Could you survive an eternal winter? Or is endless summer sun a more appealing prospect? Lots of us are grateful for the seasonal changes that shape the world around us, but this week Hannah and Dara are asking what life would look like without the axial tilt that brings each hemisphere closer and further away from the sun as the seasons change each year. Listener Andrew from Melbourne wants to know what would happen if the planet stood perfectly upright, no lean, no tilt, no seasons. But what else could happen? Is Earth?s 23-degree slant the cosmic fluke that made life possible? To find out, Hannah and explore how losing the tilt reshapes climate, ecosystems, evolution and maybe even the fate of the dinosaurs.

You can send your everyday mysteries for the team to investigate to: [email protected] Contributors Dr Robin Smith - Climate modelling researcher at the University of Reading Professor Rebecca Kilner - Evolutionary Biologist and Head of the Department of Zoology at Cambridge Professor Amaury Triaud - Professor of Exoplanetology at the University of Birmingham Aidan McGivern - Meteorologist and Senior weather presenter at the MET Office

Producer: Emily Bird Executive Producer: Sasha Feachem A BBC Studios Production

Could immortality ever be possible for humans? It sounds like something from a sci-fi movie, but floating in oceans around the world is a tiny, transparent jellyfish that could hold the answer...

Turritopsis dohrnii, known as 'the immortal jellyfish', isn?t immortal in the true sense of word - it can die - but it has a nifty way of avoiding that fate. In times of stress, this miniscule jelly can biologically reverse its aging process, reverting from 'medusa' (adult jellyfish) to a juvenile form and starting its life-cycle again; potentially ad infinitum.

Abilities like these could hold the key to - if not exactly 'immortality', then at least regenerative or long-life treatments for humans in future. But of course there's a catch: these extremely delicate jellyfish can still easily die from predation, disease, or environmental threats and are extremely difficult to keep healthy in a lab environment.

Hannah and Dara hear about new technology that could change the way we study immortal jellyfish, and discover various other super-abilities in the animal kingdom that could help in our quest for healthier, longer lives.

Contributors: - Miranda Lowe, Principal Curator of Crustacea and Cnidaria at London?s Natural History Museum - Alex Cagan, Assistant Professor in the Department of Genetics, Department of Pathology and Department of Vet Medicine at the University of Cambridge - Maria Pia Miglietta, Associate Professor of Marine Biology at Texas A&M University in Galveston - Nicole Xu, Assistant Professor of Mechanical Engineering, Robotics and Biomedical Engineering at the University of Colorado, Boulder

Producer: Lucy Taylor Executive Producer: Sasha Feachem A BBC Studios Production

Space: the final frontier, a deep dark realm full of questions and mysteries - many of which science can't yet satisfactorily answer. But that won't stop the Curious Cases team!

In a special edition recorded in front of an audience at the BBC Radio Theatre in London, Hannah Fry and Dara Ó Briain team up with a panel of guests who know their way around the universe: presenters from the world's longest running science TV show, The Sky At Night.

With the intergalactic expertise of George?Dransfield, Chris?Lintott and Maggie Aderin-Pocock, Hannah and Dara tackle a slew of space-related questions put forward by the listeners - exploring topics ranging from the sound of stars and the shape of the universe, to the search for alien life.

To submit your question to the Curious Cases team, please email: [email protected]

SPACE AUDIO CLIPS:

- Maggie's Choice: In 2005, the European Space Agency's Huygens probe descended to the surface of Saturn's moon Titan. Microphones aboard Huygens recorded the sounds of descent and landing, then The Planetary Society and scientists at the University of California helped ESA process the audio. CREDIT: European Space Agency (Huygens probe) / HASI-PWA Team (instrument and data) / The Planetary Society (processing)

- George's Choice: The black hole at the centre of the Perseus galaxy cluster has been associated with sound for years, since astronomers discovered that pressure waves sent out by the black hole caused ripples in the cluster's hot gas that could be translated into a note. This new sonification was released for NASA's Black Hole Week in 2022. CREDIT: NASA

- Chris's Choice: In 2023, the Planck space telescope picked up echoes left by soundwaves that travelled through the early Universe. This primordial hum was then translated into frequencies we can hear. CREDIT: NASA

Producer: Lucy Taylor Executive Producer: Alexandra Feachem A BBC Studios Production

Whether you?re stuck in traffic, waiting at the airport whilst delay after delay is announced or just really missing someone far away, a lot of us have probably wished we could teleport. But is this superpower the stuff of science fiction? Or could it, one day, become a reality?

Listener Faith wants to know whether Star Trek?s Transporter could ever deconstruct and reconstruct humans in the real world, and it turns out quantum physics holds some tantalising potential for this seemingly impossible task. To search for answers Hannah and Dara dive down the quantum rabbit hole, exploring entanglement, superposition, and trying on some very special socks.

Contributors Ivette Fuentes - Professor of Quantum Physics at University of Southampton Winfried Hensinger - Professor of Quantum Technologies at the University of Sussex Helen Beebee - Professor of the Philosophy of Science at the University of Leeds

Producer: Emily Bird Executive Producer: Sasha Feachem A BBC Studios Production

Cold and flu season is well and truly upon us, and whilst most of us are busy bemoaning the pesky viruses behind our sniffles and chesty coughs ? one of our listeners has other ideas. Elizabeth wants to know whether we?re too hard on these oft-maligned microbes? We?ve all heard that some bacteria can be good for us, but what about viruses? Could they have a softer side too? Hannah and Dara explore the virome, from prehistoric placental proteins to ultra-precise disease fighting phages to find out if Viruses truly are the villains of the microscopic world or whether they just need a better PR team.

Contributors Jonathan Ball - Professor of Molecular Virology at the Liverpool School of Tropical Medicine. Martha Clokie - Professor of Microbiology at the University of Leicester. Marylin Roosinck - Professor Emeritus of Microbiology at Penn State University US.

Producer: Emily Bird Executive Producer: Sasha Feachem A BBC Studios Production

It has been said that you can't start a fire without a spark, but as Hannah and Dara are about to discover, that's not true!

