CrowdScience

Listener Avalon from Australia wants to know why people use conspiracy theories to explain shocking events. Are we more likely to believe conspiracy theories in times of adversity? What purpose do conspiracy theories serve in society? Marnie Chesterton speaks to the scientists to explain their popularity, even in the face of seemingly irrefutable evidence. Presented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service.Image: All-seeing eye of God inside triangle pyramid. Credit: paseven, Getty Images

These days we’re more acquainted with soap than ever before, as we lather up to help stop the spread of coronavirus. And for CrowdScience listener Sharon, this set off a steady stream of soapy questions: how does soap actually work? How was it discovered in the first place, long before anyone knew anything about germs? Are different things used for washing around the world, and are some soaps better than others? We set up a CrowdScience home laboratory to explore the soap making process with advice from science-based beauty blogger Dr Michelle Wong, and find out what it is about soap’s chemistry that gives it its germ-fighting superpowers. Soap has been around for at least 4000 years; we compare ancient soap making to modern methods, and hear about some of the soap alternatives used around the world, like the soap berries of India.And as for the question of whether some soaps are better than others? We discover why antibacterial soaps aren’t necessarily a good idea, and why putting a toy inside a bar of soap might be more important than tweaking its ingredients.Presented by Marnie Chesterton. Produced by Cathy Edwards for the BBC World Service.Image: Child with thoroughly washed hands. Credit: Getty Images.

Think of the oceans and an empty and peaceful expanse relatively untouched by humankind might come to mind. But is this peace an illusion? CrowdScience listener Dani wants to know if the noise of shipping and other human activity on the oceans is impacting on sea life.To find out, Marnie Chesterton takes a deep dive to learn how marine animals have evolved to use sound; from navigating their environments to finding a mate or hiding from prey. She then speaks to a scientist who is using acoustic observatories to track the many ways human activity - like sonar and shipping - can interfere.Marnie virtually visits a German lab which tests the ears of beached whales, dolphins and seals from around the world to try and ascertain whether they suffered hearing damage, and what might have caused it. What other smaller creatures are negatively impacted by underwater noise? Marnie learns that acoustic trauma is more widespread than first thought.As human life continues to expand along ocean waters, what is being done to reduce the impact of sound? Marnie meets some of the designers at the forefront of naval architecture to see how ship design, from propellers to air bubbles and even wind powered vessels can contribute to reducing the racket in the oceans.Presented by Marnie Chesterton. Produced by Melanie Brown for the BBC World Service.Main Image: The front of a humpback whale underneath the sea in Shetland Islands, Scotland, December 2016. Credit: Richard Shucksmith / Barcroft Im / Barcroft Media via Getty Images

Worms are not the cutest of creatures. They’re slimy, often associated with death and tend to bring on feelings of disgust in many of us. But listener Dinesh thinks they’re underrated and wants to know whether earthworms could be the key to our planet’s future agricultural success? He’s an organic farmer in India’s Tamil Nadu province who grows these annelids to add to the soil, and he wants Crowdscience to find out exactly what they’re doing. Anand Jagatia dons his gardening gloves and digs the dirt on these remarkable creatures, discovering how they can help improve soil quality, prevent fields from becoming waterlogged, and improve microbial numbers, all of which has the potential to increase crop yield.But he also investigates the so-called ‘earthworm dilemma’ and the idea that in some parts of the world, boreal forest worms are releasing carbon back into the atmosphere, which could have dangerous consequences for climate change.(Photo:

Shoes are a surprisingly recent human invention. But running isn’t. That means for most of our time on the planet, we’ve run barefoot. Today, in most countries it’s rare to see people out in public without shoes, let alone running. But might our aversion to the free foot be causing us pain?CrowdScience mega-fan Hnin is an experienced runner, she enjoys ultra-marathons back home in Australia. But about six months ago she developed extreme foot pain, the condition ‘Plantar Fasciitis’, and this has meant she had to stop doing what she loves. She reached out to CrowdScience presenter Chhavi Sachdev, to find out if barefoot running could reduce her pain and improve her performance. Simply put, is barefoot running better? In an attempt to find Hnin some answers, Chhavi hits the ground… running. Literally throwing off her own shoes on the streets of her home city of Mumbai, India, to see how feeling the ground can change her whole gait. And with Prof. Dan Lieberman, Chhavi learns what sets the human runner apart from other species while uncovering the strange form our feet have. She speaks with the Dr Peter Francis, a researcher whose life’s work has focused on curing the pain in his own feet and learning how to help others. But performance is also important for runners. Biomechanics and shoe expert Dr Sharon Dixon explains how modifications to the sports-shoe are helping marathon runners set records, and blade-running athlete Kiran Kanojia shows Chhavi how the technology behind her two prosthetic legs let her emulate either natural walking or natural running. Presented by Chhavi Sachdev Produced by Rory Galloway (Photo: barefoot running on beach. Credit: Getty Images)

If you put one person’s blood into another person , sometimes it’s fine and sometimes it’s a death sentence. French physician Jean-Baptiste Denis discovered this when he performed the first blood transfusion back in 1667. He put the blood of a lamb into a 15-year boy. The teenager survived but Denis’s third attempt killed the patient and led to a murder charge.In 1900, Austrian doctor Karl Landsteiner discovered the reason for this lottery – blood types. The red blood cells in our bodies are decorated with different marker molecules called antigens. These define us as A, B, AB or O blood type. And this is just one of 38 different systems for classifying our blood. CrowdScience listeners have discovered that we aren’t the only animal with blood types and want to know more. Dogs have 12 different blood groups, so how do they cope when they need a transfusion? CrowdScience meets some very good dogs who donate a pint to the pet blood bank in return for a toy and a treat. Each pint saving up to 4 other dogs’ lives. We also hear how examining our blood types can tell us more about our links to our ape-like cousins and how the human species spread around the world. And what about the future of blood types – can we use science, and animal blood to get around the problems of transfusions?Producer and Presenter: Marnie Chesterton Photo: Red Blood Cells. Credit: Getty Images

