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Professor Dale Sanders has spent much of his life studying plants, seeking to understand why some thrive in a particular environment while others struggle. His ground breaking research on their molecular machinery showed how plants extract nutrients from the soil and store essential elements. Since plants can’t move, their survival depends on these responses. In 2020, after 27 years at the University of York, he became the Director of the John Innes Centre in Norwich, one of the premier plant research institutions in the world. Meeting the food needs of a growing global population as the climate changes is a major challenge. And, Dale says, it’s not only about maximising yields. We need crops that are more resilient and more nutritious. Drought resistant crop varieties, for example. And zinc-rich white rice. Dale talks to Jim about how plant science is helping to feed the world in a sustainable way and why plant scientists don’t always get the recognition they deserve. Producer: Anna Buckley

Professor Andrew Fabian from Cambridge's Institute of Astronomy has spent his career trying to unravel the mystery of how some of the most dramatic events in the universe can profoundly influence its evolution. For over 50 years he’s been examining our universe using X-ray satellites orbiting way above earth’s atmosphere . He’s built up compelling evidence that supermassive black holes at the heart of galaxies are the engines that drive the movement of energy through the universe and provide the building blocks for the formation of new galaxies. They're extraordinary insights, for which he’s now been awarded the 2020 Kavli Prize in Astrophysics, one of the world's most prestigious science prizes. Jim Al-Khalili hears how Andy gets to capture epic galactic events in motion to build up a picture of this vast ecosystem - and also how he earned a place in the Guinness Book of Records for discovering the deepest note in the universe – a B flat , 57 octaves below middle C. Producer Adrian Washbourne

Professor Heather Koldewey wants to protect our oceans from over-fishing and plastic pollution. An academic who is not content to sit back and let the science speak for itself, she wants to turn science into action and has found conservation allies in some unexpected places. Working with a carpet manufacturer, she created Net-Works, a business that turns old fishing nets into high-end carpet tiles and she has collaborated with Selfridges department store to give marine conservation a make-over. A research career that began studying the genetics of brown trout in Welsh rivers took her to the Philippines to save seahorses and a job running the aquarium at London Zoo. In 2018, she was made a National Geographic Fellow. Heather tells Jim Al-Khalili why, despite all the challenges to marine life, she remains an ‘ocean optimist’ and how she learned to drop her ‘scientific seriousness’.

The year 2020 started with wildfires raging across parts of Australia, exceptional floods in East Africa, and a heatwave in the Arctic. Extremes persisted through the year in the north - where wild fires consumed record areas in Siberia, and the Arctic ice reached record lows. Death Valley saw the highest reliable temperature yet recorded on the planet, while the Atlantic saw the most active hurricane season on record. An extreme year by many measures, and one that could end up as the hottest on record globally. Roland Pease asks what it tells us about global warming. Picture credit: Wegener Institute / Steffen Graupner

Less than a year in, and the first vaccines are already being rolled out, with many more in the pipeline. It is an unprecedented scientific response to the global pandemic and researchers around the world have provided the first hope against one of the most formidable challenges facing humanity in a century. Claudia Hammond and her expert panel of guests consider the scale of this herculean effort and answer listeners' questions about vaccine safety, trust, immunity, and long term protection. The World Health Organisation has repeatedly said that no-one is safe until we are all safe, so the threat of vaccine nationalism and the purchase of millions of the first vaccine doses by rich countries is something that is concerning everybody worried about equitable vaccine distribution. How will the COVAX facility, which is designed to boost vaccine purchasing power for the world's poorest countries, fare in the face of nationalistic purchasing - and will surplus doses be shared so that all seven point five billion of us can get protection? And, finally, the scale of the threat from vaccine hesitancy. Any vaccine is only as good as the number of people who will take it to achieve herd immunity. The numbers of those suspicious about a potential Covid-19 vaccine have grown over the course of the pandemic, causing real concern for governments around the world. How can people be reassured that vaccines are safe? This month, Claudia's guests include Professor Peter Hotez, Dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston and co-director of the Texas Children's Hospital Centre for Vaccine Development in the USA, Professor Helen Rees, founder and executive director of the Wits Reproductive Health and HIV Institute, the University of Witwatersrand in South Africa, Kalipso Chalkidou, Professor of Practice in Global Health at Imperial College, London and Director of Global Health Policy at the Centre for Global Development and Dr Ève Dubé, a medical anthropologist from the Institute of Public Health in Quebec, Canada. Produced by: Fiona Hill, Samara Linton and Maria Simons Editor: Deborah Cohen Technical Support: Tim Heffer and Giles Aspen Picture: Covid-19 Vaccination Clinics Open In Surrey, UK, Credit: Leon Neal/Getty Images