Welcome to the fiery phenomenon of spontaneous combustion, when something can ignite all on its own: no matches, no sparks, no external flame. It happens when certain materials heat themselves up internally through chemical or biological reactions, and if that carried on unchecked and the material gets hot enough, it can eventually ignite itself.

This process can occur in various everyday items such as piles of hay or grass clippings, oily rags and in certain instances lithium batteries; but there are also several useful chemical substances that autoignite when they come into contact with air - as Hannah, Dara and a wary BBC fire officer witness in the studio...

So how can we stop things regularly bursting into flames? How scared should we be about oiling floorboards and our increasingly battery-powered life? And is spontaneous human combustion really a thing? Our investigators are on the case.

To submit your question to the Curious Cases team, please email: [email protected]

Contributors: - Andrea Sella, Professor of inorganic chemistry at University College London - Emanuel ?Big Manny? Wallace, former science teacher now a science content creator - Matt Oakley, fire investigations officer at Surrey Fire and Rescue Service - Roger Byard, Emeritus Professor of pathology at the University of Adelaide and a senior specialist forensic pathologist at Forensic Science SA (FSSA)

Producer: Lucy Taylor Executive Producer: Alexandra Feachem

A BBC Studios Production

Are you a lucky person? Do the cards just fall well for you? Whether it's always finding a parking spot when you need one or chance encounters that change your life's trajectory for the better, some people seem to have more luck than others. Hannah and Dara explore the world of probability and psychology to figure out if some people are luckier than others, and if there's anything we can do to turn things around.

You can send your everyday mysteries for the team to investigate to: [email protected]

Contributors David Spiegelhalter - Emeritus Professor of Statistics in the Centre for Mathematical Sciences at the University of Cambridge Richard Wiseman - Professor of the Public Understanding of Psychology University of Hertfordshire Maia Young - Professor of Organization and Management at UC Irvine, California US Edward Oldfield

Producer: Emily Bird Executive Producer: Sasha Feachem A BBC Studios Production

It turns out that the whole world wobbles. Everything has a natural frequency - the rate at which it moves when disturbed - be it a cup of tea, a building or a human organ.

Even more incredibly, if an external force matches an object's natural frequency, it causes it to absorb that energy and vibrate with increasingly large waves; and that can have consequences, from helping a spider find its lunch to making a bridge collapse.

On the trail of good and bad vibes and everything in between, Hannah and Dara investigate whether the famous 1940 collapse of the Tacoma Narrows Bridge in the USA was really down to resonance, explore examples of resonance in nature, and find out what this mysterious vibration can do to the human body: from the pressures of repetitive tractor-driving, to absorbing the reverberations of certain instruments...

To submit your question to the Curious Cases team, please email: [email protected]

Contributors: - Helen Czerski, Professor of Physics at University College London - Wanda Lewis, Emeritus Professor of Civil Engineering at Warwick University - Phillip Moxley, Senior Research Associate at the University of Southampton - Sana Bokhari, sound therapy practitioner

Producers: Lucy Taylor & Emily Bird Executive Producer: Alexandra Feachem

A BBC Studios Audio Production

We can all picture a crab, but did you know that nature has reinvented those claw clicking, sideways scuttling crustaceans at least five separate times? In recent years the internet has run wild with the idea that crabs are the ultimate life-form, and that even humans might one day end up with pincers too. But is there any truth behind the memes? Hannah and Dara scale the tangled tree of life and tackle taxonomy to figure out if ?crab? really is evolution?s favourite shape. Exploring coconut to spanner, ghost to hermit, soldier to spider they learn how to tell the ?true? crabs from the impostors.

You can send your everyday mysteries for the team to investigate to: [email protected]

Contributors Dr Joanna Wolfe ? Evolutionary Biologist, Harvard University and UC Santa Barbara Professor Matthew Wills - Professor of Evolutionary Paleobiology, University of Bath Ned Suesat-Williams ? Director of the Crab Museum, Margate

Producer: Emily Bird Executive Producer: Sasha Feachem A BBC Studios Production

Hannah Fry and Dara Ó Briain return to Curious Cases HQ for a brand-new series. And curios, there?s a lot to unpack! Coming soon to BBC Sounds.

The term 'bird brain' might suggest our feathered friends are stupid, but Hannah and Dara learn it's completely untrue. They play hide and seek with a raven called Bran, and hear how his behaviour changes depending on his mood. Corvid expert Nicola Clayton explains these creatures are actually cleverer than the average 8-year-old, and can learn how to choose specific tools for different scenarios. And neurobiologist Andreas Nieder tells them that while crows evolved totally different brains from humans - 300,000 years apart - they might just be capable of the same type of intelligence.

Contributors:

Bran the raven Lloyd Buck, bird handler Professor Nicky Clayton, University of Cambridge Professor Andreas Nieder, University of Tubingen

Producer: Marijke Peters Executive Producer: Alexandra Feachem

A BBC Studios Audio Production

Could you ever trade memories with someone else? Fancy downloading the experience of landing on the moon, winning an Oscar or performing at Glastonbury? Listener Adam wants to know, and Hannah Fry and Dara Ó Briain are on the case.

With expert insights from Professor Chris French and Professor Amy Milton, they dive into the mind?s tendency to blur the lines between reality and imagination - often embellishing, distorting, or downright making stuff up.

Discover how memory conformity makes us ?see? things like spoons being bent by paranormal forces, how scientists can implant artificial memories in mice, and hear Al Hopwood?s hilariously vivid tales of things that definitely never happened. Chris even spills the secrets of how to deliberately plant false memories in others (don?t try this at home!).

From rewiring trauma to curing phobias, the potential of memory manipulation is both exciting and unnervingly sci-fi. Prepare to question everything you think you remember.

Contributors:

Amy Milton - Professor of Behavioural Neuroscience at the University of Cambridge Chris French - Professor of Anomalistic Psychology at Goldsmiths University Al Hopwood - Artist, writer and curator

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Can you slow down time by hurtling through space at breakneck speed? Could listener Saskia?s friend - currently one year older - end up the same age as her if he went fast enough? It sounds bananas, but it?s all part of Einstein?s mind-warping theory of relativity.

