolm Fairbairn, Kate Lancaster and Erica McAlister to tackle a selection of questions from the CrowdScience inbox.

Presenter: Marnie Chesterton Producer: Alex Mansfield

(Photo: Alates insects light bulb and night. Credit: Getty Images)

Dementia affects nearly 50 million people worldwide – but doctors are still struggling to find a cure. CrowdScience investigates why this particular group of brain diseases are so hard to treat, from the difficulties around diagnosis to why the drugs just don’t currently work.

In the absence of a medical solution is it time to take a new approach? As geneticists develop tests to predict who might develop brain disease, there are others focusing on better care for those who already have it. Presenter Bobbie Lakhera visits a village in the Netherlands helping sufferers live longer independently, and hears how music projects improve non-verbal communication.

Presenter: Bobbie Lakhera Producer: Marijke Peters

(Photo: Neurology research examining the neurons of a human head to heal memory loss or cells due to dementia. Credit: Getty Images)

Since the end of the 19th century, scientists have been predicting we would be eating a meal in a pill, but is it a serious answer to the world’s food problems? That’s what Australian listener Bridget is wondering and whether it’s possible to produce an artificial food source that can provide all the nutrients for healthy human life.

With increasing urbanisation, diets are changing and estimates suggest food production will have to increase some 60 percent by 2050 to keep up with demand. But can we provide all that extra food with limited natural resources and traditional farming methods?

First, Marnie Chesterton finds out what artificial food is currently available and whether the existing products are healthy. And while a meal in a pill might sustain our bodies, will it sustain our minds? The experience of eating involves so much more than simply taking in the right nutrients, as Marnie discovers at the Gastrophysics Chef’s Table, a restaurant and multi-sensory dining experience. On the menu is jellyfish, a possible alternative source of food for the future. It’s in plentiful supply in our oceans, but like eating insects, the thought of it may be disgusting to some, so Marnie explores how sensory-driven strategies can be used to make these food sources more appealing.

CrowdScience also visits the future of farming: A hydroponic vertical farm called Growing Underground, which is built in World War Two air-raid shelters under London. Using LED lighting instead of sunlight, leafy vegetables grow very quickly and need very little space. With higher crop yields per square metre than traditional farming, vertical farms allow fresh produce to be grown in urban centres with less impact on the environment.

Hydroponic farming is something the European Space Agency is also experimenting with as part of Project Melissa, which is developing a closed loop ecological system - using rats instead of astronauts - aimed at one day helping us grow fruit and vegetables on Mars. Listen to the podcast version of the programme to hear this interview.

Producer: Helena Selby

(Photo: Pills on a plate. Credit: Getty Images)

Listener Nikolai sends CrowdScience hunting through space and time with his deceptively simple question. Can we find perfect stillness? You are probably reading this sentence whilst standing or sitting still. So is it a daft question? We discover that there are no simple answers as we unravel the science of motion, which tells us that we cannot always trust our senses to tell us ‘the truth’ about the natural world.

The ancient Greeks believed it was the sun that rises and sets each day and this idea remained until the 16th century astronomer Nicolaus Copernicus showed us that this an illusion – that we are the ones in motion, orbiting the Sun. Later, through the work of Isaac Newton and then Albert Einstein, scientists came to the conclusion that nothing in the universe can ever be truly still. Except perhaps, the fastest thing in the universe – light.

Confused? Don’t worry, so is Marnie Chesterton who sets out to explore not just the science of stillness but also the physics of stopping. To satisfy listener Nikolai’s curiosity about motion in space, CrowdScience also travels to ESA’s European Space Research and Technology Centre in the Netherlands. Here we find out how you stop a space craft and hear the story of when things got prickly for astronaut Tim Peake and his crew when docking at the International Space Station.

Presenter: Marnie Chesterton Producer: Louisa Field

(Photo: Astronaut wearing pressure suit against a space background. Credit: Getty Images)

Are you the master of your own decisions? Independent-minded? A free spirit? Like it or not, the answer is probably no - as we are profoundly influenced by the people around us. But why do humans follow the crowd? CrowdScience listener Cath Danes wants to know and this week we are going to be giving her answers at the BBC’s Free Thinking Festival in Gateshead.