What exactly it means to be conscious has long been a question of profound debate amongst philosophers, and more recently, scientists. There are no easy answers, and it gets even trickier when you start asking whether animals are conscious: how can you find out about their subjective experience when they can’t tell you about it?Never afraid to tackle the impossible, CrowdScience is looking for answers after listener Natalie got in touch. She has lived with her cat for years and has a strong sense that he has thoughts and feelings: he has his own personality, acts in complex ways, and even has ‘grumpy days’. But is this consciousness? Is there any way of scientifically testing for it? How different from our own inner world is that of a cat, an octopus, or a bumblebee? And if we can find any answers to these puzzling questions, how does that affect the way we treat animals - not just our pets, but all the animals we share our planet with?We meet Natalie and her cat, and discover how scientists have explored the minds of pigs, cows and cuttlefish. Helping us ponder the elusive question of animal consciousness are philosopher Peter Godfrey-Smith, neuroscientist Anil Seth, animal welfare expert Donald Broom, ethicist Jessica Pierce, and comparative psychologist Alex Schnell.Featuring David Seddon as the voice of Chicco the Cat.Presented by Anand Jagatia and Produced by Cathy Edwards for BBC World Service.(Photo: Black Cat. Credit: Getty Images)

We were bowled over by a question from one CrowdScience listener in Australia wants to know how likely it is that the atoms in his body have been used in someone else’s body? We all like to think we are unique; no one is quite like us. But is that really true?Presenter Marnie Chesterton tackles Moshe’s question with help from every area of science. From geologists helping us work out how many atoms are on the Earth’s surface to biologists helping us work out how many atoms each body uses. Perhaps we are much less special than we think.Presented by Marnie Chesterton. Produced by Caroline Steel for the BBC World Service. (Photo:

Have you ever broken up a fight? Or pushed someone out the way of an oncoming vehicle, only to be hit by it yourself? Most of us probably haven’t taken as many risks as listener Alix, who has put herself in peril to save strangers on several occasions, and she wants Crowdscience to investigate why. At a time when medical professionals have to weigh up the personal dangers of working on the frontline of the Coronavirus crisis, it’s a particularly timely question. Marnie Chesterton finds out why it’s a good thing that children push the boundaries of what’s safe during playtime, because it makes them less anxious adults. And she questions the existence of the so-called bystander effect, discovering how evolution has ensured we’re a much braver species than we sometimes give ourselves credit for. But she hears from some social scientists who say there’s no such thing as a ‘hero’, however likely they are to intervene to help others.The virtual reality experience in this programme was created by the Human-Computer Interaction Lab of the University of Udine, ItalyThis programme has been updated since its original publication to correct an editorial error.Presented by Marnie Chesterton Produced by Marijke Peters

This week the kids take over. Our younger listeners are as curious as their parents, it seems, so presenter Marnie Chesterton seeks out the finest minds and attempts to answer a raft of their science questions, including why can’t you tickle yourself? Why don’t our eyebrows grow as long as the hair on our heads? Not content with humankind, these whizz kids have been pondering deeply about other animals. Ava, 9, from the UK wants to know if any other animals kill for fun, like some humans do. Not limited by planet Earth, these little thinkers have been contemplating even weightier questions. Joshua, 13, from Kenya wonders if our Solar System rotates around anything. And Seattle-based Michael, 10, puzzles over what would happen if a black hole collided with a wormhole. These and other mysteries are uncovered by Marnie and her experts. Presenters: Marnie Chesterton & Arlo Byrne Producer: Dom Byrne[Photo: Children Tickling each other, Adorable laughter. Credit: Getty Images]

There are over 7000 living languages on earth today. These mutually unintelligible means of communication are closely associated with different groups' identities. But how does a new language start out? That’s what listener BK wants to know. BK lives on one of the islands of the Philippines, where he speaks three languages fluently and has noticed there is a different language on almost every island. Presenter Anand Jagatia finds language experts from around the world who tell him about the many different ways that languages can form. Professor Dan Everett explains that languages naturally change over centuries to the point they are mutually unintelligible, and Quentin Everett describes how his research has identified striking similarities between biological, and linguistic evolution. Sally Thomason, Professor of linguistics in the USA tells us about the more unusual ways that languages can form through contact, or purposeful distancing measures, and Anand speaks with a producer of the BBC’s Pidgin service, about how the contact language nigerian pidgin may be developing into an official language West Africa. Finally, the inventor of a constructed language from the movie Avatar, tells CrowdScience what he has learned about language by creating the fully functional Na’vi language from scratch, and what Na’vi’s adoption by speakers around the world can tell us about the importance of language for creating community. Hearing from different languages from around the world through the programme, CrowdScience get to grips with the many ways new languages can form. Presented by Anand Jagatia, Produced by Rory Galloway (Photo: Chalk board of languages, Credit: Getty Images)

Despite being a universal need, talking about our toilet use and the infrastructure that aids us remains somewhat taboo. Whilst sectors like telecommunications and computing have undergone rapid transformations over the past century, the flush toilet and wastewater system have mostly remained unchanged. CrowdScience listeners Linda and Allison wonder if flush toilets – and the clean water used to wash waste away - make economic or environmental sense. So CrowdScience presenter Marnie Chesterton looks under the toilet lid, to probe (in a sanitary fashion) whether our sewerage systems and plumbed toilets are fit for purpose. In a future where population growth and climate change are likely to affect water demands, can we continue to use clean water to dispose of our waste and should the developing world be emulating this model?Around 2 billion people don’t have access to proper toilets or latrines, risking serious health consequences. Marnie investigates how countries without comprehensive sewerage infrastructure deal with human waste and how science is providing novel ways to dispose of - and use – human waste. Marnie speaks to a Kenyan scientist using poo-eating fly larvae to process faeces and a North American scientist who is developing a smart-toilet she hopes will monitor our health through sampling our daily movements. Are we ready to break taboos to innovate our toilet habits?Presenter: Marnie Chesterton Producer: Melanie Brown(Image: Man looking at toilet. Credit: Getty Images)