It’s amazing what we can learn from a pile of old bones. Having worked as a paediatric surgeon for several years (often doing the ward round on roller blades), Alice Roberts spent a decade teaching anatomy to medical students and studying human remains. A niche interest in the collar bone and how it has changed since we evolved from the common ancestor we share with other apes 6 million years ago, led her to some of the biggest questions in science. Who are we? And where do we come from? She is the presenter of several landmark TV series on human evolution and archaeology, such as The Incredible Human Journey and Digging for Britain. And in 2019 she became President of the British Science Association. In conversation with Jim Al Khalili, Alice shares her passion for the bones of our ancient ancestors and of the freshly dead, and describes her own incredible journey from a basement full of medieval bones to an eminent science communicator and public figure. Producer: Anna Buckley

Steve Haake has spent much of his career using technology to help elite sports people get better, faster and break records. He has turned his hand to the engineering behind most sports, from studying how golf balls land, to designing new tennis racquets and changing the materials in ice skates. He’s now Professor of Sports Engineering at Sheffield Hallam University and was the Founding Director of the Advanced Wellbeing Research Centre there. Since the 2012 London Olympics, Steve has also been working to improve the health and wellbeing of all of us. As Chair of the Parkrun Research Board he’s heavily involved in this international phenomenon in which thousands of people have sprinted, jogged and stumbled around a 5-kilometre course on Saturday mornings, which he’s shown really does encourage people to be generally more active. Jim al-Khalili talks to Steve Haake about how he got from a physics degree to being one of the leading sports engineers in the world, and how we can all improve our health by moving more.

Is there a point in space where the Sun could heat a burrito perfectly? asks Will. The doctors tackle this and a plethora of other conundrums from the Curious Cases inbox. Featuring expert answers from astrophysicist Samaya Nissanke, cosmologist Andrew Pontzen, and cognitive neuroscientist Sophie Scott. Presenters: Hannah Fry & Adam Rutherford Producer: Jen Whyntie

Today I learnt that tigons and ligers are what you get when lions and tigers interbreed?!’ surprised listener Jamz G tells the doctors. ‘What determines whether species can interbreed?’ Geneticist Aoife McLysaght studies molecular evolution. She explains the modern definition of a species, built on ideas from Aristotle, Linnaeus and Darwin: a species is a group of organisms capable of interbreeding to produce fertile offspring. Hybrids – such as ligons and tigers – are usually infertile, because their common ancestors long ago diverged into the lions and tigers we know today. However, this definition isn’t absolute, and there are many ways a new species can be formed. Hybrids also offer rich study subjects for scientists. Mathematical biologist Kit Yates discusses why he’s been reading research papers about hebras and zorses (horse x zebra) as their patterns offer insights into how cells spread and develop into organisms, building on a prediction made by codebreaking mathematician Alan Turing. And it turns out that these hybrids are even more intriguing. As speciation and evolution expert Joana Meier explains, hybrids are not always infertile. Hybridisation can lead to successful new species arising, such as in Lake Victoria’s cichlid fish, who it seems have been having a wild evolutionary party for the last 15,000 years. And the picture gets even murkier when we discover that modern genetics reveals our human ancestors successfully mated with Neanderthals. Presenters: Hannah Fry & Adam Rutherford Producer: Jen Whyntie