With expert copilots Professor Sean Carroll and Dr. Katie Clough, Hannah Fry and Dara Ó Briain embark on a cosmic roller coaster through space and time. They uncover why GPS satellites - whizzing around Earth at 14,000 km/h - need to account for time bending, why penthouse dwellers age faster than those on the ground floor, and, most importantly, why clowns on trains might just hold the key to understanding modern physics.

Contributors:

Katy Clough - Research Fellow at Queen Mary University of London Sean Carroll - Professor of Natural Philosophy at Johns Hopkins University Peter Buist - Manager of the Galileo Reference Centre Richard Dyer - PhD student at the University of Cambridge

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

How big can animals really get before they collapse under their own weight or run out of snacks? Could a 12-foot comedian survive their first punchline without snapping in half? Listener Andrew sends Hannah and Dara on a deep dive into the science of supersized species.

With evolutionary biologists Ben Garrod and Tori Herridge as their guides, they explore the quirky rules of scaling: why giant bones need air pockets, how pressure stockings aren?t just stylish but essential, and why massive creatures have to choose between inefficient chewing or letting dinner ferment in their cavernous stomachs.

Discover why scaling up a mouse would turn it into a blood-boiling disaster and learn the curious logic behind whether the meat bear should eat the two meat dogs, or vice versa (it?s a maths thing?you?ll have to listen). Oh, and here?s the weird constant: whether you?re a mouse or an elephant, everyone takes roughly the same time to pee!

Join Hannah and Dara for a colossal romp through the wild world of ancient giants and the gross super blobs of the (possible) future.

Contributors:

Tori Herridge - Senior Lecturer in evolutionary biology at the University of Sheffield Ben Garrod - Professor of Evolutionary Biology and Science Engagement at the University of East Anglia Martin Sander - Professor of Palaeontology at the University of Bonn

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Think of a shark and you'll probably conjure up images of Jaws, but it turns out their skin is also covered in tiny teeth. Hannah and Dara investigate the incredible properties of these so-called dermal denticles, to find out whether they could be replicated at a nanoscale to increase vehicle speeds. They learn that while sharks might look like they have beautifully sleek surfaces, up close their skin is covered in something extremely rough and textured, a property that helps them swim up to 12 percent faster. And it's already inspiring airlines to design ultra-thin films that can reduce drag and increase efficiency.

Contributors

Dr Jess Wade Professor Manish Tiwari

Producer: Marijke Peters Executive Producer: Sasha Feachem

A BBC Studios Audio Production

Why do we giggle, snort, and bust a gut laughing? Is it just humans being weird, does it serve some higher function or do other animals crack up too? And, okay, Dara is a comedian, but has he ever really made anyone laugh, like properly?

With help from Professor Greg Bryant and Professor Sophie Scott, they dive into the science of LOLs, exploring how laughter bonds us, eases stress, and even spices up flirting. They uncover the difference between genuine belly laughs and those polite chuckles that pepper everyday interactions.

Contributors:

Sophie Scott - Professor of Cognitive Neuroscience at UCL Greg Bryant - Professor of Communication at UCLA Betty La France - Professor or Communication, Northern Illinois University

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Ever wondered why some people are mosquito magnets and other people barely get bitten? Hannah and Dara grapple with the question of whether these insects are evil or genius, discovering how they?re experts at finding blood when they?re hungry, even using a specially designed syringe to suck it out. But when Professor Leslie Vosshall tells them some people are more than 100 times likely to be attacked than others, the pair start wondering which one of them is more attractive? So they put the science to the test, and reluctantly agree to send their stinky socks to Professor Sarah Reece. She reveals that one of them smells extra special to these annoying little animals, possibly because of their cheesy feet. But can you guess who?

Contributors: Professor Sarah Reece Professor Leslie Vosshall Professor John Pickett

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

The team test the theory that you can use the weather to predict pain, separating science fact from fiction. It's an area with a huge amount of conflicting research, but one man who has investigated this is Professor Will Dixon, who explains that low pressure could be causing people's joints to ache more. Dara and Hannah are intrigued to hear our genes may also be responding to changes in temperature and hear how we might be pre-programmed to produce more inflammation during wintertime to fight off bugs - which has the unfortunate side effect of making other some conditions worse. But don't despair! The pair find out 21 degrees is the optimum temperature for health and wellbeing - a perfect English summer day.

Contributors:

Dr Chris Wallace Professor Will Dixon Professor Trevor Professor Trevor Harley

Producer: Marijke Peters Executive Producer: Alexandra Feachem

A BBC Studios Audio Production

From mouldy bread to athlete?s foot, fungi don?t exactly scream ?home improvement.? But what if this misunderstood kingdom is the secret to the sustainable materials of the future?

Listener Alexis - definitely not a gnome - wants to know how much of our homes we could build with fungi. Professor Katie Field describes how the mushroom is the just tip of the iceberg - it?s the network of thread-like filaments called mycelium where fungi really do their best work. Architect Phil Ayers explains how fungi, like yeast in bread, can bind waste products into firm, MDF-like blocks. And while we?re not constructing skyscrapers with mushrooms just yet, it turns out fungi-based materials are already making waves in interior design. Think sound-absorbing wall panels or insulation that?s both eco-friendly and chic.

And here?s a cool one: mushroom leather! Using discarded stalks from mushroom farms, one company is crafting strong, flexible material for trainers, handbags, and even car dashboards. Move over, cows - mushrooms are pushing their way up.

Oh, and NASA? They?re dreaming big with fungi too - to grow habitats in space. From mould...to the moon!

Contributors:

Katie Field - Professor of Plant-Soil Processes at the University of Sheffield Phil Ayres - Professor of Biohybrid Architecture at the Royal Danish Academy Patrick Baptista Pinto - co-founder of Really Clever Maurizio Montalti - Co-founder and Chief Mycelium Officer of SQIM / MOGU Lynn Rothschild - Senior Research Scientist at NASA Ames research centre

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

What happens in your brain when Cupid?s arrow strikes? As a teenager, Alison developed an intense crush on George Harrison from the Beatles. But, she wants to know, why do we develop these feelings for pop stars we?ve never actually met? And what potent swirl of neurochemistry drives those fierce emotions?