What is the smallest particle of matter? How does radiation affect our bodies? And, how is particle physics useful in our everyday lives?CrowdScience takes on particle physics questions from listeners all over the world. Marnie Chesterton and Anand Jagatia get help from particle physicists from the Large Hadron Collider at CERN and medical physicist Heather Williams. Presented by Marnie Chesterton and Anand Jagatia Produced by Cathy Edwards, Jen Whyntie and Louisa Field (Photo: Particle collider, Credit: Getty IMages)

What’s the importance of zero, and how was it discovered? How do scientists calculate Pi’s infinite digits? Why do so many people find maths difficult – and what’s the most difficult thing in maths?CrowdScience takes on a whole bunch of questions sent in by high school students in Spain. Like many children all over the world, their school is currently closed due to the coronavirus lockdown, but lessons continue at home. So how are their studies going, and can CrowdScience help out?We attempt to answer some of their trickiest maths questions, with the help of mathematicians Katie Steckles and Matt Parker, and mathematical biologist Kit Yates.Presenter: Marnie Chesterton. Producer: Cathy Edwards (Photo: A boy studying. Credit: Getty Images)

If you're an exercise fan, you'll know that sweating is how our bodies keep us cool, but how much water we lose and which bits of us get wettest depend on a whole host of factors. Jamaican listener Andre wants to know why he sweats in a heart-shape when he hits the gym, and we find out how everything from the clothes he wears to the moves he's doing explain his unusual perspiration patterns. In Kenya we meet a woman whose permanently clammy hands cause her to drop her mobile phone, and sweaty feet start to stink when she spends too long in shoes. Hyperhidrosis is a condition affecting millions of people worldwide but an expert explains some of the treatments for this mysterious condition. Presenter: Marnie Chesterton Producer: Marijke PetersImage Credit: Getty Images

If you have ever watched a spider as it works to build a web, spiralling inwards with a thread of silk, that intersects each glistening spoke with a precise touch of the foot, you will know that it is a remarkably complex behaviour. In this episode, presenter Geoff Marsh dives into the minds of spider-constructors as they build their webs. CrowdScience listener Daan asked us to find out how spiders can build webs without ever being taught how to do it. Are they just little robots controlled entirely by their genetic instructions? Spider silk expert Dr Beth Mortimer, describes the process of building a web in detail, while Professor Iain Couzin explains the simple modular behaviours that build up, in sequence, to create apparently complex instincts, like the huge locust swarms that are sweeping across vast areas of Africa and Arabia. Taking us deep under the exoskeletons of invertebrates, Professor Gene Robinson reveals an animal's behaviours can be altered by their genes, and the root similarity between learning and instincts. Spiders, despite their tiny size, have fascinating behaviours. Some jumping spiders can work out the best way out of a maze, and one arachnologist reveals how some social spiders can cooperate to build communal webs and capture moths that are many times their size. Geoff searches for the science that can reveal how instinct can create complex behaviour by setting up interviews at the homes of spider experts from around the world. Presented by Geoff Marsh. Produced by Rory Galloway for BBC World Service.Image: European garden spider, Araneus diadematus hanging in the web. Photo by: Michael Siluk / Universal Images Group via Getty Images

Listener Keith from Lincolnshire wants to know how to reduce stress as he is under extreme pressure as a firefighter. Not only does he have to cope with the stress of responding to emergency situations but he has to do it while wearing challenging breathing equipment.We all experience times of stress, especially given the current situation, our chest starts to feel tight and our breathing becomes shallow. Claudia Hammond – presenter of BBC World Service programme Health Check – explains steps we can take to protect our mental health during this pandemic.How should we alter our breathing to manage stress? Presenter Anand Jagatia speaks to breathing experts to find techniques to help listener Keith, and everyone else.Presented by Anand Jagatia. Produced by Caroline Steel for BBC World Service.

In medicine, it’s long been recognised that a placebo, a sham medicine or treatment, can have a powerful positive effect on a patient’s health. Part of that effect relies on a person’s belief that an inactive substance or treatment (for example, a sugar pill) is in fact an active drug. Placebos come in many forms, and the scientific study of placebo is an active area of research. With this in mind, CrowdScience listener Nigel got in touch to ask if can placebos be used to improve sports performance. As an amateur sports enthusiast, he’s been reading up on his sports psychology to try and improve his game, but he wonders if any coaches or psychologists use placebos to improve performance? Always ready to take up a challenge, presenter Anand Jagatia explores the world of endurance sport to find out how a placebo might used to improve athletes’ performances, as well as his own, and look at how advances in brain science are helping us understand the unusual neurobiology of placebo. And what of the amateur golfer, or rugby or table tennis player - can a placebo help? On an individual level, so called ‘verbal placebo’ is a technique that can help players with anxiety, confidence and concentration, and ultimately make them win more. And what about team sports? When, say, a new manager takes over at an ailing football club, and sparks a massive reversal in poor results, is that a placebo effect in action? The CrowdScience team investigates.Produced by Dom Byrne, presented by Anand Jagatia.

If you've ever felt the urge to shop till you drop, then you may already know about some of the clever ways retailers convince us to consume. From flash sales to so-called unbelievable offers, there are a whole range of techniques aimed at encouraging us to flash the cash. Listener Mo works in marketing, so knows more than most about the tricks of the trade - but he wants CrowdScience to investigate how neuroscience is being used to measure our behaviour and predict what we’ll buy. Marnie Chesterton finds out how brain scans are being used to discover which specific aspect of an advertisement a person is responding to, and then she hears how this information is being used by companies who want to sell us more stuff. But there's also evidence to suggest we have less control over these decisions than we think, and that computers are getting closer to detecting our intention before we're even aware of it ourselves. And this could have huge implications for the way we shop.Presented by: Marnie Chesterton Produced by: Marijke Peters(Photo:

Many of us are fascinated by our ancestry: knowing where our families came from can give us a sense of identity and roots. Tracing your family tree is a time-honoured tradition, but several companies now sell DNA tests that offer you insights into your heritage: so you might find out you’re 70% Nigerian, 39% Italian, or 11% South Asian, for example.There’s no doubt that genes contain clues about your family history, but how reliable are these commercial tests? That’s what CrowdScience listener Karen wondered after an update of her test results showed her going from 39% Scandinavian to 2% Norwegian. How confident can she be in her results now? And what does it actually mean to be 2% Norwegian, in terms of your family tree?Presenter Alex Lathbridge delves into his own African and European ancestry, talks to some of the companies offering these tests, and unpicks the complex relationship between genetic science and family trees. We meet a woman who found her long-lost uncle with a combination of a DNA test and old-fashioned archive research; and look to the Americas to ask whether genetic testing can restore ancestral ties erased by the inhumanity of the transatlantic slave trade. Presented by Alex Lathbridge Produced by Cathy Edwards for the BBC World Service(Photo: Elderly hands looking at old photos of self and family. Credit: Getty Images)

Since the outbreak of a new strain of coronavirus late last year, health workers and governments have been rushing to limit transmission by deploying containment tactics and anti-contamination campaigns. But, as the virus spreads around the world, what are scientists doing to help our bodies fight off or resist this new infectious disease? Viruses that cause human disease can be notoriously tricky to tackle. They don’t respond to antibiotics, can spread rapidly between human hosts, and even evolve improved ways of working as they multiply. Presenter Marnie Chesterton heads to the University of Oxford’s Nuffield Department of Medicine to meet the researchers who are urgently searching for solutions. Professor Tao Dong is Director of Chinese Academy of Medical Sciences Oxford Institute, collaborating with colleagues on the ground in China to see how Chinese patients’ immune systems are responding to the virus, which could inform vaccine design. Professor Sarah Gilbert leads the Jenner Institute’s influenza vaccine and emerging pathogens programme. She’s been developing a vaccine against another strain of coronavirus that caused the Middle East Respiratory Syndrome (MERS) outbreak, and is using the same technology to generate a new vaccine against the 2019 coronavirus. And, whilst that’s being developed, there is a possibility that some existing antiviral drugs may even help infected patients – Professor Peter Horby is working with colleagues in China on clinical trials to see what might work. CrowdScience goes into the laboratories using cutting edge science to combat coronavirus. Presented by Marnie Chesterton Produced by Jen Whyntie for the BBC World Service(Photo: Coronavirus Credit: Getty Images)

Jump on-board a doomed mission to the Moon. Apollo 13: the extraordinary story, told by the people who flew it and saved it. Search for 13 Minutes to the Moon wherever you get your podcasts. #13MinutestotheMoon

Why are we obsessed with crime? Kay from Hamburg, Germany asks as every Sunday evening Germans pile into their local pubs to watch Tatort, a hugely successful crime drama which has been running for 50 years. Presenter Marnie Chesterton starts with the science and speaks with psychologists to get to the bottom of where this obsession might come from. Have we evolved to have an innate obsession with danger or are we addicted to feeling fear?Or perhaps the dramatisation of crime fuels our obsession. Producer Caroline Steel visits the film set of BBC crime drama, Line of Duty. Producer Jed Mercurio explains what draws us to crime narratives and the techniques he uses to keep his audience captivated. But does the way we chose to represent crime in media match up with reality? And what is the impact of this on society and policy?(Photo: body outline. Credit: Getty Images)

Weather: wet, dry, cold, hot, sunny, windy or downright weird - there’s nothing quite like it as a conversation starter, from Austin to Jakarta. And judging from the large volume of emails about all things meteorological in the CrowdScience inbox, there’s plenty to talk about. What’s the weirdest weather on Earth, and how big a chance is there of it happening? Why does it always seem to rain on the days when we’re not working? And – conversely – is there any way we could make it rain when and where we need it to? Presenter Anand Jagatia finds out the answers to these questions and more by bringing together a panel of experts under the CrowdScience umbrella: Prof Liz Bentley, Royal Meteorological Society; Dr Anthony Rea, World Meteorological Organization, and Dr Rebecca Buccholz, National Centre for Atmospheric Research. Presented by Anand Jagatia. Produced by Jen Whyntie for the BBC World Service (Photo: Lenticular Cloud. Credit: Getty Images)

A lovely day out in the countryside can be blighted when swarms of midges or mosquitos invite themselves to the party. A CrowdScience listener in New Zealand has noticed that, when sand-flies come a-biting, she and her daughter are targeted, while her husband and other daughter escape unharmed. She wants to know why some, but not all of her family become bait for insect bites. CrowdScience delves into a world of smells, called semiochemistry, which explores the aromas one animal uses to attract or repel another. Does our attractiveness as a blood meal to insects come down to what we wear, what we’ve eaten or is it all in our genes? Host Marnie Chesterton discards the DEET and bravely offers herself up as a meal for mozzies, in a quest for answers.(Photo:Mosquito on skin. Credit: Getty Images)

Cancer is the second leading cause of death in the world. Many of us will at some point in our lives be confronted with the disease – either by falling ill ourselves or through a family member or friend. For CrowdScience presenter Marnie Chesterton, the diagnosis would change her life. The range of cancer symptoms and mortality rates vary considerably. Not all cancers are fatal and in some cases, cancer ends up more like a chronic debilitating disease, resulting in patients eventually dying from some other condition. This has got listener Gill in Scotland wondering – why do we call all cancers, cancer? And when did doctors first realise that all cancers are part of the same problem? First described by the Egyptians thousands of years ago and later coined by the Greek physician Hippocrates as “karninos”, the Greek word for “crab”, cancer is ominously absent from medical literature until the late 19th century. Throughout history it has puzzled, infuriated and enticed doctors and scientists to push medical science to its breaking point. Archaeologists have recently discovered that the ancient Egyptians had a term for cancer and that remedies they used then contain compounds that are found in modern chemotherapy. As we uncover the science and history of cancer, presenter Marnie Chesterton takes us on a journey through her own experience of living with and beyond the diagnosis and we examine the promise of future treatments. Presented by Marnie Chesterton. Produced by Louisa Field. [Photo: Cancer Cell. Credit: Getty Images]