Marnie Chesterton is joined by a crack team of neuroscientists and psychologists, who reveal the secrets behind our inner sheep. We also run an experiment to find out whether you should trust the wisdom of the crowds with life’s big decisions.

Presenter: Marnie Chesterton Producer: Anna Lacey

(Photo: A flock of sheep being herded in a pasture. Credit: Getty Images)

Unlike nuclear fission power stations, which leave harmful radioactive waste to be stored or disposed of for thousands of years, a nuclear fusion power plant would create precious little burden on future generations. The fuel source would be seawater, and the energy created limitless.

Back in the 1950s, the technology to “tame the hydrogen bomb” seemed just a few decades away from practical deployment, and governments across the divide of the cold war shared the challenges, costs and laboratories.

But to the outsider, it might look like progress has been slow. In 1997 the Joint European Torus at Culham in the UK set the world record for energy released from a controlled fusion reaction, but even that was less than the energy was put in.

Keeping the plasma – the super-hot atoms of exotic types of hydrogen – at temperatures many times the temperature of the sun safely in place inside a magnetic field is not a trivial task.

Last year construction of the International Experimental Thermonuclear Reactor, ITER, reached its halfway point at its huge home in France, and if all goes to plan it should produce its first plasma by 2025. The hope is that operational fusion reactions will take place within a decade after that, paving the way for its successor DEMO - which would actually generate electricity - to be built sometime before 2050.

But in parallel with the big intergovernmental roadmap, in recent years a number of small commercial startups have joined the race to achieve commercial fusion energy. With their various different approaches and more ambitious timelines, will the private sector beat the publicly funded science to the goal?

Presenter: Bobbie Lakhera Producer: Alex Mansfield

(Photo of ITER Organization, with permission)

Humans have used dogs' excellent sniffing talents ever since our ancestors figured out that canine companions could help them track down their next meal.

But what about other animals? Can they take us beyond the limits of our own senses? That's what CrowdScience listener Beth wants to know, so we obligingly try to sniff out some answers.

After immersing ourselves in the world of insect senses at our local zoo, we visit an insect lab in Germany to find out whether sniffer bees could take over from sniffer dogs. And could ants help us fly the drones of the future? We meet the scientists trying to turn ant vision into computer code, to send robots into places GPS can't reach.

Presenter: Nastaran Tavakoli-Far Producer: Cathy Edwards

(Photo: A bee on a human finger. Credit: Getty Images)

A cacophony of singing and screaming creatures’ accents are explored to answer: Can animals of the same species from different places communicate with each other? Presenter Geoff Marsh tries to identify how different these calls really sound for CrowdScience.

From wolves to birds to whales and chimpanzees, most animals use sound to communicate, but if groups in different places vocalise in different ways, they may not be able to communicate with others.

CrowdScience questioner, Kitty, sets us on an exploration of the vast and varied world of animal communication with inspiration from her dog Monty.

Presenter: Geoff Marsh Producer: Rory Galloway

(Photo: Three wolves howling on a cold day. Credit: Getty Images)

From worms who time their mating ritual with an inner lunar calendar, to how full moons could cause cows to give birth early. Listener Andreas sends CrowdScience on a mission to separate fact from fiction.

Presenter: Marnie Chesterton Producer: Marijke Peters

Picture: The moon rises over Kadam mountain in Uganda, on January 31, 2018, during the lunar phenomenon referred to as the 'super blue blood moon'. Credit: Yasuyoshi Chiba / AFP / Getty Images

Scientists have been searching for dark matter for 80 years, so CrowdScience wondered whether they could find it faster. Armed with a boiler suit, hard hat and ear defenders, Marnie Chesterton travels over a kilometre underground into a hot and sweaty mine to see how we could catch dark matter in action. She investigates various theories as to what it might be with popping candy and gazes at galaxies to determine how we know it exists in the first place. But most importantly, she questions whether it really matters. And, as our Singaporean listener Koon-Hou askes, what impact would finding it have on our everyday lives?

Presenter: Marnie Chesterton Producer: Graihagh Jackson

(Photo: Finding dark matter could have galactic implications. Credit: Getty Images)

Carbon is special, but is it necessarily the unique building block of life in the universe? Science fiction has long speculated on non-carbon biochemistries existing in the universe – notably in the work of authors such as Isaac Asimov as well as in the popular American TV series Star Trek, which once featured a rock-munching, silicon-based life form called ‘Horta’.