With neuroscientist Dr. Dean Burnett and evolutionary anthropologist Dr. Anna Machin as their guides, Hannah and Dara investigate everything from the brain?s chemical fireworks during a crush to the evolutionary perks of love and bonding. Along the way, they dissect teenage infatuations, lifelong love affairs with football teams, and why love can feel as addictive as heroin.

There?s even a guest appearance from two cute rodents: the monogamous prairie voles and their more, shall we say, commitment-phobic cousins, the montane voles, who gave us early clues about the role of the ?cuddle? hormone oxytocin.

Whether you're a hopeless romantic or a hard-nosed skeptic, prepare to fall head over heels for the science of love.

Contributors:

Dr Anna Machin - evolutionary anthropologist and author of Why We Love Dr Dean Burnett - honorary research fellow at Cardiff Psychology School, author of The Idiot Brain and The Happy Brain. Carmine Pariante - Professor of Biological Psychiatry at King?s College London

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Hannah and Dara tackle a disarmingly simple question: is anything in the universe truly invisible? After ruling out mysterious Nordic spirits and ?Dara?s ire?, our curious duo start to track down the invisible waves all around them. Including, it turns out, some which are emanating from their VERY OWN FACES! An infrared camera reveals Hannah?s nose as a particular hotspot.

Turning their gaze to bigger things, they wonder: what does our own galaxy look like when viewed in this invisible spectrum? Infrared reveals vast loops and whorls of dust and gas - gigantic structures otherwise totally hidden. But there are even cooler surprises. Ever wondered what an X-ray of the universe looks like? Turns out it?s a sparkly map of white-hot black holes!

Back on earth, the discussion turns to ways of making objects disappear by bending light in tricksy ways. But why is the fancy science of ?metamaterials? still struggling to make a proper invisibility cloak? Sorry, Harry Potter fans.

In the end, our physicists reveal a universe bursting with even more elusive, even more mysterious stuff: dark matter and dark energy. Prepare to see the unseen in a whole new light!

Contributors:

Matthew Bothwell - the Public Astronomer at the University of Cambridge and author of The Invisible Universe Andrew Pontzen - Professor of Physics at Durham University Mitch Kenney - Assistant Professor in metamaterials at the University of Nottingham

Producer: Ilan Goodman Executive Producer: Sasha Feachem A BBC Studios Audio Production

For any of you who have ever told a porkie pie, don't worry, this week we hear why we all do it... and discover that deception is actually good for social bonding. From the red squirrels who cry wolf to scare off the competition, to kids who look you in the eye as they tell bare faced lies, this is a behaviour that occurs across all species. And one man who's particularly good at it is Traitors contestant Paul Gorton who reveals he felt absolutely no guilt about his tv trickery. But it seems that while we're masters at telling tall stories, we're terrible at detecting them, because we've all been focusing on completely the wrong cues.

Contributors:

Paul Gorton Professor Richard Wiseman Professor Sophie van der Zee

Producer: Marijke Peters Executive Producer: Alexandra Feachem

A BBC Studios Audio Production

?Diamonds are nonsense!? Hannah boldly proclaimed in a previous episode. But listener Guy is a diamond enthusiast, and he and his diamond-loving pals were NOT OKAY WITH THIS. He demanded we re-open the case, and here we are...

SO in this glittering showdown, Dara is on a quest to flip Hannah?s perspective from ?meh? to ?marvelous.? And for Hannah, some uncomfortable facts soon emerge. It turns out that diamonds are much more than just overpriced bling. They're the secret ingredient in all sorts of high-tech gadgets with a whole arsenal of little-known superpowers.

Enter electrochemist Julie Macpherson, who blows Hannah?s mind by showing how diamonds can slice through ice like butter, thanks to their unmatched ability to conduct heat. Not impressed yet? Physicist Mark Newton makes a diamond glow in the dark, using nothing but his phone flashlight.

And that?s just to start! These ultra-robust gems can scrub nasty chemicals from water, serve as supercharged electrodes, and even reveal deep-earth secrets locked away for billions of years.

By the end of this episode, will Hannah finally admit diamonds are forever cool?

Contributors:

Charlie Bexfield - Gemmologist and diamond specialist Julie MacPherson - Professor of Chemistry at the University of Warwick Mark Newton - Professor of Physics at the University of Warwick Grahame Pearson - Professor of Earth Sciences from the University of Alberta

Producer: Ilan Goodman Executive Producer: Sasha Feachem A BBC Studios Audio Production

Hannah Fry and Dara Ó Briain return to tackle listener's questions with the power of science!

The buzz of a fly hovering just above your head has got to be one of the most irritating sounds around, but this week we try to work out just how fast they could be flying. Could a claim horseflies reach speeds of up to 90 mph possibly be true, and Dara wants to know if this is what makes them so difficult to swat?

Entomologist Erica McAlister is better known as the ?fly lady? and speaks up in defence of these tiny creatures, explaining there are 7,000 known species in the UK alone. Which makes it all the more shocking there are several that don?t have wings.

For Professor Graham Taylor the question of speed comes down to a simple calculation, and the team try to work out whether a horsefly beats its wings fast enough relative to its size to travel so rapidly. He explains horseflies aren't clever, but scientists are interested in their simple brains and are studying them to use as models for drones and mini robots.

Contributors:

Dr Erica McAlister, Natural History Museum Professor Graham Taylor, Oxford University

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Anyone who has ever done a long car journey with kids will be familiar with the idea of being bored to death ? but can this feeling really be fatal?

Hannah and Dara hear about a club where members count roundabouts and collect milk bottle tops, but boredom expert Wijnand van Tilburg explains these dull-sounding hobbies might actually have mental health benefits. He explains that science and comedy are stereotypically both seen as exciting subjects but warns them their chat about Venn diagrams might tip the balance the other way.

Mind-wandering specialist Mike Esterman reveals why we're rubbish at staying on task when there are more rewarding things to do, and sets the pair a challenge to play a computer game that distracts them with pictures of cute babies and fluffy animals.