Millions of us, across the world, are subject to curfews, stay-at-home orders and lockdowns but what makes us stick to the rules, bend them or ignore them altogether? Claudia Hammond and her expert panel of guests consider the psychology of following the rules. Leading social psychologists share research which show that higher levels of trust in leadership translates to more pandemic guidance followed. A sense of “We” not “I”, a shared identity, makes a difference too, as well as identification with the whole of humankind, not just your immediate family. But there is danger too, from a “narrative of blame”, where individuals are demonised if they break the rules. Such an approach, Claudia hears, is corrosive to the all-important sense of shared identity and alienates some groups, while making others complacent. Also in the programme, what impact can rapid “have you got it” antigen tests which give results in minutes, rather than days, have on the virus? Claudia hears from the Cameroon in Central, West Africa, one of the first countries in the world to try mass testing using these rapid diagnostic tests. And she talks to scientists at the forefront of evaluating and modelling how their use could affect transmission of the virus, and daily life for all of us, until a vaccine is available. This month, Claudia’s panel of specialists answers BBC World Service listeners’ questions and includes Professor Michael Mina, Assistant Professor of Epidemiology Immunology and Infectious Diseases at Harvard TH Chan School of Public Health in USA, Dr Margaret Harris, from the World Health Organisation in Geneva, Switzerland, Steve Reicher, Professor of Social Psychology at St Andrews University in Scotland, Professor Rolf Van Dick, social psychologist and Vice President of the Goethe University in Frankfurt, Germany and Dr Jilian Sacks, senior scientific officer for Pandemic Preparedness for FIND, the Foundation for Innovative New Diagnostics in Geneva.

Everyone knows about the Big Bang being the beginning of the universe and time - but when and how is it going to end? ask brothers Raffie and Xe from Rome. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. The doctors sift science from philosophy to find out. Cosmologist Jo Dunkley studies the origins and evolution of the universe. She explains how astrophysical ideas and techniques have evolved to tell us what we now know about our galaxy and far beyond, from the elegant parallax technique to standard candles. This particular distance measure, which uses stars of a known brightness to work out how far away other objects in the universe are, was discovered by American astronomer Henrietta Swan Leavitt in 1912, who worked at the Harvard University as one of several “computers” – women who processed and calculated data and made significant contributions to astronomy. Curious Cases’ universal guru Andrew Pontzen puts this into context. Because the universe is so enormous, it turns out that these measurements are just the first steps on the cosmic distance ladder – a suite of tools that astrophysicists use to determine distances to celestial objects. Scientists know that objects are moving away from us because the wavelengths of light from them get stretched and appear redder in our telescopes – the so-called red shift effect. But having a handle on the distances to and between those objects allows cosmologists to monitor what’s happening to them over time. And it turns out that not only are they getting further apart, indicating that the universe is expanding, but that this process is accelerating. So what might happen in the end? Expansion and then collapse – a big crunch? Expansion into the void – a big freeze, or a big rip? Or what if there is more than one universe – might a new one bubble up with totally different laws of physics that would cause our own to cease existing? It turns out that when dealing with predictions for something involving infinite space and time, the possibilities are largely limited by human imagination alone. Ideas are where science starts, but experiments are required to build evidence confirming or rejecting them as fact. The doctors discuss how gravitational wave detectors and quantum computers might one day provide this. Presenters: Hannah Fry & Adam Rutherford Producer: Jen Whyntie

Autism is a lifelong condition, often seen as particularly ‘male’. Yet a growing number of women, and those assigned female at birth, are being diagnosed as autistic in their 30s, 40s, 50s, and beyond. Writer and performer Helen Keen is one of them, and she’s found this diagnosis has helped her make sense of many aspects of her life, from growing up with selective mutism, to struggling to fit in as a young adult. In this programme Helen asks why she, like a growing number of others, had to wait till she was well into adulthood before finding her place on the autistic spectrum. She discovers that for many years psychologists believed that autism was rarely seen in women and non-binary people. Now it is accepted that people often display autistic traits in different way - for example, they may learn to ‘camouflage’ and behave in a neurotypical way - but at what cost? Helen talks to others like her who have had late diagnoses, and finds out if knowing they are on the autistic spectrum has given them insight into how they can navigate the pressures on them from contemporary society. She also explores how we can value and celebrate neurodiversity. Helen also talks to psychologists Professor Francesca Happé, of the Institute of Psychiatry, Psychology and Neuroscience in London, and Dr Steven Stagg of Anglia Ruskin University about their research into autism. Picture: Geometric camouflage pattern, Credit: Yuri Parmenov/Getty Images