Today, once-fatal diseases like the plague, sepsis, or cholera can be treated simply and quickly with a pill. These tiny tablets hold compounds that can fix illnesses, and most people don’t think twice about taking an asparin for a headache. Modern medicine looks nothing like the plants that many of them are derived from. But there must have been a moment, when the first humans decided that a particular plant, fungus, or mineral might cure them of an upset stomach, or infected wound. Right? That’s what listener Andrew Chen wondered, so he emailed CrowdScience to find answers.Presenter Anand Jagatia speaks with an archaeologist, a botanist, an ethno-pharmacologist, a zoologist and a historian to uncover the story of early human experimentation with ‘drugs’ from plants, fungi, animals and minerals. The history of humans is full of illness and poor health, and it seems we’ve always tried to fix this. Anand discovers the connection between food and medicine while making tonic water from scratch with Kim Walker at the Royal Botanic Gardens of Kew, and tastes the daisy-like Chinese herb that was first used thousands of years ago, and then – once tested - became one of the best modern drugs for treating the world’s most deadly infectious disease. Listener Andrew’s inspiration came from a previous episode of CrowdScience ‘Who were the first farmers?’ and so we return to expert anthropologist Cheryl Makerewicz who tells us about the ecological knowledge of hunter-gatherers and pastoralist communities. With Jaap de Roode, Anand discovers that conscious thought isn’t a pre-requisite of medical discovery, and historian Vivienne Lo explains how written word helped to standardise generations of medical knowledge in East Asia. Previously medical knowledge had been irrevocably linked with shamanism, magic and spirituality, but with modern medicine this changed – but today there is still much we can learn from ancient forms of knowledge, Christophe Wiart explains how his science focuses of discovering what plants tribal people in east Asia have used for centuries to cure their ailments. These early methods may help us combat new diseases today. Presented by Anand Jagatia Produced by Rory Galloway [Photo: Women using plant medicines. Credit: Getty Images]

CrowdScience heads to Freetown, Sierra Leone for a panel debate in front of a live audience to answer listener questions about how artificial intelligence is helping tackle some of the world’s most pressing issues. Anand Jagatia is joined by regional science experts to explore how robots, drones and big data are transforming sectors such as agriculture, health and governance. Could clever machines help eradicate invasive species? Will block chain IDs eventually replace physical documents? And while this technology is heralded as a force for change we’ll ask whether fears of an AI takeover are unfounded?Presented by Anand Jagatia and Produced by Marijke Peters and Mel Brown(Photo: The panel and Audience at Crowd Science live event in Sierra Leone. Credit: BBC)

Super-sized volcanic eruptions and giant asteroids crashing in from outer space are the stuff of disaster movies. They have listener Santosh from South Africa slightly concerned. He’d like to know what’s being done in real life to prepare for this kind of event. Although the chance of these events occurring is low, Santosh isn’t entirely wrong to be worried: Earth has a much longer history than humans do, and there’s evidence that several past extinction events millions of years ago wiped out the dominant species on the planet at the time, as we’ve heard before on CrowdScience. The kind of extraordinary geological and extra-terrestrial hazards thought to be responsible for the death of millions of lives do still exist. So is there really any way that humans could survive where the dinosaurs – and plenty of other species – have failed? Presenter Marnie Chesterton finds out by meeting experts who are already preparing for the remote but real possibility of the biggest disaster we could face. It turns out that in real life most things we can think of which could cause an extinction event are being watched closely by scientists and governmental agencies. How worried we should really be by the possibility of a sudden super-volcanic eruption at Yellowstone in the USA, or one of the other enormous volcanoes dotting our planet’s surface? Marnie heads into an underground bunker near the remote Scottish coast to find out if hiding out is a viable survival option. Now a museum, Scotland’s Secret Bunker, formerly RAF Troywood, is one of a network of nuclear shelters built by nation states during the Cold War. And she hears about one of the combined space agencies most ambitious projects yet: NASA and ESA’s Asteroid Impact and Deflection Assessment mission to crash an impactor into an asteroid’s moon to find out whether we could knock any potentially problematic collisions off-course well before Earth impact.Produced by Jennifer Whyntie for BBC World Service(Photo: Post apocalypse sole survivor. Credit: Getty Images)

Is there something bigger than infinity? Does quantum mechanics affect how I think? And why can I suddenly do algebra? As ever, we’re not afraid to tackle the big questions on CrowdScience. After a previous episode about the relationship between mathematics and reality, we received a flood of profound and difficult questions, so we dive back into the world of maths, physics and philosophy to try and answer them. A panel of experts help us puzzle out whether some infinities are bigger than others - and why that matters, as well as what quantum mechanics can teach us about the workings of the brain. And we seek answers for one of our listeners who surprised himself by being able to figure out mathematics equations he previously found unfathomable. With philosopher of physics Dr Eleanor Knox, mathematician Dr Katie Steckles, and Dr Aldo Faisal, an expert in neurotechnology.Presented by Marnie Chesterton Produced by Cathy Edwards for the BBC World ServicePhoto:

Reducing climate change and global warming is one of the biggest and most urgent challenges for everyone as we enter a new decade. The CrowdScience team have been trying to figure out how to play our part in reducing our carbon footprint. So what’s the best way forward? Presenter Marnie Chesterton starts to find out by pitting three of her colleagues against each other for the first phase of our challenge. Anand Jagatia, Geoff Marsh and Melanie Brown have all been tasked with answering a listener’s question in the lowest-carbon way possible. Along the way, they must monitor and account for every emission – from their travel methods to their choice of sustenance whilst working. It turns out that the challenge is not only in acknowledging all the types of activity that produce emissions, but in working out the volume of greenhouse gases produced. Marnie judges her colleagues’ efforts, determines a winner, and dispatches the losing challenger to look further into carbon calculation, and to find out about the possibilities of legitimately offsetting the overall footprint. And we start our on-going experiment using a broadcast industry carbon calculator to find out the most carbon-efficient and sustainable ways to keep answering everyone’s questions and sharing more cutting-edge global science. Presented by Marnie Chesterton Produced by Jen Whyntie for the BBC World Service(Photo:

Two years ago reporter Anand Jagatia travelled up beyond the Arctic Circle to meet Norwegian researchers in order to answer a question from US listener Kira on why some people function best in the mornings whilst others only come alive at night. In this episode we revisit the topic with the help of science writer and Parentland podcast presenter Linda Geddes, author of Chasing the Sun, a book which explores the science behind the sun’s effects on our bodies and our minds.The morning sun helps to kick-start our day and our body’s biological cycle – so what happens when it barely rises above the horizon or we live for prolonged periods in artificial environments where the sun never shines? Research has suggested that some communities in northern latitudes are better protected against the mental and physical effects of reduced exposure to sunlight in the winter which might have implications for those suffering the winter blues. Presenter Anand Jagatia, Producer: Rami Tzabar(Photo: Woman basking in the sun. Credit: Getty Images)

What is empathy? This week’s question comes from Maria in Amsterdam who has noticed that when one of her friends is in pain, she feels their pain too, literally. Maria wants to know - is she experiencing a type of ‘super’ empathy? To help find the answer, Marnie Chesterton visits the Netherlands Institute for Neuroscience and gets into an MRI scanner to discover what is happening in her brain when she empathises. She talks with a pro-social psychopath to find out how psychopaths experience empathy differently and how they navigate social situations.And Marnie meets with a mediator specialising in The Israeli–Palestinian conflict, to learn the value of empathy when the stakes are at their highest. (Photo: Back view of loving Mum hug teen daughter. Credit: Getty Images)

As CrowdScience celebrates its third birthday, the team takes time to revisit some of our early episodes, and catch up with listeners to discover if the answers we uncovered changed the course of their lives? We hear from Zach, who has learned to let go of a possibly lost memory and Erin, who discovered technology could hold the key to finding the man of her dreams. And two years after he emailed to ask why he couldn’t kick his habit, we ash Sharif whether he has finally managed to stop smoking? (Photo: Man listening to podcast. Credit: Getty Images)

Buzzing insects that sting and fall into your food can be annoying. But perhaps we should think twice before taking aim with the fly swatter because bug populations around the world are in rapid decline. This worries CrowdScience listener Daria; she wants to know what will happen to our food production without the help from our tiny friends – the pollinators? And what can she do, as a city-dweller, to help the bugs?The dollar value of agricultural services that insects supply – for free – is estimated to be 350 billion dollars worldwide. For scientists, a major challenge is the lack of long-term studies of insects on a global scale – in fact – entomologists worry that species are dying out faster than we can document their existence. The culprits, they believe, are climate change, invasive species, land-use and pesticides. CrowdScience speaks to the scientists who want to save the bugs; one project capitalises on the chemical signals that attract certain species of pollinators while others are building ‘bee hotels’ to encourage native bees back into our cities. Presenter: Marnie Chesterton Produced by Louisa Field for BBC World Service. (Photo: Hoverfly on Yellow Dandelion Flower. Credit: Getty Images)

66 million years ago, a huge asteroid hit the earth, wiping out most of the dinosaurs that roamed the land. It would still be tens of millions of years before the first humans appeared - but what if those dinosaurs hadn’t died out? Would we ever have evolved?CrowdScience listener Sunil was struck by this thought as he passed a Jurassic fossil site: if dinosaurs were still around, would I be here now? We dive back into the past to see how our distant mammal ancestors managed to live alongside huge, fierce dinosaurs; and why the disappearance of those dinosaurs was great news for mammals. They invaded the spaces left behind, biodiversity flourished, and that led – eventually – to humans evolving. It looks like our existence depends on that big dinosaur extinction. But we explore a big ‘what if?’: if the asteroid hadn’t hit, could our primate ancestors still have found a niche – somewhere, somehow - to evolve into humans? Or would evolution have taken a radically different path: would dinosaurs have developed human levels of intelligence? Is highly intelligent life inevitable, if you give it long enough to develop? We look to modern day birds - descendants of certain small dinosaurs who survived the asteroid strike - to glean some clues.With artist Memo Kosemen, palaeontologists Elsa Panciroli and Darren Naish, palaeobiologist Anjali Goswami, and Professor of Comparative Cognition Nicola ClaytonPresented by Marnie Chesterton and Anand Jagatia Produced by Cathy Edwards for the BBC World Service(Photo: Silhouette of people and Dino. Credit: Getty Images)

Science fiction is full of people settling on distant planets. But even the closest stars would take millennia to reach with current speeds of travel, by the time any passengers reached an extra solar planet, they would be long dead. So CrowdScience listener Balaji asked us to find out whether humans could hibernate for interstellar travel?To uncover the science fact behind this idea, Anand Jagatia holds a tiny hibernating dormouse at the Wildwood Trust in Kent, and meets Dr Samuel Tisherman who puts his patients into suspended animation for a couple of hours, to save their lives after traumatic injuries that cause cardiac arrest. We ask if Dr Tisherman’s research could be extended to put healthy individuals to sleep for much longer periods of time? It’s a question that neuroscientist, Professor Kelly Drew is studying, in Alaska Fairbanks. She uses Ground Squirrels as a model to understand internal thermostats, and how hibernating mammals manage to reduce their core temperatures to -3 degrees Celsius. Anand speculates wildly with science fiction authors Adrian Tchaikovsky and Temi Oh whose characters in their books ‘Children of Time’ and ‘Do You Dream of Terra Two?’ traverse enormous distances between habitable planets. But is human stasis something that would actually be useful? John Bradford is the director of SpaceWorks, this company works with NASA to try to investigate human hibernation for space travel. He’s trying to make space-based human hibernation a reality, and it seems that may be closer than you’d think. Presented by Anand Jagatia Produced by Rory Galloway(Photo: People in hibernation. Credit: Getty Images)