Marnie Chesterton explores the real science behind this intriguing idea and wonders whether in the current search for Earth-like planets elsewhere in the galaxy, we should be looking at completely different possible sets of rules when it comes to the hunt for life?

Producer Alex Mansfield Presenter Marnie Chesterton

(Photo: Saturn viewed from Titan moon. Credit: Getty Images)

How far can you see? A few kilometres down the road? Or do you struggle to see past the end of your own nose? Well one listener thinks he might be able to see 15 quintillion miles away... but can he really? Marnie Chesterton and Bobbie Lakhera are on the case for this week’s multi-question human body special. As well as delving into the power of vision, they also discover why male mammals have nipples despite not needing to breastfeed, and Marnie puts herself in a giant refrigerator in the name of finding out why some people feel the cold more than others.

Presenter: Marnie Chesterton Producer: Anna Lacey

Meet the entrepreneurs turning bugs into food and get top tips on how to cook them. In this week’s episode we return to the topic of edible insects and the story of Kahitouo Hein’s caterpillar factory in Burkina Faso, West Africa. Kahitouo is trying to turn a traditional food like the shea caterpillar, available for just a few weeks a year, into a year-long sustainable staple for the whole population.

We also put your questions about edible insects directly to the researchers in Burkino Faso. Discover the best way to cook a bug, explore the curious effects of hornet venom and find out whether eating insects is better for the environment then eating red meat.

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Anand Jagatia Producer: Louisa Field

(Photo: Worker at Kahit’s factory cooking caterpillars)

Most of us instinctively know when someone’s singing and when they’re talking. But since music and speech are both just sounds, how do our brains tell them apart? This week’s question comes from Eugene, a music teacher in Northern Ireland, who often hears music in people’s speech, and wonders why.

Step forward, the ‘speech-to-song illusion’. This curious phenomenon means that when certain spoken phrases are repeated, they turn into music as if by magic. We talk to the Diana Deutsch, the scientist who discovered this illusion, and find out what it reveals about how the brain is adapted to understand both music and speech.

But are some languages more musical than others? Many people around the world speak tone languages, where the pitch of a word affects its meaning. One such language is Dinka, spoken in South Sudan; we meet a Dinka speaker and hear how respecting the melody of the language is essential when writing songs.

Presenter: Datshiane Navanayagam Producer: Cathy Edwards

Dinka recordings courtesy of Elizabeth Achol and Anyang Malual

(Photo:Young woman listening to music on yellow headphones. Credit Getty Images)

Dogs have been living and working with humans for thousands of years. But they’re much more than just pets. As any dog owner will tell you, the bond we have with our canine friends is often so strong that they feel more like family.

So how is it that dogs have come to fit so seamlessly into human life?

That’s what CrowdScience listener Peter Jagger in the UK wants to know, and Marnie Chesterton is off to sniff out some answers. She starts by revisiting a previous episode of CrowdScience based in Sweden, where she saw the dog-human bond come alive during a moose hunt. She then heads to the Dog Cognition Centre in Portsmouth to discover how a unique and often unconscious communication system helps our dogs to understand us. Finally, Marnie finds out about the fate of dogs that are no longer wanted by their humans. After thousands of years of domestication, can they ever live without us?

Presenter: Marnie Chesterton Producer: Anna Lacey

(Photo: Image of young girl with her dog, alaskan malamute. Credit: Getty Images)

Crowdscience revisits the evidence on the best forms of biometric identification. Earlier in the year we explored digital fingerprints, gait (walking style) recognition and iris scanners. Today presenter Anand Jagatia looks at systems which use your face and your voice to identify you. One airline is currently testing facial recognition in airports as a means of replacing your passport. Meanwhile, Anand tries to fool a speech recognition system that measures over a thousand characteristics of your voice in order to protect your identity. But will it be able to cope if you have a cold?

Presented by Anand Jagatia Produced by Marijke Peters.

Picture: Facial Recognition Credit: Getty Images

Reindeer castration, plants get chatty and more quirky science revealed in this Christmas special of CrowdScience where we will also be hearing from the people that make this series possible. That’s you – our listeners.