Contributors:

Dr Wijnand van Tilburg: University of Essex Dr Mike Esterman: Boston Attention and Learning Lab

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

When you die, would you want to be frozen so that one day you might be brought back to life? Listener Elspeth wants to know if that?s even possible. So Hannah and Dara embark on a quest to explore the chiling science of ?cryobiology?: preserving living things at really low temperatures.

It turns out there are already thousands of people alive who were once suspended in antifreeze and stored in liquid nitrogen - when they were just a small clump of cells! There?s even a frog which can turn into a ?frogsicle? for months on end. But re-animating full size humans is a challenge no one has solved?yet. Will some miraculous nanotechnology of a distant future solve the problem?

Contributors:

Professor João Pedro de Magalhães: University of Birmingham Hayley Campbell: Author and broadcaster Professor Joyce Harper: UCL Dr Hanane Hadj-Moussa: The Babraham Institute, Cambridge Garrett Smyth: Cryonics UK

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Wake up! It?s time for a dreamy new episode of Curious Cases all about the science of sleepwalking.

Listener Abigail has done some strange things in her sleep, from taking all the pictures off the wall, to searching for Turkish language courses. And she wants to know: WHY IS THIS HAPPENING?

It turns out Abigail is not alone. Hannah and Dara hear weird and wonderful stories of extreme sleepwalkers - from the lady who went on midnight motorbike excursions, to the artist who does all his best work while asleep. They delve into the neuroscience to find out how you can remain in deep sleep while walking, talking or even peeing in your mum's shopping basket. They learn about some cutting edge research where the participants were sleep deprived and then half-woken with scary sounds, and they zero in on the key triggers, from a boozy night out to a squeaky bed.

Contributors Professor Russell Foster: University of Oxford. Professor Guy Leschziner: King?s College London and Guys? and St Thomas? hospital Lee Hadwin: the sleep artist Professor Francesca Siclari: The Netherlands Institute for Neuroscience

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Fruit-powered batteries are the ultimate school science experiment, but they?re normally used to power a pocket calculator. This week?s listener wants to know if they could do more, and sends the team on a quest to discover whether they could used to send a rocket into space?

Professor Saiful Islam is the Guinness World Record holder for the highest voltage from a fruit-based battery, but disappoints the team when he reveals they produce very little power. He used 3,000 of them and only managed a measly 2 Watts. Given that spaceships are famously difficult to get off the ground, it seems a lemon battery might just fail the acid test.

Author Randall Munroe is undeterred and suggests alternative ways to get energy from citrus, including burying them to make oil. Then the team discuss the pros and cons of switching to a lemon-based diet.

For battery expert Paul Shearing, all this raises a serious question, about how we will power the planes of the future. He suggests solar power could play a part in short-haul flights and discusses some of the exciting battery materials being tested today.

Contributors:

Randall Munroe, author Professor Paul Shearing, Oxford University Professor Saiful Islam, Oxford University

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Are you more of a rhino or a kitten? More like a tortoise or a hare? Listener Ivy wants to know what makes a good athlete and so Hannah and Dara tackle the science of sport.

Our curious duo get to grips with the rigours of training tailored for endurance events vs those based on more explosive bursts of activity. They consider the contribution of genetics, fast vs slow twitch muscle fibres, the unique advantage of Michael Phelps's body proportions and whether butterfly really is the most ridiculous stroke in swimming.

And after a rigorous scientific analysis, Dara turns out to be ideally suited for?netball. Much to his surprise.

Contributors Dr Polly McGuigan: University of Bath Dr Mitch Lomax: University of Portsmouth Professor Alun Williams: Manchester Metropolitan University Dr Josephine Perry: Sports psychologist

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Listener Vivienne has heard that tardigrades - aka moss piglets - have special powers of survival. Radiation? Drought? Extreme cold? NO PROBLEM. Does that mean they could survive an apocalypse? And could they even help us master space travel!?

Hannah and Dara learn how to find these little moss piggies in roof gutters and garden corners. And they're amazed by their capacity to dry out and hunker down for decades before springing back to life. But calamity strikes when it turns out that fine glass tubing - in the form of pipettes - is their natural predator. And worse is to come: our curious duo learn that there may be some tardigrades stuck on the moon, and one researcher has even fired them out of a gun. All in the name of science.

But they have survived at least 5 mass extinctions so far. So their chances of surviving the next one are pretty good. As long as pipettes aren't involved. Contributors Dr James Frederick Fleming: Natural History Museum of Norway and the University of Oslo Dr Nadja Møbjerg: University of Copenhagen Dr Thomas Boothby: University of Wyoming

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

If there?s one type of discharge you really want to avoid, it?s lightning, but what happens when it hits you?

We hear from lightning survivor Kerry Evans, and discover that the best place to shelter ? if you ever find yourself in a similarly charged storm ? is in a car, or low to the ground. And why this is never a good time to take a selfie.

Dr Dan Mitchard from Cardiff University?s excitingly-named Lightning Lab explains why there's no lightning at the poles, and the presenters lament that polar bears and penguins are missing out.

We all know about the gods of lightning, but the mysticism doesn't stop there. Above cloud level there are many other types of unusually-named phenomena, reaching to the edge of space, including sprites, trolls and even pixies.

And Professor Karen Aplin reveals that lightning has even been discovered on other planets, in a science story that could affect our plans to colonise Mars.

Contributors:

Dr Daniel Mitchard, Lightning Laboratory, Cardiff University Professor Karen Aplin, University of Bristol

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

11 year old Esther visualises days of the week in a kind of 3D structure. It?s something called ?synaesthesia? and she wants to know why it happens - and why other people don?t experience things the way she does.

Hannah Fry and Dara Ó Briain explore the vibrant and varied ways different people experience the world, from the man who tastes individual words - including all the stops of the tube - to the composer who sees music in shapes and colours.

And along the way, they figure out why Mozart is white wine while Beethoven is red.

