CrowdScience

When some people are wandering around in shorts and a t-shirt, others are wrapped up in warm coats and jumpers. How come our responses to cold weather are so different? People have been living in cold environments for thousands of years. So why do some of us struggle with the cold more than others, and what, if any, adaptations have our bodies made to cope in freezing temperatures? CrowdScience listener Anne from the UK is amazed by the warm houses of her neighbours, and wants to know whether her background might have affected her perspective on the cold. Caroline Steel investigates, visiting a laboratory in Loughborough University, UK, that pushes the body to the extreme. Dr Matt Maley explains what happens inside our systems to help us survive the plummeting thermostat and how this adaption can vary from person to person. But it’s not just biological. Our culture impacts our experience of cold too. CrowdScience heads to Norway to meet the global community on the icy Arctic island of Svalbard. There Caroline meets Associate Professor Gunhild Sætren at the Arctic Safety Centre to find out the important role appropriate clothing plays in being prepared for the chilly weather. And we speak to Dr Cara Ocobock at the University of Notre Dame, USA, who tells us about her research comparing Finnish reindeer herders and office workers reactions to cold temperatures. Presenter: Caroline Steel Producer: Hannah Fisher Editor: Ben Motley(Photo: Woman enjoying winter playing in fresh snow. Credit: Olga Pankova/Getty Images)

Smashing up guitars is a classic rock star activity, but how about drowning them? Seven-year-old listener Cornelius asked CrowdScience to find out what happens if you play a guitar underwater. Could this be the next avant-garde music sensation? Host and amateur musician Caroline Steel tackles Cornelius’ question with the help of one increasingly soggy guitar. The UK’s National Physical Laboratory is our first port of call, with a guitar-sized water tank at the ready, and acoustic scientists Dr Freya Malcher and Ben Ford helping tackle our questions. Since an acoustic guitar’s sound is amplified by its internal chamber, what happens as that chamber starts to fill with water? How about if the whole guitar - strings, body and all - is submerged? What difference does it make if our ears are listening above or below the water? And can special water-adapted microphones help us explore this unusual question, before our guitar disintegrates? Our guitar then heads off on tour to Denmark, where the band Between Music have teased out questions just like these for their underwater music project, Aquasonic. We talk to violinist and Innovative Director Robert Karlsson, and singer Nanna Bech, who also plays a unique subaquatic instrument. With their help, we discover how to get the best out of a submerged guitar, and find out whether other instruments are better suited to the life aquatic. Presenter: Caroline Steel Producers: Cathy Edwards and Florian Bohr Editor: Ben Motley (Photo: Caroline Steel and Nanna Bech in an Aquasonic aquarium playing a guitar)

Can we turn the world’s deserts green? CrowdScience listener Youcef is captivated by the idea of bringing water back to Earth’s driest landscapes. With sea levels rising and huge stretches of land drying out each year, he wonders whether redirecting seawater inland could offer a solution to both problems. Presenter Alex Lathbridge sets out to investigate starting with a kettle of salty water. Alex speaks to scientists about how deserts form, and how human actions like overgrazing can tip a fragile grassland into a barren landscape. He learns how the brightness of bare sand affects local weather, reducing cloud formation and rainfall. Researcher Yan Li reveals how huge solar and wind farms could darken and roughen the Sahara’s surface enough to double its rainfall, potentially kickstarting a self-reinforcing cycle of vegetation and moisture. But what about deserts where clouds already drift overhead? In the Atacama, one of the driest places on Earth, geographer Virginia Carter shows how fog harvesting nets can coax litres of fresh water from the air. Alex also investigates desalination, where professor Chris Sansom is trying to harness solar power to remove the salt from seawater without burning vast amounts of fossil fuels. It is promising, but can it reduce the impact of rising sea levels? And what do you do with all the salt that’s left over? Climate scientist Alan Condron proposes an even wilder idea: towing kilometre-sized icebergs from Antarctica to parched nations. His models show it might be possible, but the logistics verge on science fiction. Finally, plant scientist Zinnia Gonzalez Carranza warns that greening deserts isn’t just about adding water. Introducing new species, even hardy ones like mesquite, can trigger ecological chaos and harm the very communities who depend on these landscapes. Presenter: Alex Lathbridge Producer: Sam Baker Editor: Ben Motley (Photo: Palm trees growing in cracked, parched earth and the sun rising behind them. Credit: Danymages/Getty Images)