CrowdScience has been on air for just over a year which means we’ve had over 60 adventures. Every time we put a show together there’s a heart-breaking process where amazing facts we wanted to share end up on the cutting-room floor. To celebrate the holidays we’ve gone scavenging for the best untold stories, edgy science facts and incidents from behind the scene. Presenter: Marnie Chesterton Producer: Louisa Field

Picture: Reindeer in Snow Credit: Getty Images

It lurks behind sofas and collects in corners, apparently appearing from nowhere. But what is household dust? And should we bother sweeping it away? That’s what Australian listener Moshe wants to know and what Marnie Chesterton is off to find out for this week’s CrowdScience. She embarks on a mission to discover not only what dust is made of, but whether it poses any health risks. Although most people sweep it away without a thought, dust contains all sorts of secrets about our habits and everyday lives. Marnie finds out how dust can reveal the pets you keep, the chemicals in your surroundings, the location of your house and how fecal bacteria can uncover whether more men or women live in your home.

Presenter: Marnie Chesterton Producer: Anna Lacey

(Image: Woman Vacuuming Up Dust. Credit: Getty Images)

Trees are old – they transcend human generations – but are they the oldest living things on Earth? This story began in June 2017 when we explored a question sent in from CrowdScience listener William. Many of you got in touch after the programme with questions of your own. So we’re revisiting our trees programme but also exploring another question from listener James, who wants to know what, pound for pound or gram for gram, is the strongest animal alive on Earth today? Marnie Chesterton wrestles with one of them and – spoiler alert – it’s not a gorilla.

Presenter: Marnie Chesterton Producers: Jen Whyntie

(Photo: Kumbuka, a 15-year-old western lowland gorilla. Credit: Oli Scarff/Getty Images)

Dodos are dead, but are they gone forever? Reviving extinct species is a trope of science fiction, but real-life scientists are working on every stage of the problem today. Meeting scientists focused on uncovering ancient animal genomes, or reviving individual cells to conserve species still around, Marnie Chesterton seeks out whether new technologies might, just possibly, bring back the iconic dodo. But what would it take to bring back that most iconic of extinct species? Following listener Rachel’s question, CrowdScience gets to grips with the dodo’s past, and finds out what’s left of this iconic bird, meeting the scientists inadvertently piecing it back together.

Presenter: Marnie Chesterton Producer: Rory Galloway

Picture: An accurate reconstruction of nesting Dodos Photo Credit: Dr Julian Hume

How does technology affect how we fall in love? Crowdscience travels to India to answer listener Erin’s questions about the impact of the internet on our search for soulmates. We meet the traditional matchmaker who says her service provides security in an era of digital fraud. And ask whether computer algorithms are the best way to help people make permanent romantic connections?

Presenter: Chhavi Sachdev Producer: Marijke Peters

(Photo: A couple kiss while taking a selfie. Credit: Getty Images)

Some of us want to be up with the larks, while others are more like night owls. But is our preference down to our genes, or more to do with habits and surroundings? We set out to find the answers, inspired by a question from Kira, a night owl CrowdScience listener in Philadelphia, USA.

Our daily, or circadian, body clocks are a hot topic of discussion at the moment - this year’s Nobel Prize for Medicine went to three scientists who discovered the gene that makes these clocks tick. To answer our listener’s question, we need to know why different clocks tick at different rates, so we visit a specialist sleep centre to see how having a slow-ticking clock makes it hard for you to leap out of bed in the morning.

And the morning sun helps all of us regulate our daily rhythm, so what happens when it doesn’t rise at all? We travel to Tromsø, in the far north of Norway, to see how morning and evening types fare during the long polar nights - and meet the reindeer who seem to be able to switch off their daily clocks altogether. Meanwhile down near the equator, we hear about the hunter-gatherer community in Tanzania where there’s nearly always someone awake.

Sami song, the joik of Ráikku-Ánte, is performed by Ken Even Berg

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Anand Jagatia Producer: Cathy Edwards

(Image: L - Women smiling on a run R - Women DJ. Credit: Getty Images)

Sometimes our memory fails us and we wish facts would just stick better. Listener Mothibi is a student and has spent three years trying to remember as much as possible for his exams. He wants to know how he can train his brain to better to remember things – and does the brain have a limit on how much stuff we can cram into it?