As large areas of the world have locked down this year, many of us have become more aware of the birdsong around us. The relative silence has allowed us to listen in. But scientists have known for several years that the birds themselves have been responding to human noise too, by pitching their songs and other calls higher, to be heard over the rumble of our urban life. There are several ways in which birds can adapt how they communicate in the face of environmental pressures, but what are the limits to these adaptations? And what can this tell us about how to maximise conservation efforts in the future? Rory Crawford talks to ornithologists and animal behaviourists studying bird species around the world. He finds out how the advance of technology is helping researchers explore birds’ preferences and behaviours in the wild, and hears how one particular bird changed its song, and the new version rapidly spread across North America – “the most viral tweet of all time”, as it’s been called! Picture: A Robin [Erithacus rubecula], Credit: Gary Chalker/Getty Images

Claudia Hammond asks if touch can be replicated digitally? What devices exist already and how likely are we to use them? Michael Banissy, co-creator of the Touch Test, neuroscientist David Eagleman and researcher Carey Jewitt look at the possibilities for touch technologies in the future. David has developed a wristband that translates sound into touch for deaf people, Carey looks at the ethics of digital touch and Michael reveals the attitudes from the Touch Test towards digital technologies. If we could replicate the feeling of holding a loved one's hand in hospital would it really be the same? And dancer Lisa May Thomas talks about her experience of extending touch into space and through virtual reality.

As a surge of cases risks overwhelming health services in parts of Europe, Claudia Hammond and experts from around the world examine the evidence behind using lockdowns to supress the virus. Lockdowns describe a huge range of actions that many governments took in the first wave of the pandemic when so little was known about where the virus was circulating. But full lockdowns are seen as very blunt tools, a last resort because they can have enormous social and economic consequences. Instead a more targeted, localised, smarter response to slow down transmission is recommended, where data about virus circulation informs focussed interventions. Also in the programme, The Great Barrington Declaration earlier this month called for an end to current lockdown policies and appealed for the vulnerable to receive “focussed protection” while everybody else “should immediately be allowed to resume life as normal”. The goal, the group of scientists said, should be to minimise deaths and social harm, until herd immunity, or population immunity, is reached. The World Health Organisation has described such a strategy as dangerous and counterproductive. Claudia’s guests discuss the scientific and ethical issues raised and consider the scale of global exposure to this novel virus. So far only around 10% of the world’s population have been infected so what would a policy of herd immunity in the absence of a vaccine mean for the remaining 90%? Listeners put their questions about coronavirus and the pandemic directly to Claudia and her panel of specialists, which this month includes Dr Maria Van Kerkhove, Technical Lead for the World Health Organisation’s Covid-19 Response; Professor Salim Abdool Karim, a clinical infectious diseases epidemiologist and Chair of South Africa’s Ministerial Advisory Committee for Covid-19; Martin McKee, Professor of European Public Health at the London School of Hygiene and Tropical Medicine and one of the signatories to the John Snow Memorandum; epidemiologist Tove Fall, Professor at Uppsala University in Sweden running the Covid-19 symptom app and virologist Professor Steven Van Gucht, from Sciensano, the Belgian national institute for public and animal health. The Evidence is produced in association with Wellcome Collection. Production team: Fiona Hill and Maria Simons Studio engineer: Jackie Margerum Editor: Deborah Cohen

Claudia Hammond looks at the neuroscience behind our sense of touch. Why does a gentle touch from a loved one make us feel good? This is a question that neuroscientists have been exploring since the late 1990's, following the discovery of a special class of nerve fibres in the skin. There seems to be a neurological system dedicated to sensing and processing the gentle stroking you might receive from a parent or lover or friend, or that a monkey might receive from another grooming it. Claudia talks to neuroscientists Victoria Abraira, Rebecca Bohme, Katerina Fotopoulou and Francis McGlone who all investigate our sense of emotional touch, and she hears from Ian Waterman who lost his sense of touch at the age of eighteen.

Claudia Hammond explores unwanted touch and who we do and don’t mind touching us – and where. She draws on insights from the largest study that’s ever been conducted on the topic of touch – The Touch Test - commissioned by Wellcome Collection. Almost forty thousand people from all over the world chose to take part. Claudia discusses where we draw the boundaries between acceptable and unacceptable touch, at work or in the street, with Dr Amy Kavanagh, a visually impaired activist and campaigner, Joanna Bourke, Professor of History at Birkbeck, University of London and the author of “Rape - a History”, and Dr Natalie Bowling, a psychologist at the University of Greenwich who co-created the Touch Test and has been crunching the numbers. After #meToo and Covid, could unwanted touch even become a thing of the past?