When listener Sakura’s husband came home from his morning walk in Cambridgeshire, UK, he told her about a massive rainbow he’d seen. But when he showed her a picture, she didn’t think it was particularly large. So how big is a rainbow really? Are they always the same size? And if some are bigger than others, is there a limit? To find the answers, presenter Marnie Chesterton meets independent rainbow expert Philip Laven in a pitch-black studio to simulate how a rainbow is formed. He demonstrates how they are created by sunlight, reflecting and refracting in millions of little water droplets. But what does that mean for their size? Raymond Lee, retired professor from the US Naval academy, says that rainbows are not objects and don’t have a linear size, just a specific angular size that’s relative to the person seeing it. But Marnie doesn’t give up so easily – some rainbows still look bigger than others. In her journey to discover other ways to size up a rainbow, Marnie hears from Australian aerial photographer Colin Leonhardt who stunned the world with a beautiful picture. Next, assistant professor Ping Wah Li from The Chinese University of Hong Kong explains why it’s possible to come across more than one rainbow at a time. And finally, atmospheric scientist Harald Edens shares another way to consider size, as well as how much he struggles to explain the complexity of rainbows to his four-year old daughter. Presenter: Marnie Chesterton Producer: Florian Bohr Editor: Ben MotleyPhoto: Rainbow of Dreams - stock photo stock photo Credit: Laurent Fox via Getty Images)

Tears of joy, tears of sadness, tears of frustration or tears of pain - humans are thought to be the only animals that cry tears of emotion. CrowdScience listener Lizzy wants to know: why do we cry for emotional reasons? What is its evolutionary benefit? And why do some people cry more than others? It turns out that humans cry three types of tear: basal, reflex and emotional. The first kind keeps our eyes nice and lubricated and the second flushes out irritants such as fumes from the pesky onion, but the reasons for emotional tears are a bit harder to pin down. Using a specially designed tear collection kit, presenter Caroline Steel collects all three kinds of tears. With them safely stashed in tiny vials, she heads to the Netherlands, to Maurice Mikkers’ Imaginarium of Tears. Looking at her crystallised tears under a microscope will hopefully unveil a mystery or two. Marie Bannier-Hélaouët, who grew tear glands for her PhD, explains how the nervous system processes our emotions into tears. But why should we cry for both happiness and sadness, and for so many other emotions in between? Ad Vingerhoets, Professor of Clinical Psychology at Tilburg University, suggests we cry for helplessness - our bodies do not know how to process such intensity of feeling. But do these tears bring relief? Lauren Bylsma, Associate Professor of Psychiatry at the University of Pittsburgh, has been studying heart rates during crying episodes to find out. With her help, we also explore if women do in fact cry more than men, and why that might be. Presenter: Caroline Steel Producer: Eloise Stevens Editor: Ben Motley Photo: Fisheye woman having a cry - stock photo Credit: sdominick via Getty Images)