Australian listener Lizzy is trying to reduce her footprint on this planet and is particularly interested in palm oil. It is everywhere - in shampoo, lipstick and face cream and even food stuffs like biscuits and spreads. In fact, WWF say it is used in 50% of all supermarket products so it's something most of us will come into contact with every day.Lizzy wants to know whether she should stop eating it. Because on the one hand, she sees emotive adverts depicting dying orangutans, deforestation and burning peatlands, releasing vast amounts of climate changing gases like carbon dioxide. On the other, she has read that palm oil is the most productive of the vegetable oils, using far less land than others. So would boycotting palm oil displace the problem elsewhere, she wonders? Would buying sustainable palm oil be best? Partnering up with with another BBC World Service programme, The Food Chain, presenter Graihagh Jackson heads to one of the biggest producers of palm oil: Malaysia. She visits small holder plantations, who collectively provide 40% of the world’s palm oil, to find out how palm oil is grown and to ask them about their perspective on a product that provides them with their livelihood. What would incentivise them to engage in greener practices? And what would that look like? For the latter question, Graihagh speaks to the largest sustainable certifier of palm oil, the RSPO and looks to science to see how we can continue to grow palm oil without having any more adverse effects on wildlife. This episode is part of the Crossing Divides season which runs from 18 - 24 November. You can find a link to the Food Chain episode below.Produced and presented by Graihagh Jackson with help from Marijke Peters and editor Rami Tzabar for the BBC World Service.(Photo: Woman shopping in supermarket Credit: Getty Images)

For decades science fiction has been imagining the incredible ways that machines might interact directly with our minds, from enabling telepathic communication to controlling robotic suits, solely using the power of thought. Getting computers to interface directly with the human brain has proven extremely challenging, but rapidly advancing computer technology is changing the landscape. CrowdScience listener Daniel wonders if we might finally be on the cusp of enabling machines to meld with our minds. To find out, presenter Alex Lathbridge goes in search of the latest efforts to connect brains to computers. He learns how researchers are combining brain scans with machine learning and gets to test whether an fMRI machine can decode his emotions. He then meets someone with a brain implant but discovers there are many hurdles to overcome before these become mainstream in clinical practice – for example, how can scientists develop implants that won’t damage the brain? With tech companies like Facebook and Elon Musk’s Neuralink starting to invest in this sector, many experts believe it is only a matter of time before thoughts are ‘readable’. Whilst currently this technology is focussed on helping people with serious medical conditions, other potential applications for it are raising ethical considerations. Could it be possible to read someone's mind against their will? Might this be used in warfare? Listener Daniel wonders how far this technology might go, leading Alex to ask an ethicist what mind-reading technology might do to society.Presented by Alex Lathbridge Produced by Melanie Brown(Photo: Telepathic people symbols are connected, mind reading as 3D illustration. Credit; Getty Images)

We’re all familiar with the sensation of sleepiness – heavy eye-lid, that warm, fuzzy feeling. But, one CrowdScience listener wants to know, what’s actually going on in our body and brain when tiredness takes over?Presenter Marnie Chesterton takes up the challenge and follows a trail that leads to circadian scientists working at the NASA Ames research centre in Silicon Valley. It turns out aviators and astronauts take sleepiness very seriously indeed.Marnie sends out roving reporter Anand Jagatia to investigate how our psycho-motor skills are affected by fatigue in a driving simulator. And we ask how does sleepiness change with age? Why, when tired, do adults crave a nap but children become ever more excitable? And what the hell’s going on with teenagers? We have some answers.Presented by Anand Jagatia Produced by Dom Byrne (Photo: Tired woman taking a nap at work sitting at office desk. Credit: Getty Images)

Most of us take the ability to speak fluently for granted, but for listener Breeda it has been a lifelong struggle. She has asked CrowdScience to investigate whether there is a cure for stuttering and, if not, what the best way to live with it is. Breeda is not alone, as stammering is a neurological condition that affects 70 million people worldwide. The CrowdScience team head to Oslo in Norway to follow a group of young people who have signed up for a highly disciplined and potentially life-changing training course. The first milestone is to learn to say their name without a stutter. For many, this is a huge challenge that triggers years of distress and anxiety.With hundreds of muscles and many parts of the brain being involved, speaking is one of the most complex tasks that humans perform. Scientists have discovered subtle differences in the insulation surrounding nerve cells, so-called myelin, between people who stutter and those who don’t. This irregularity may be the source of a tiny time delay in signals between crucial regions of the brain that need to work closely together to produce speech. In the future, it may be possible to stimulate certain brain areas to boost growth and connectivity.Presenter: Gareth Barlow Produced by Louisa Field for the BBC World Service(Image: Illustration of humans speaking with quotation marks, credit: Getty Images)

Crowdscience listeners Michael and Ricky have been walking a tributary of the River Thames in London, UK. They’ve noticed that there are loads of fish, which have only returned in recent years thanks to clean water initiatives. But what about salmon, they wonder? Could they one day return too? If they popped some salmon eggs in the river, would they return to spawn later on in their lives? Marnie Chesterton heads to Norway to find out whether it’s possible. There, she follows the life cycle of salmon, from birth to death and travels to the salmon’s spawning grounds, before following their path out to sea and beyond. She explores the science behind ‘natal homing’ - returning to the place of your birth in order to reproduce. It isn’t just confined to salmon. But how does it work? Marnie also learns to fish as she joins an active research project that's evaluating if escaped farmed salmon are threatening their wild counterparts by interbreeding. Could this stop salmon swimming home?Back in the UK, Marnie finds out if all this Norwegian expertise could be transplanted to a river in London? Quite possibly, but it's not without its challenges, as the UK's Environmental Agency found out after attempting to re-introduce salmon into the River Thames.Presenter: Marnie Chesterton Produced by Graihagh Jackson for the BBC World Service(Photo: The mighty Wild Atlantic salmon travelling to spawning grounds in the Scottish highlands. Credit: Getty Images)

Faced with one cake and eight hungry people, it’s pretty obvious how maths underpins reality. But as mathematics gets further from common sense and into seemingly abstract territory, nature still seems to obey its rules - whether in the orbit of a planet, the number of petals on a flower, or the structure of an atom. But what exactly is the relationship between mathematics and reality? That’s the impossibly difficult question CrowdScience has been set this week by our listener Sergio in Peru. It’s one that’s been pondered by humans for millennia: the Greek philosopher Pythagoras believed “All is number”. Is maths a human construct to help us make sense of reality - a tool, a model, a language? Does maths create its own reality? Or is it reality itself?CrowdScience explores these questions with the help of experts from the fields of philosophy, mathematics and science: Dr Eleanor Knox, Dr Eugenia Cheng, Professor Lucie Green, Alex Bellos and Stefano Centineo. Presenter: Marnie Chesterton Produced by Cathy Edwards for the BBC World Service(Photo: A young woman with her eyes closed standing in front of chalkboard, working out maths formulas. Credit: Getty Images)