Drought is a massive problem for Chile. Jane Chambers has been living in the capital Santiago for more than ten years and has seen huge changes in that time. It used to rain frequently in the winter months between June and September and the Andes Mountains which run down the whole of Chile were snow-capped all year round. But that doesn’t happen anymore. Jane reports on the impact of the mega drought on the country and what is being done about it. She talks to climate scientists Sebastian Vicuna, Director of the Global Change Research Centre, at the Catholic University of Chile and to Rene Garreaud, a Professor in the Geophysics Department at University of Chile and Deputy Director of the Center for Climate and Resilience Research, about whether the megadrought is the result of natural weather patterns or of climate change. She meets farmers who are struggling to find pasture for their goats in the village of Til Til, and Francisco Meza, a Professor in the department of agriculture and forestry at the Catholic University in Santiago, who is helping agriculture adapt to low rainfall. And Jane hears about ways to increase the availability of drinking water through small-scale desalination and by capturing moisture from the air. Picture: Flows of rivers and reservoirs have reached historic minimums in Chile. A severe drought is hitting the country's central area, making local communities more vulnerable to face the coronavirus pandemic. (Photo by MARTIN BERNETTI/AFP via Getty Images)

"What’s the point of wasps?" asks listener Andrew, who is fed up with being pestered. For this series, with lockdown learning in mind, Drs Rutherford and Fry are investigating scientific mysteries for students of all ages. Do wasps do anything to justify their presence as a picnic menace? Ecologist Seirian Sumner researches social wasp behaviour and champions their existence. Not only do yellow jacket wasps perform important ecological services as generalist pest controllers of aphids, caterpillars and flies in the UK, they have complex societies and may even perform pollination services, making them more like their better-loved bee cousins than many might think. However, much remains unknown about wasps’ contribution to our ecosystem. Seirian works with entomologist Adam Hart, and together they run The Big Wasp Survey each summer, a citizen science project dedicated to find out more about UK wasp species and their populations. Prof. Hart sets up an experimental picnic with Dr Rutherford to try and attract some native wasps, and discusses why they are so maligned. But in some parts of the world UK wasp species have become a major problem. Just after World War II, having unwittingly chosen some aircraft parts destined for New Zealand as their overwintering home, some wasp queens woke up in the city of Hamilton. With no natural predators or competitors, they quickly established a growing population. Fast forward to today, and by late summer the biomass of wasps becomes greater than all the birds, rodents and stoats in the southern island’s honeydew beech forests. Multiyear nests have been discovered that are over three metres tall and contain millions of wasps. Researcher Bob Brown is digging into wasp nests back in the UK to discover which species keep wasps in check here, and whether they might work as biological control. This causes the doctors to ponder the problems of humans moving species around the planet. Accidental or even well-meaning introductions all too often become invasive. As climate change and urbanisation accelerate, wasps may become more helpful in some ways and more harmful in others. Presenters: Hannah Fry, Adam Rutherford Producer: Jen Whyntie

Claudia Hammond and experts from around the world consider the evidence behind schools, colleges and coronavirus spread. Listeners from India, Cuba, Italy, Brazil, Canada, Hong Kong, France, the USA pitch their questions to the specialists. Research so far shows a low risk of transmission but as children and young people return to classrooms across the globe, will that remain the case? And Claudia and the team look at that vital role of “test, trace and isolate” when it comes to SARS-CoV-2, something the World Health Organisation describes as the backbone of any Covid-19 response. Which countries are getting this right and what can others learn from the best? New research comparing six countries from Europe, Africa and Asia highlights the successes and the failures. Plus Kat, a nurse from Kansas City, Missouri gives a first hand account of pandemic response in the USA and then, when she moved to Germany in the summer, from Stuttgart. On the panel are Dr Regina Osih, an infectious disease and public health specialist from the Aurum Institute in South Africa who’s working on the country’s Covid response, Dr Young June Choe, paediatrician and assistant professor at Hallym University in South Korea, Gail Davey, Professor of Global Health Epidemiology at Brighton and Sussex Medical School in England, David Heymann, Professor of Infectious Disease Epidemiology at the London School of Hygiene and Tropical Medicine from France and Dr Margaret Harris from the WHO in Geneva. The Evidence is produced in association with Wellcome Collection. Production team: Fiona Hill, Samara Linton and Maria Simons Studio engineers: Matilda Macari and Tim Heffer Editor: Deborah Cohen