Tsunamis destroy buildings, habitats and danger to everything in its path on land. But how do they affect life under the water? That's what CrowdScience listener Alvyn wants to know, and presenter Anand Jagatia is searching beneath the waves for answers. Anand meets Professor Syamsidik who is learning about how tsuanami waves are formed to help protect against future disasters. He runs the Tsunami and Disaster Mitigation Research Center at Universitas Syiah Kuala, Indonesia. With him at this state-of-the-art lab is Dr David McGovern, expert in ocean and coastal modelling at London South Bank University. David tells Anand how the energy of a tsunami is spread across the entire water column. To explain the forces at play, Anand chats to Professor Emile Okal a seismologist from Northwestern University in the United States. Tsunami wave can move as fast as 800 kilometres an hour but, despite this, out at sea you might not notice it - but can the same be said for marine life? We follow the wave as it nears land and all that force is contracted and begins to show its might. Professor Suchana 'Apple' Chavanich from Chulalongkorn University, Thailand was one of the first people to swim off the Thai coast after the 2004 tsunami and remembers how coral reefs were battered. In Japan, after the 2011 Tohoku Earthquake and Tsunami as the water retracted it pulled with it tons and tons of debris into the water. The fishing communities of the Sanriku Coast lost almost everything, their equipment was destroyed and the water was heavily polluted. Anand meets Hiroshi Sato who set up the Sanriku Volunteer Divers, a team of people who dragged the debris out of the water. One of them was diver and journalist Bonnie Waycott who tells her story of witnesses the destruction first hand and trying to rescue the fishing industry with Hiroshi. Finally, we learnt that the effect of modern tsunamis carries far further than people might have imagined. On the west coast of the United States Professor Samuel Chan is an expert in invasive species at Oregon State University. He explains how modern infrastructure is contributing to some incredible migrations. Presenter: Anand Jagatia Producer: Tom Bonnett Editor: Ben MotleyPhoto: USA, California, Sonoma County, Bodega Bay, tsunami evacuation panel - stock photo Credit: Brigitte MERLE via Getty Images)

In your final moments, they say, you may walk down a tunnel of light. You might rise above your body, watching the scene below before passing into another world. Perhaps you’ll be met by glowing figures, see your life flash before your eyes, or feel a deep, unearthly calm. These are the stories of people who’ve reached the edge of death and returned. They’re not rare, nor random, and they have a name: near-death experiences. CrowdScience listener Steven in Chile first heard of them during a CPR class and wondered, are they fictitious? Psychologist Susan Blackmore once had an out-of-body experience as a student in Oxford, UK — floating above herself before soaring over the rooftops and dissolving into the universe. That single moment changed everything. She’s spent her career trying to understand what happened, and she believes such experiences are explainable. At the University of Michigan in the US, neuroscientist Professor Jimo Borjigin has done what few have dared: record the dying brain in action. Her studies show that even after the heart stops, the brain can produce powerful surges of coordinated activity, bursts that might explain the lights, the tunnels, and the sense of peace. She believes near-death experiences could become one of science’s most intriguing scientific frontiers for research into consciousness. At University College London in the UK, neuroscientist Dr Christopher Timmermann is exploring similar states using psychedelics, pushing the boundaries between self and oblivion to identify what induces a near-death experience and what we can learn about our consciousness along the way. Near death experiences, a paranormal mystery or explainable phenomenon? Presenter: Caroline Steel Producer: Harrison Lewis Editor: Ben Motley(Photo: Gap in the wall - stock photo Credit: peterschreiber.media via Getty Images)

For some they’re the stuff of nightmares, but many of us can’t get enough of horror films. For Halloween, CrowdScience investigates the science of why we enjoy films that scare the living daylights out of us. CrowdScience listener Maria from Taiwan is one of those people who would rather avoid frightening films, yet her husband loves them and is always trying to get her to watch with him. She wants to know why people like her husband are so drawn to horror films. To try and find out, presenter Anand Jagatia travels to the Recreational Fear Lab in Aarhus, Denmark, which is dedicated to understanding why people frighten themselves for fun. He meets the research lab’s directors Mathias Clasen and Marc Andersen who explain how horror and recreational fear could help us cope better with uncertainty, bond with those we are frightened beside, and perhaps even have some physical health benefits. They also take Anand to a haunted house, called Dystopia, which has used the Recreational Fear Lab’s research to become as terrifying as possible. And we hear from horror film music composer, Mark Korven, who creates tension and fear using an invention he calls ‘the apprehension engine’. He speaks to BBC Naturebang’s Becky Ripley who has been investigating sounds that scare us and their evolutionary origins. Presenter: Anand Jagatia Producer: Jonathan Blackwell (Photo: Couple watch horror movie with blanket to cover their heads. Credit: WC.GI via Getty Images)