Human life expectancy has been increasing for decades. In many developed countries, we can now expect to live into our 80s, and it isn’t uncommon to live to 90 or even 100 years old. But eventually our bodies fail, old age is undoubtedly a clear indicator of approaching death. This fact annoyed 79 year old CrowdScience listener Bill, who emailed in to set presenter Geoff Marsh the task of seeking out the secrets to a longer, healthier life. Bill has a personal target to live to 200 years old, so can he do it? Well some people appear to age more slowly. In one part of Costa Rica, people commonly hit their hundredth birthday. CrowdScience’s Rafael Rojas visits these Central American centenarians to ask them their secrets to a longer life. Then, in interviews with the best age researchers around the world, including Professor Linda Partridge and Professor Janet Lord, Geoff reveals the science behind longer lifespans, and what people can do to live for longer, healthily. Presented by Geoff Marsh Produced by Rory Galloway(Image: A group of older men sitting together at an event, Costa Rica. Credit: Rafael Rojas)

The number of vegans is on the rise in many parts of the world, with many people swearing by the health benefits of a plant-based lifestyle. But is a vegan diet really better for your health? Is there any evidence to show that vegans are likely to live longer? And what about the new, highly processed meat analogues becoming increasingly available in supermarkets and restaurants menus? They look, feel and taste just like meat products but what affect are they having on our health? To find out more, presenter Anand Jagatia talks to the experts and joins listener Samantha in following a vegan diet. Presenter Anand Jagatia Produced by Caroline Steel for the BBC World Service(Photo: Healthy vegan food with herbs and spices. Credit: Getty Images)

Sir Arthur Conan Doyle’s famous fictional detective is renowned for his feats of memory, his observational capacity, tireless energy and an almost supernatural ability to solve the most perplexing crimes from seemingly unconnected facts.CrowdScience listener Asghar wants to know whether the way Sherlock Holmes solves crimes goes beyond fiction. What does science have to say about the matter? We pit fact against fiction with a leading forensic expert, a sleep scientist and presenter Marnie Chesterton puts herself to the test under the guidance of memory champion Simon Reinhard. She discovers that most humans are able to train their brain to rival the memory capacity of Sherlock Holmes. And who wouldn’t want that?Presenter: Marnie Chesterton Producer: Louisa Field(Photo: A Sherlock Holmes hat and magnifying glass on a wooden table. Credit: Getty Images)

The World Health Organization ranks migraines as the second most disabling neurological disorder in the world and in people under the age of 50, it is the single most disabling medical condition. With stats like that, it’s no wonder that so many CrowdScience listeners have got in touch wanting help with their headaches. Peter from Germany askes what happens in his brain when he’s got a migraine, whilst Nika from Germany has found that changing lifestyle has dramatically reduced hers but she’s not sure why. What’s the link between diet, exercise and migraines, Nika wonders? Meanwhile, Judy from USA wants to know if there’s a cure, as her son gets chronic migraines and she wants to know what the future looks like for him.Anand Jagatia and migraine sufferer Graihagh Jackson take a trip into the neurology of migraines, investigating some of the latest research in headache and migraine research to find some answers. Presenters: Anand Jagatia & Graihagh Jackson Producer: Graihagh Jackson(Photo: A young man suffering from a migraine. Credit: Getty Images)

Sociable, lively, outgoing people are highly valued in certain cultures - think of the stereotype of the hyper-confident American. And there’s even evidence that extroverts all over the world tend to be happier. But are the positive qualities that quieter types can bring to society being ignored or underappreciated? And couldn’t introverts be just as happy as extroverts, if only they lived in a more accepting culture? These are controversial areas of personality psychology into which CrowdScience strayed earlier this year when exploring the question “Why am I shy?” It prompted a whole bunch of other questions from our listeners which we tackle in this follow-up programme, with the help of psychologist and shyness expert Professor Jonathan Cheek. We probe the links between happiness, personality and culture, and find out what makes introverts happy.Presenter: Datshiane Navanayagam Producer: Cathy Edwards(Photo: A woman smiling with her arms spread out. Credit: Getty Images)

Satellites have transformed our lives, giving us digital communications, navigation and observations of Earth, and even an artificial place to live above the atmosphere: The International Space Station. CrowdScience listener Dana wants to know: would more of these satellites and stations help us get back to the Moon, as well as further into the solar system? As we discovered in a previous episode, being able to mine resources such as fuel and water in space could be handy for extra-terrestrial exploration. Asteroids could perhaps one day become self-fuelling gas stations for spaceships, as many contain ice which you could turn rocket fuel (hydrogen and oxygen). But what else would astronauts need for living beyond Earth? Marnie Chesterton asks the engineers working on the possibilities – from communications satellites that could transform lunar missions to a brand new moon-orbiting space station: The Lunar Gateway. These technologies could help humans get back to the Moon, and perhaps one day to Mars, for hopefully reduced costs – but funding missions beyond our planet still isn’t going to be cheap. Why might we need deep space-based infrastructure, and how could it help humanity back here on Earth? Presented by Marnie Chesterton Produced by Jennifer Whyntie for the BBC World Service(Photo: International Space Station, orbiting Earth. Credit: The Science Photo Library)

Many of us struggle to motivate ourselves to carry out certain tasks, from hanging out the washing to writing a job application. How can we best motivate ourselves? And how can we avoid procrastination? Listener Moses in Uganda wants to find out. Presenter Anand Jagatia puts the science to the test as he trains and participates in an open water swimming race which Marnie Chesterton has kindly volunteered him for. Presented by Anand Jagatia and Marnie Chesterton Produced by Caroline Steel for the BBC World Service(Photo: Yes you can, motivational message written on a sandy beach. Credit: Getty Images)