Contributors:

Professor Julia Simner: Professor of Psychology,University of Sussex Professor Jamie Ward: Professor of Cognitive Neuroscience, University of Sussex James Wannerton, President of UK Synaesthesia Association CoriAnder: electronic music producer

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

It?s sometimes said that timing is everything and this week the pair investigate the mystery of rhythm, discovering why some of us might be better at staying in tempo.

From the daily cycle of dawn and dusk to sea tides and circadian clocks, rhythm governs many aspects of our lives, and cognitive psychologist Dr Maria Witek says it makes sense we also place great importance on its presence in music. She specialises in ?groove?, or the feeling of pleasure associated with moving to a beat ? and it?s not just something the dancers among us enjoy; groove has even been used to treat patients with Parkinson?s Disease.

Neuroscientist Professor Nina Kraus has studied drummers? brains and found their neurons fire with more precision. She explains that teaching kids rhythm can improve their language and social skills. But no need to take her word for it, because Skunk Anansie?s drummer Mark Richardson is in the studio to put Hannah to the test. Can she handle a high hat at the same time as a snare?

Contributors: Dr Maria Witek, University of Birmingham Professor Nina Kraus, Northwestern University Mark Richardson, drummer with Skunk Anansie

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

9 year old listener Koby sends Hannah and Dara on a mission to find the shiniest thing in the world. And so they enter a world of mirrors?

The journey takes them into the subatomic goings on of shiny metal surfaces, where electrons waggle and dance and send light waves back at *just* the right angle. Our curious duo play with an astonishingly reflective plastic film that can be found hidden in devices we all use. And they probe the mysterious power of refraction, harnessed to make the $2 million mirrors which reflect the lasers at the huge LIGO experiment.

And everyone ponders the surprisingly reflective properties of a pint in space.

Contributors:

Dr Felix Flicker: University of Bristol, author of The Magick of Matter Professor Stuart Reid: University of Strathclyde Quinn Sanford: optical engineer from 3M GariLynn Billingsley: Optical Sciences Group Leader at LIGO

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Would you eat food that fell on the floor? That?s the question Hannah and Dara are getting their teeth into this week as they put the so-called ?5 second rule? through its paces.

For some people it?s 3 seconds, and for others its 10 ? especially if it involves a dropped ice cream and a screaming child. But microbiologist Don Schaffner says there?s no safe amount of time to leave food on the floor if you?re planning to eat it. And while you might think buttered toast would pick up the biggest number of bugs, it may surprise you to hear that wet foods like watermelon are actually the worst when it comes to attracting harmful bacteria. If all this is putting you off your dinner, the bad news is that the rest of your kitchen is also a microbiological minefield. Research shows nearly 70% of us keep our fridges are the wrong temperature, which sparks a lively discussion about whether it?s ever safe to reheat rice.

For home hygiene guru Sally Bloomfield it?s all a question of being a bit more clever about the kind of germs we expose ourselves to and weighing up risks.

Contributors:

Dr Don Schaffner: Rutgers University Dr Ellen Evans: Cardiff Metropolitan University Professor Sally Bloomfield: International Scientific Forum on Home Hygiene

Producer: Marijke Peters Executive Producer: Alexandra Feachem A BBC Studios Audio Production

While chatting at the back of class, best mates Abi and Sofia got curious about bubbles. How do you make really giant ones? Could you even get one around the entire planet?

Hannah and Dara set out to investigate. They hear from a renowned 'bubbleologist', and learn how NASA helped him blow his way to a world record. They coax a physicist to reveal the secrets of his peer-reviewed bubble-juice formula, and investigate how bubbles work in space and in the ocean.

Our curious duo also discover an audacious project aiming to build a Brazil-sized raft of bubbles... in space!

Contributors:

Dr Helen Czerski, UCL Dr Justin Burton, Emory University Dr Awesome, Bubbleologist Professor Carlo Ratti, MIT

Producer: Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

Curious Cases is returning! Superstar mathematician and broadcaster Hannah Fry teams up with legendary comedian and fellow science nerd Dara Ó Briain for an all-new series of the show which takes your quirkiest questions and solves them with the power of science.

In this short preview ep, our dynamic duo tease some of the upcoming episodes in which they enlist the world?s top experts to tackle the most profound and puzzling questions to have ever trickled through your curious minds: Could you power a spaceship with a lemon? Can you actually die of boredom? Why do some people *taste* words? Why does Hannah have absolutely no sense of rhythm? And could we stop climate change with massive space bubbles!?

Producers: Marijke Peters and Ilan Goodman Executive Producer: Alexandra Feachem A BBC Studios Audio Production

There is a bizarre number in maths referred to simply as ?i?. It appears to break the rules of arithmetic - but turns out to be utterly essential for applications across engineering and physics. We?re talking about the square root of -1. WHICH MAKES NO SENSE.

Professor Fry waxes lyrical about the beauty and power of this so-called ?imaginary? number to a sceptical Dr Rutherford. Dr Michael Brooks tells the surprising story of the duelling Italian mathematicians who gave birth to this strange idea, and shares how Silicon Valley turned it into cold hard cash. It's all about oscillations, Professor Jeff O?Connell demonstrates. And finally, Dr Eleanor Knox reveals that imaginary numbers are indispensable for the most fundamental physics of all: quantum mechanics.

Imaginary, impossible?but essential!

Contributors: Professor Jeff O?Connell, Ohlone College California, Dr Michael Brooks, Author of 'The Maths That Made Us', and Dr Eleanor Knox, Philosopher of Physics at KCL and a Senior Visiting Fellow at the University of Pittsburgh.

Producer: Ilan Goodman

This episode will render you oblivious, conked out and blissfully unaware. It?s about anaesthetics: those potent potions that send you into a deep, deathly sleep. Listener Alicia wants to know how they work, so our sleuths call on the expertise of consultant anaesthetist Dr Fiona Donald. Fiona shares her experience from the clinical frontline, and explains what we do and don?t know about how these chemicals work their mind-numbing magic. We hear about ground-breaking research led by Professor Irene Tracey, which reveals how a pattern of slow brain waves can be used to determine the optimum dosage of these dangerous drugs.