We all know insects are important, but one CrowdScience listener worries that they don’t seem to have equal billing when it comes to human love and attention. In Scotland’s capital Edinburgh, listener Ruth loves to sit and listen to the birds, the bees and the hoverflies as they go about their daily chores. And it’s got her wondering why bees and butterflies seem to get all the conservation efforts. What do we need to do to protect butterflies as less beautiful caterpillars, and ladybirds as less glamorous larvae? Are people even aware that insects exist in multiple stages of a lifecycle, and that around the world, insect populations are facing perilous levels of decline. Presenter Alex Lathbridge is on a mission to identify the other unsung insect heroes. Along the way we meet Dr Caitlin Johnstone and Dr Nick Balfour at the Royal Botanic Gardens Edinburgh, who help listener Ruth find out about the lifestyles and lifecycles of hoverflies. We meet the midge that pollinates cocoa crops in Ghana, as well as Dr Tonya Lander from Oxford University and Dr Acheampong Atta-Boateng from the University of Arizona who have been studying them. And Marc Vaez-Olivera from the company Polyfly introduces us to the billions of hoverflies helping to double avocado yields in Spain. We also learn what we can all do to help keep insects in our gardens… even if that may involve sacrificing a cabbage or two. Presenter: Alex Lathbridge Producer: Marnie Chesterton Editor: Ben Motley(Photo: Caterpillar eating flowering plant with pink background - stock photo Credit: Raquel Lomas via Getty Images)

How would you record a special moment? Maybe you could take a photograph, film a little video, or record some audio. We have lots of ways of recording what life LOOKS and SOUNDS like, but is the same true for the other senses? What if you wanted to record the smells that greet you on entering your favourite restaurant? Or record the way your loved ones hand feels in yours? These are the questions on the mind of listener Aravind, from California in the USA. He wants to know if there are any ways of recording and reproducing sensory experiences like taste and smell, or physical touch. Anand Jagatia is on the case, and is smelling, tasting, and quite literally FEELING his way to the answer. From a multi-sensory movie experience in Valencia, Spain, to the fascinating history of the pioneers of ‘scented cinema’, through to the ground-breaking “haptic technology” which is enhancing the capabilities of our sense of touch. Both for us, and for the robots which do the jobs we don’t want to. Presenter: Anand Jagatia Producer: Emily Knight Editor: Ben Motley(Photo: Woman making ASMR sounds with microphone and perfume on yellow background, closeup - stock photo. Credit: Liudmila Chernetska via Getty Images)

Atoms are the building blocks of our world. Many have been around since right after the Big Bang created the universe nearly 14 billion years ago. And if life on Earth is made of atoms that are from all the way back then... will those atoms keep existing forever? That’s what CrowdScience Listener Rob in Australia would like to know. Caroline Steel investigates the immortality of atoms by travelling to CERN, the world’s largest particle physics laboratory located along the border of France and Switzerland. There, theoretical physicist Matthew McCullough explains whether the smallest atoms can decay or survive the test of time. Physicist Marco van Leeuwen from Nikhef, the National Particle Physics Laboratory in the Netherlands, gives Caroline a behind-the-scenes tour of the ALICE experiment and the Large Hadron Collider at CERN. She learns how atoms are smashed at incredibly high speeds, and whether that might spell the end of an atom. And all life on earth is made up of atoms, but how does a collection of tiny particles become a living being? Astrobiologist Betül Kaçar from the University of Wisconsin, Madison, breaks down how life works from an atomic point of view. Presenter: Caroline Steel Producer: Imaan Moin Editor: Ben Motley (Photo: Hands cupping a glowing atom in the studio - stock photo. Credit: Paper Boat Creative via Getty Images)

Listener Jude in Canada wants to know why some animals are black and white. Why do zebras risk being so stripy? Why do pandas have such distinct marking? And do they have something in common? Presenter Caroline visits Pairi Daiza, a zoo in Belgium. Together with her guide for the day, Johan Vreys, she looks at these weird and wonderful animals up close. First, she visits three zebras having breakfast. Ecologist Martin How from the University of Bristol explains his ingenious experiment involving horses with zebra blankets. Next on the tour is the giant panda which, according to Prof Tim Caro from the University of Bristol, looks at the way it does to camouflage in snowy forests in China. But there are many more animals to see, and many more reasons to be monochrome, including the penguin and its tuxedo-like colouration. Hannah Rowland, senior lecturer at the University of Liverpool explains that it might have more than just a single function. It turns out, scientific answers aren’t always black and white. Presenter: Caroline Steel Producer: Florian Bohr Editor: Ben Motley(Photo: The zebra was running gracefully running in the green water. Credit: Surasak Suwanmake/Getty Images)