To find the answers presenter Marnie Chesterton seeks help from memory magician, Simon, at the European Memory Championship. Using the loci technique she accomplishes a memory feat she didn’t think possible. Thought to have been developed by the Greeks, the loci method is a technique that enables the brain to remember extraordinary amounts of information. It turns out, we all have the right wiring to remember more and better, but we need to train our brains.

Also, CrowdScience heads to Cambridge University where Marnie Chesterton lands herself in a study. The scientists scan her brain while she exercises her memory muscles and we discover why sometimes memories get muddled up.

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Marnie Chesterton Producer: Louisa Field

(Image: Woman scratching head, thinking brain melting into lines. Credit: Getty Images)

People often talk about being descended from apes. But go back a bit further and we have a more unlikely ancestor – fish. Improbable as it may sound, the creature that gave rise to every bird, reptile and mammal on Earth today lived a fully aquatic life.

So how did it switch to life on land? And how hard was it to swap swimming for walking and breathing fresh air? That’s what CrowdScience listener Pierre in France wants to know, and what Marnie Chesterton is in Scotland to find out. She goes fossil hunting with members of the TW:eed Project team, as they try to uncover remains of creatures that are crucial in helping solve the puzzle of terrestrial life. She also discovers the landscape these early ancestors walked into – an alien and relatively empty world completely different to what we see today - where grass and flowers were yet to evolve.

But not everything in this story is preserved in rock. Marnie goes to see a living relic of this period of evolution, and finds out what it can tell us about possibly the most important event in the history of our species.

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Marnie Chesterton Producer: Anna Lacey

(Image: Artists impression of underwater environment of Carboniferous swamp depicting a rhizodont; a large predatory fish. Credit: Mark Witton)

Unpleasant man-made noise is something that disturbs many of us and even damages our health. But as millions more people move into crowded cities around the world, it's a cacophony that we almost unavoidably create ourselves. CrowdScience listener Diana from New York City in the USA got in touch to ask how we can temper the din and live a more peaceful life. Presenter Anand Jagatia heads to an acoustics lab at the University of Salford in Manchester, UK, to meet the researchers and engineers investigating the best ways to make cities more pleasant for our ears whilst still maintaining the ‘buzz’ of city life. And reporter Chhavi Sachdev takes us to Mumbai in India, where we discover how sound mapping is being deployed on the city’s streets as the first step to improve the life and health of its citizens.

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Anand Jagatia Producer: Jen Whyntie

(Image: Children cover their ears as the truck convoy front passes. Credit: Getty Images)

Is there any scientific proof of an afterlife? Six months ago, CrowdScience tackled a question from a listener who wanted to know whether there was life after death. But following more listener emails, presenter Marnie Chesterton returns to the subject to investigate the world of ghosts, souls and parapsychology. She meets Professor Susan Blackmore, who studies out-of-body experiences and has spent decades hunting for scientific proof of life after death. And she visits the woman who, despite dying in the 1950s, is alive and thriving on a cellular level and helping scientists find cures for cancer, Parkinson’s and other diseases, in laboratories across the world…

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Produced and Presented by Marnie Chesterton

We test the science behind parasitic therapy to answer listener Michael’s question about whether intestinal worms can help us stay healthy, and visit a deworming programme in a rural Ugandan village.

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Marnie Chesterton Producer: Marijke Peters

(Picture: Tapeworm in human intestine, Credit: selvanegra/Getty Images)

Carbon dioxide levels in our atmosphere today are higher than at any point in human existence. But going back further into Earth’s history, when do we find concentrations as high as they are now - and what was the planet like back then?

CrowdScience sets out to answer our listener Thomas’s question, travelling back through time with the help of Antarctic ice cores, ancient plant fossils, and microscopic popcorn-shaped organisms called foraminifera, all of which hold clues to past climates.

Enlisting the help of chemists, botanists and palaeontologists, we find out about the huge swings in atmospheric carbon dioxide from prehistoric times to the present day, and ask the all-important question: can this help us understand what's happening to our climate now?

Do you have a question we can turn into a programme? Email us at crowdscience@bbc.co.uk

Presenter: Marnie Chesterton Producer: Cathy Edwards

(Image: Polar bear on an ice floe. Credit: Getty Images)