And finally, Drs Rutherford and Fry wonder: what does all this tell us about normal consciousness? Professor Anil Seth shares how we can use brain tech to measure different levels of conscious awareness ? from sleepy to psychedelic.

Presenters: Hannah Fry and Adam Rutherford Producer: Ilan Goodman

?Can we bring back extinct species?? wonders listener Mikko Campbell. Well, Professor Fry is pretty excited by the prospect of woolly mammoths roaming the Siberian tundra once more. And everyone is impressed with the science that might make it happen. But Dr Rutherford comes out STRONGLY against the whole thing. Can our expert guests win him over?

Dr Helen Pilcher shares the tale of Celia the lonely mountain goat, and makes the case for cloning to help protect species at risk of extinction. Professor Beth Shapiro sets out how biotech company ?Colossal? plans to engineer Asian elephants? DNA to make a new group of mammoth-like creatures. And we hear how genetic technologies are being used in conservation efforts around the world.

BUT WHAT ABOUT T-REXES? Not gonna happen. Sorry.

Contributors: Dr Helen Pilcher, author of ?Bring Back the King: The New Science of De-Extinction?, Professor Beth Shapiro from the University of California Santa Cruz, Dr Ben Novak of Revive and Restore and Tullis Matson from Nature?s SAFE.

Presenters: Hannah Fry and Adam Rutherford

Producer: Ilan Goodman

The Great Pyramids of Giza are awesome feats of engineering and precision. So who built them - and how? Was it a mysteriously super-advanced civilization now oddly extinct? Was it even aliens?

Nah, course not! Rutherford and Fry investigate how these inspiring monuments were really constructed, and learn about the complex civilisation and efficient bureaucracy that made them possible.

Professor Sarah Parcak busts the myth that they were built by slaves. In fact, she reveals, it was gangs of well-paid blokes fuelled by the ancient Egyptian equivalent of burgers and beer. And Dr Chris Naunton explains how it was not some mysterious tech, but incredible organisation and teamwork which made it possible to transport massive stone blocks over long distances several thousand years before trucks arrived.

Dr Heba Abd El Gawad points out how racism led to bizarre assumptions in the history of archaeology, and how those assumptions linger in contemporary conspiracy theories which refuse to accept that Egyptians could have built the pyramids themselves!

Presenters: Hannah Fry and Adam Rutherford Contributors: Professor Sarah Parcak, University of Alabama, Dr Chris Naunton, Egyptologist and broadcaster, Dr Heba Abd El Gawad, University College London Producers: Ilan Goodman & Emily Bird

Magnets are inside loads of everyday electronic kit - speakers, motors, phones and more - but listener Lucas is mystified: what, he wonders, is a magnetic field?

Our sleuths set out to investigate the mysterious power of magnets, with the help of wizard / physicist Dr Felix Flicker - author of the The Magick of Matter - and materials scientist Dr Anna Ploszajski.

They cover the secrets of lodestones - naturally occurring magnetic rocks - and how to levitate crystals, frogs and maybe even people.

Matthew Swallow, the Chair of the UK Magnetics Society, explains why magnets make the best brakes for rollercoasters, and Dr Ploszajski explains how magnetically-induced eddy currents are used to sort through our recycling.

Finally, Dr Flicker persuades Adam and Hannah that to really understand magnetic fields you have to leave classical physics behind, and go quantum... So our sleuths take a leap into the strange subatomic realm.

Contributors: Dr Felix Flicker, Lecturer in Physics at Cardiff University and author of ?The Magick of Matter?, Dr Anna Ploszajski, materials scientist and author of ?Handmade?, Matthew Swallow, Chair of the UK Magnetics Society

Presented by Hannah Fry and Adam Rutherford Producer: Ilan Goodman

Close your eyes and think of a giraffe. Can you see it? I mean, *really* see it - in rich, vivid detail? If not - you aren?t alone! We?ve had scores of messages from listeners who report having a ?blind mind?s eye?. They don?t see mental images at all and they want to know why. Jude from Perth wants to know what makes her brain different, and Diane from Scotland wonders whether it affectes her ability to remember family holidays.

Our sleuths learn that this is a condition recently termed ?aphantasia?. They meet the chap who came up with the name, Professor Adam Zeman, a neurologist from the University of Exeter, and quiz him on the brain mechanisms behind this mystery. Professor Julia Simner - a psychologist who, herself, doesn?t see mental images - shares the surprising research into how aphants differ slightly from others in a range of cognitive skills. We also hear about the world class artists and animators who can?t visualise - but can create beautiful, imaginary worlds. Philosophy professor Fiona Macpherson from the University of Glasgow, deepens the mystery: perhaps this largely hidden phenomenon is behind some of the most profound disagreements in the history of psychology. Our mental experiences are all very different - maybe that?s why thinkers have come up with such different theories about how our minds work. Search for the ?VVIQ? or Vividness of Visual Imagery questionnaire to take the test yourself. Look for ?The Perception Census? to take part in this massive online study of perceptual variation. And look up the 'Aphtantasia Network' if you're curious to find out more.

Presenters: Hannah Fry and Adam Rutherford Contributors: Professor Adam Zeman, Professor Julia Simner, Professor Fiona Macpherson Producer: Ilan Goodman

What do you get if you smash two hydrogen nuclei together? Helium and lots of energy. That?s no joke ? it's nuclear fusion!

Nuclear fusion is the power source of the sun and the stars. Physicists and engineers here on earth are trying to build reactors than can harness fusion power to provide limitless clean energy. But it?s tricky...

Rutherford and Fry are joined by Dr Melanie Windridge, plasma physicist and CEO of Fusion Energy Insights, who explains why the fourth state of matter ? plasma ? helps get fusion going, and why a Russian doughnut was a key breakthrough on the path to fusion power.

Dr Sharon Ann Holgate, author of Nuclear Fusion: The Race to Build a Mini Sun on Earth, helps our sleuths distinguish the more familiar nuclear fission (famous for powerful bombs) from the cleaner and much less radioactive nuclear fusion.

And plasma physicist (another one!) Dr Arthur Turrell describes the astonishing amount of investment and innovation going on to try and get fusion power working at a commercial scale.