Sometimes in science, when you try to answer one question it sparks even more questions. The CrowdScience inbox is a bulging example of that. We get tons of new questions every week and many of those are following up on episodes we’ve made. Sometimes you want us to go deeper into part of the answer, or sometimes a subject intrigues you so much that it inspires further questions about it. In this episode presenter Caroline Steel is on a mission to answer some of those questions. The CrowdScience episode How do fish survive in the deep ocean? led listener Ivor to wonder what sort of vision deep sea fish might have. On hand to answer that is Professor Lars Schmitz, Kravis Professor of Integrated Sciences: Biology, at Claremont McKenna College in the USA Sticking with vision, we also tackle a question inspired by the CrowdScience episode Do we all see the same colour? For years listener Catarina has wondered why her eyes appear to change colour. Professor Pirro Hysi, ophthalmologist at the University of Pittsburgh, sheds some light on that subject. In India, Rakesh listened to the CrowdScience episode Will the Earth ever lose its moon? and wondered about Jupiter’s many moons. The European Space Agency’s Ines Belgacem is working on a new mission to study Jupiter’s moons. She explains which of the giant planet’s ninety seven moons are ones for Rakesh to watch. We also hear how the episode Why can’t my dog live as long as me? caught the attention of listener Lisa... and her cat. She had us falling in love with the long history of falling cats and the scientists who study them. Caroline is joined by Professor Greg Gbur, physicist at the University of North Carolina, Charlotte in the USA and author of Falling Felines and Fundamental Physics. Could this episode of follow up questions lead to an episode investigating the follow up questions to these follow up questions? Have a listen and, who knows, maybe you’ll find yourself inspired to email crowdscience@bbc.co.uk Presenter: Caroline Steel Producer: Tom Bonnett Editor: Ben Motley(Photo: Innovation and new ideas lightbulb concept with Question Mark - stock photo Credit: Olemedia via Getty Images)

CrowdScience listener David is a bird whisperer. On his family farm in Guinea, he would mimic the call of the black-headed weaver. He could replicate it so well that the birds would fly in close, curious to find out who was calling. David has been wondering if he was actually communicating with the weaver. In the foothills of the Austrian Alps is a research hotspot with a curious history. It was here that a scientist first began studying birds in their natural environment. That work continues today with Andrew Katsis from the University of Vienna, who knows the local flock of greylag geese by name. His research shows that animals aren’t just anonymous members of a group, they have personalities, relationships, and the ability to recognise one another. But what else do birds know? Thomas Bugnyar, professor of social behaviour and animal cognition, spends his time trying to get inside the mind of ravens. His work suggests they can understand their surroundings, make rational decisions, and even solve complex problems. Plus, we meet Ellie, a cockatoo with the ability to use a touchscreen computer to “talk.” She has a working vocabulary of more than 1,500 words. And when she presses a button, it would appear she is not just pecking at random, she is choosing purposefully, responding in ways that suggest birds may not only understand us, but communicate back. Presenter: Caroline Steel Producer: Minnie Harrop and Harrison Lewis Series producer: Ben Motley(Photo: Close up of Greylag goose with blue background Credit: Harrison Lewis, BBC)

CrowdScience listener Kerry started thinking about his sentimental attachment to his possessions when he began sorting through an old trunk, full of objects from his past. He wants to know why we get so attached to things that often have no use anymore and why it’s so hard to give them away. Anand Jagatia investigates why the objects we accumulate during our lives mean so much to us. He talks to psychologists Mary Dozier and Melissa Norberg and finds out that our possessions offer stability and comfort from the earliest age. That keepsake you brought home from your holiday may also stir memories about days gone by - and that’s one reason why we may find it hard to part with the things we own, because they help us to access our emotions. And the items we collect through our lives can come to represent our identity too. Anand visits the Museum of Broken Relationships in Zagreb, Croatia, where people from all over the world have donated possessions from relationships that ended, whether romantic or family, and discovers that sentimental attachment is universal. Presenter Anand Jagatia Producers Jo Glanville and Imaan Moin Editor Ben Motley(Photo: Memories box in book shelf - Credit: Jan Hakan Dahlstrom via Getty Images)