Contributors: Dr Melanie Windridge, Dr Sharon Ann Holgate, Dr Arthur Turrell

Producer: Ilan Goodman

Sneezes, wheezes, runny noses and red eyes - this episode is all about allergies. An allergic reaction is when your immune system reacts to something harmless ? like peanuts or pollen ? as if it was a parasitic invader. It?s a case of biological mistaken identity. Professor Judith Holloway from the University of Southampton guides our sleuths through the complex immune pathways that make allergies happen and tells the scary story of when she went into anaphylactic shock from a rogue chocolate bar. Professor Adam Fox, a paediatric allergist at Evelina Children?s Hospital, helps the Drs distinguish intolerances or sensitivities ? substantial swelling from a bee sting, for example - from genuine allergies. Hannah?s orange juice ?allergy? is exposed as a probable fraud! Hannah and Adam explore why allergies are on the increase, and Professor Rick Maizels from the University of Glasgow shares his surprising research using parasitic worms to develop anti-allergy drugs! Producer: Ilan Goodman Contributors: Professor Judith Holloway, Professor Adam Fox, Professor Rick Maizels

Hungry for pi? Chow down on this!

Pi is the ratio between a circle?s diameter and its circumference. Sounds dull ? but pi turns out to have astonishing properties and crop up in places you would never expect. For a start, it goes on forever and never repeats, meaning it probably contains your name, date of birth, and the complete works of Shakespeare written in its digits.

Maths comedian Matt Parker stuns Adam with his ?pie-endulum? experiment, in which a chicken and mushroom pie is dangled 2.45m to form a pendulum which takes *exactly* 3.14 seconds per swing.

Mathematician Dr Vicky Neale explains how we can be sure that the number pi continues forever and never repeats - despite the fact we can never write down all its digits to check! She also makes the case that aliens would probably measure angles using pi because it?s a fundamental constant of the universe.

NASA mission director Dr Marc Rayman drops in to explain how pi is used to navigate spacecraft around the solar system. And philosopher of physics Dr Eleanor Knox serves up some philoso-pi, revealing why some thinkers have found pi?s ubiquity so deeply mysterious.

Hannah grins with delight for most of show. It?s all maths!

Producer: Ilan Goodman

Contributors: Matt Parker, Dr Vicky Neale, Dr Marc Rayman, Dr Eleanor Knox

Why are some smells so nasty and others so pleasant? Rutherford and Fry inhale the science of scent in this stinker of an episode.

Our sleuths kick off with a guided tour of the airborne molecules and chemical receptors that power the sense of smell. Armed with a stack of pungent mini-flasks, Professor Matthew Cobb from the University of Manchester shows Hannah and Adam just how sensitive olfaction can be, and how our experience of some odours depends on our individual genetic make-up.

Dr Ann-Sophie Barwich from Indiana University reveals how most everyday smells are complex combinations of hundreds of odorants, and how the poo-scented molecule of indole turns up in some extremely surprising places.

With the help of a flavoured jellybean and some nose clips, Hannah experiences how smell is crucial to flavour, adding complexity and detail to the crude dimensions of taste.

Speaking of food, listener Brychan Davies is curious about garlic and asparagus: why do they make us whiff? Professor Barry Smith from the Centre for the Study of the Senses reveals it's down to sulphur-containing compounds, and tells the story of how a cunning scientist managed to figure out the puzzle of asparagus-scented urine.

Finally, another listener Lorena Busto Hurtado wants to know whether a person?s natural odour influences how much we like them. Barry Smith says yes - we may sniff each other out a bit like dogs - and cognitive neuroscientist Dr Rachel Herz points to evidence that bodily bouquet can even influence sexual attraction!

Producer: Ilan Goodman

Contributors: Professor Matthew Cobb, Professor Barry Smith, Dr Ann-Sophie Barwich, Dr Rachel Herz

How do winds start and why do they stop? asks Georgina from the Isle of Wight. What's more, listener Chris Elshaw is suprised we get strong winds at all: why doesn't air just move smoothly between areas of high and low pressure? Why do we get sudden gusts and violent storms?

To tackle this breezy mystery, our curious duo don their anoraks and get windy with some weather experts.

Dr Simon Clark, a science Youtuber and author of Firmament, convinces Adam that air flow is really about the physics of fluids, which can all be captured by some nifty maths. The idea of pressure turns out to be key, so Hannah makes her own barometer out of a jar, a balloon and some chopsticks, and explains why a bag of crisps will expand as you walk up a mountain.

Professor Liz Bentley, Chief Executive of the Royal Meteorological Scoiety, reveals how the dynamics of a simple sea breeze ? where air over land is heated more than air over water ? illustrates the basic forces driving wind of all kinds.

Then everyone gets involved to help Adam understand the tricky Coriolis effect and why the rotation of the Earth makes winds bend and storms spin. And Professor John Turner from the British Antarctic Survey explains why the distinctive features of the coldest continent make its coastline the windiest place on earth.

Producer: Ilan Goodman Contributors: Dr Simon Clark, Professor Liz Bentley, Professor John Turner

DO WE HAVE YOUR ATTENTION?

Good! But how does that work!?

Our intrepid science sleuths explore why some things immediately catch your eye - or ear - while others slip by totally unnoticed. Even, on occasion, basketball bouncing gorillas.

Professor Polly Dalton, a psychologist who leads The Attention Lab at Royal Holloway University, shares her surprising research into ?inattentional blindness? - when you get so absorbed in a task you can miss striking and unusual things going on right in front of you.

Dr Gemma Briggs from the Open University reveals how this can have dangerous everyday consequences: you are four times more likely to have a crash if you talk on the phone while driving - even handsfree.

Drs Rutherford and Fry also hear from stroke survivor Thomas Canning, who developed the tendency to ignore everything on the left side of space, despite his vision being totally intact. And Dr Tom Manly, from the University of Cambridge?s Cognition and Brain Sciences Unit, helps our sleuths unpack the neuroscience of this fascinating condition.

Producer: Ilan Goodman Contributors: Professor Polly Dalton, Dr Gemma Briggs, Dr Tom Manly