Milk: drink a lot of it and we’ll grow big and tall with strong bones. That’s what many people are told as children, but just how true is this accepted wisdom? CrowdScience listener JJ in Singapore is sceptical. He wants to live a healthy life for as long as possible, and he’s wondering whether drinking cow’s milk will help or hinder him on this mission. All mammals produce milk, and our mother’s milk is our very first drink as babies. So what actually is the white stuff? Mary Fewtrell, professor of paediatric nutrition at UCL, gives presenter Chhavi Sachdev the lowdown on just how fundamental breastmilk is to us all. But are we meant to continue drinking milk from other animals once we grow up? This behaviour of ours is rare among mammals… so Christina Warinner, professor of evolutionary biology at Harvard University, tells us when in our history cow’s milk entered our diet, and how we even came to be able to digest it. And is there any truth in the accepted wisdom that cow’s milk will give us stronger bones? Karl Michaelsson, professor of medical epidemiology at Uppsala University, has researched just this – and the answer isn’t what you’d expect. Karl helps Chhavi sift through the complex evidence to see whether milk is actually any good for us.Presenter: Chhavi Sachdev Producer: Sophie Ormiston Editor: Ben Motley(Photo:Lady milking cow, Nadiad, Gujarat, India)

What will remain of us hundreds of millions of years from now? And how can we be so certain that we are the first technologically advanced species on Earth?These unsettling questions have been haunting listener Steve. If fossils can be lost to deep time through erosion and subduction into the Earth’s mantle, how would anyone — or anything — ever know that we had been here? And if an earlier species had built a civilization that rose and fell, would we even be able to find traces of it?To investigate, CrowdScience presenter Caroline Steel speaks to the scientists trying to answer these questions, while producer Sam Baker goes fossil hunting on the Jurassic Coast in the UK. Caroline speaks with astrophysicist Adam Frank at the University of Rochester in the US, who along with NASA scientist Gavin Schmidt developed the Silurian hypothesis – the idea that if an advanced species had existed deep in Earth’s past, they might have vanished without leaving a trace. But palaeontologists Jan Zalasiewicz and Sarah Gabbott from the University of Leicester in the UK argue that humans are already leaving an indelible mark in the form the chemical and material fingerprints we’re pressing into Earth’s crust. They contend that the ‘technofossils’ we are producing will last a very long time indeed.Along the way, Caroline and producer Sam discover just how rare fossils really are, how even the tiniest particles of pollution will give us away to far-future explorers, and why car parks might be our ultimate legacy. What they find is at once unsettling and oddly comforting: humanity could be fleeting, but our impact probably won’t be.Could we really have missed evidence of an ancient civilization? And what strange clues will we leave behind for whoever, or whatever, comes next? We explore Earth’s geological memory to find out.Presenter: Caroline Steel Producer: Sam Baker Editor: Ben Motley(Photo: Old phone embedded in concrete layer with defocused landscape background Credit: Petra Richli Via Getty Images)

Camouflage isn't just for chameleons! Military forces around the world deck their soldiers out in those distinctive green and brown uniforms, to give them the best chance of staying safe, and remaining undetected. But how do they work? Why do they look so different from country to country? And why do you still see soldiers wearing it in the city, when it can't possibly work as camouflage? These are the questions in the mind of Crowdscience listener Paul, in Uganda. In his home of Kampala he often sees soldiers on patrol. As a botanist, he's fascinated by the nature-inspired designs, and he wants to know how they came to be. So Alex Lathbridge sets off to find out. At Camolab at the University of Bristol, Laszlo Talas talks Alex through the history of battle-dress. There have been some extraordinary designs over the years, some of them quite beautiful in their way, and many with hidden easter eggs printed into the design! In a patch of forest on the outskirts of Prague, Alex gets to try some of the latest gear out for himself. Fully kitted out in ghillie suit, camouflage chaps, face mask and goggles, he tries to disappear into tue background. With the help of 4M Tactical, the company who manufacture a cloak currently in use in Ukraine. It has the power to make you invisible, not just in the visible spectrum, but in the infrared too. With high tech sensors and infrared cameras now a staple of the modern battlefield, clothes like this are becoming essential. Not all camouflage technology belongs to the military. Futuristic clothing company Vollebak in London are using 'the fabrics of the future' to design high tech streetwear for savvy 21st century urban warriors. Founder Steve Tindall shows Alex their prototype Thermal Camo Jacket, which uses hundreds of layers of graphene to give the illusion of heat, or cold. Steve says that hiding in plain sight is less about concealing yourself from human eyes, and more about avoiding the pervasive sensors and constant surveillance that are increasingly a feature of urban living. Meanwhile in Sweden, they're taking the inspiration from chameleons more literally. Hans Karis, deputy research director of the Swedish defence institute FOI, introduces Alex to their Adaptive Camouflage, interwoven with a network of tiny coloured LEDs to change colour at will. It's not on the market yet, but perhaps chameleon soldiers will be a thing of the future. Presented by Alex Lathbridge Produced by Emily Knight(Photo: Thermal imaging of people in the woods)

When listener Rob from Devon, UK, heard of a newly detected planet light years away, he was struck by the sheer scale the light must travel to reach us here on Earth. It got him wondering: How long does light last? What is the oldest light we have ever observed? And does light ever die? To find out, presenter Anand Jagatia calls on some of the brightest minds in astronomy and physics. Astronomer Matthew Middleton from the University of Southampton explains how scientists still struggle to define exactly what light is. What we do know is that light comes in many forms, and choosing the right kind can peel back the cosmic curtain, revealing the universe’s deepest and darkest secrets. That knowledge will prove vital in Anand’s search for the oldest light ever observed. At the European Southern Observatory in Chile, staff astronomer Pascale Hibon gives Anand a behind-the-scenes look at the Very Large Telescope, one of the most advanced optical instruments on Earth, perfectly placed under some of the clearest skies on the planet. Light from the objects Pascale studies has often travelled for billions of years, making her images snapshots of the distant past.If light has crossed the vastness of the universe to reach us, it must be unimaginably ancient. But what will become of it in the far future? Could we trap it and preserve it forever? Miles Padgett at the University of Glasgow, has spent his career trying to pin it down. As Anand discovers, physics can be more philosophical than you might expect. Presenter: Anand Jagatia Producer: Harrison Lewis Editor: Ilan Goodman(Photo: An area of deep space with thousands of galaxies in various shapes and sizes on a black background. Most are circles or ovals, with a few spirals. Credit:G. Östlin, P. G. Perez-Gonzalez, J. Melinder, the Jades collaboration, M. Zamani/ESA/Webb, Nasa and CSA)

CrowdScience listener Rit, from Pune in India, is staring out of his window at the falling rain. It’s been pouring for four days now, and shows no sign of stopping. The laundry is piling up, all his shoes are wet, and he’s worried about the effect it’s having on the environment, and on agriculture. When it rains like this, the animals suffer, and the crops are destroyed. Cloud seeding and Weather Engineering are hot topics right now, and can bring the rain to places that need it. But Rit wants to know whether we can artificially stop the pouring rain, especially in an emergency. Following the devastating floods in Texas, it’s clearly not just a problem for countries with a monsoon season. Presenter Chhavi Sachdev is also sitting in a downpour at home in Mumbai. She dons her rain jacket and rubber boots to try and find out whether science can help Rit with his question. From controlling the clouds in India, to bringing rain to the deserts of the UAE, to firing high-powered lasers into the skies above Geneva, we find out what weather engineering is really capable of. With thanks to: Dr Thara Prabhakaran, from the Indian Institute of Tropical Meteorology Alya Al Mazroui, Director of the UAE Research Program for Rain Enhancement Science Jean-Pierre Wolf, Applied Physics Department of the University of Geneva Presenter: Chhavi Sachdev Producer: Emily Knight Series Producer: Ben Motley(Image: Girl carrying umbrella while standing on road against trees during rainfall. Credit: Cavan Images/Getty Images)