Dr Seth Berkley is an epidemiologist and global health leader whose career has been shaped by one central problem: vaccines save lives, but only if people can actually get them.

His 40-year career has spanned the global, from helping to build Uganda’s first HIV surveillance system and founding the International AIDS Vaccine Initiative; to leading Gavi, the Vaccine Alliance for more than a decade – overseeing the immunisation of hundreds of millions of children worldwide. And when COVID-19 struck, Seth co-founded COVAX, the global initiative designed to stop wealthy nations monopolising vaccines.

In conversation with Professor Jim Al-Khalili, Seth discusses the highs and lows of his globe-trotting career - from saving millions of young lives through vaccine distribution, to setting his own shattered leg after a climbing accident in Namibia - and addresses the huge challenge of tackling vaccine scepticism.

Presented by Jim Al-Khalili. Produced by Lucy Taylor. A BBC Studios production.

Hiranya Peiris is playing a starring role in a movie that promises to tell perhaps the greatest story of all time. However, it’s a movie with a difference – there’s no director and no script. The Legacy Survey of Space and Time is one of the most ambitious projects in the world of astronomy, with a mission to create a decade-long time-lapse movie of the visible universe, to answer fundamental questions about its origin, evolution and, ultimately, its fate.

Hiranya is Professor of Astrophysics 1909, the prestigious Chair at the Institute of Astronomy at Cambridge University. Over her career she’s been one of the pioneers of a revolution in astronomy, bridging fundamental physics with the observational data coming back from space, to establish the first evidence-based standard model for the origin, evolution and fate of the universe. The endeavour has transformed the field from the ‘wild west’ of physics to the modern era of precision cosmology.

Ironically, it was another movie, of sorts, Carl Sagan’s documentary series ‘Cosmos’, that first sparked Hiranya’s interest in the universe as a young girl. Always keen to inspire women to follow in her footsteps and choose careers in science, if this interview were a live show she’d have reserved the front row for schoolgirls.

Presented by Jim Al-Khalili Produced by Beth Eastwood A BBC Studios production

As a child growing up on the shores of Lake Victoria in western Kenya, Washington Yotto Ochieng once watched a plane cross the night sky and told his mother he wished he could travel on it. But he remembers her encouraging him to dream bigger...

Today, Washington is a Professor of Engineering at Imperial College London, and President of the Royal Institute of Navigation. Over a career bridging industry and academia, he has helped shape the movement of urban transport; how satellites guide us and locate us; and how governments manage the technologies underpinning so much of modern life.

Professor Jim Al-Khalili speaks to Washington about his inspirational upbringing, how reliant we've become on technologies such as GPS, and his work encouraging the next generation of engineers in both the UK and Africa.

Presented by Jim Al-Khalili Produced by Lucy Taylor

A BBC Studios production

Working on a remote tropical island in the Atlantic might sound like some sort of romantic idyll - but trying to conduct scientific research on a windy, isolated volanic outcrop is no picnic, as Lucy Carpenter can attest!

Lucy is an atmopsheric chemist and a Professor at the University of York, whose work has helped to transform understanding of how oceans shape the air above them. She was one of the founding scientists behind the Cape Verde Atmospheric Observatory, established on São Vicente in 2006 and now a key global monitoring site. Measurements made there helped overturn a long-standing assumption: ozone loss is not solely a human-made problem. Lucy and her colleagues showed that gases released by natural marine processes can trigger chemical reactions that destroy ozone - demonstrating that the sea is not simply a passive backdrop to climate change but an active participant; affecting aerosols, clouds and ultimately the climate itself.

More recently Lucy's expertise has taken her into the policy arena, co-chairing the scientific assessment panel for the Montreal Protocol: the international agreement designed to protect the ozone layer.

In conversation with Professor Jim Al-Khalili, Lucy dicusses her journey from sampling ocean air to turning the tide of global environmental policy - and explains why her passion for duathlons could arguably be seen as an easier pastime than scientific research.

Presented by Jim Al-Khalili Produced by Lucy Taylor A BBC Studios production

As recently as a few years ago, the idea of a self-administered injection that would deliver proven weight-loss results might have sounded fantastical. Today, these medications are a reality and a global phenomenon; hailed in many quarters as “miracle drugs" for their success in treating obesity and diabetes.

They do this by replicating a gut hormone called GLP‑1, which tells the brain you’ve eaten enough and nudges the pancreas to release insulin; and this hormone was discovered and decoded thanks to years of work by today's guest.

Jens Juul Holst is a Professor of Medical Physiology and Biomedical Sciences at the University of Copenhagen. His efforts laid the groundwork for today’s weight loss jabs, earning him a slew of high-profile accolades and awards. Now it seems they might not only have positive impacts on obesity and diabetes, but also other health issues...

But alongside the big success comes some big questions: including concerns over side effects, weight regain post-treatment, the black market in such drugs, and their cost and accessibility.

In a frank conversation with Professor Jim Al-Khalili, Jens address these issues and shares his hopes for the future of GLP-1-focused research.

Presented by Jim Al-Khalili Produced by Lucy Taylor A BBC Studios production

It's a rare thing to encounter a medical specialist who has experience of his field from the expert and the patient perspective - but not unheard of...

Jim Ashworth-Beaumont is an orthotist and prosthetist who spent years helping people adapt to life with artificial limbs and musculoskeletal supports, before a near-fatal accident left him relying on both.

This twist of fate might have derailed many - but Jim drew on reserves of resilience and determination forged long before his accident; initially in the army, then by returning to education to earn the qualifications he missed out on as a youngster. He put himself through night school before earning a place to study Prosthetics and Orthotics at the University of Strathclyde. Later, while working at London’s Royal National Orthopaedic Hospital, Jim completed a Master’s in Neurorehabilitation, and a PhD in Health Studies – driven by a fascination with how the human body adapts under pressure.

But in 2020, while training for a triathlon, Jim was involved in a catastrophic cycling accident that nearly killed him - and cost him an arm. He tells Jim Al-Khalili how the incident gave him a whole new insight into his patients’ experience and made him more determined than ever to achieve his goals.

Presented by Jim Al-Khalili Produced by Lucy Taylor

A BBC Studios production for Radio 4

Ever heard of the unsuccessful Dutch painter who decided to humiliate his critics by forging Vermeers, which the artworld subsequently dubbed 'masterpieces'? Or the businessman who bought a Marc Chagall painting that he displayed with pride for years, before a television investigation revealed to his horror that it was a fake?

Today we're exploring the scientific techniques used to reveal forged artworks - and bring down scammers still trying to make millions from fake masterpieces.

Jehane Ragai is an Emeritus Professor of Chemistry at the American University in Cairo, with a passion for science matched by her love of arts and culture. Early in her career Jehane helped analyse the Great Sphinx of Giza and later became fascinated by the world of art forgery, leading to her acclaimed book, ‘The Scientist and the Forger’.

Her life has not been without its difficulties, but - perhaps unsurprisingly, as the daughter of renowned Egyptian feminist Doria Shafik - she’s not one to shy away from a challenge. And as she tells Professor Jim Al-Khalili, Jehane feels priveleged to have been able to integrate her twin passions into a career; advice she now passes on to her students.

Presented by Jim Al-Khalili Produced by Lucy Taylor

A BBC Studios production for Radio 4

Tony Juniper is an environmentalist who has worn many hats, over the course of his career.

After developing a passion for birds in childhood, his first job saw him working to save endangered parrots - including a successful effort to bring back the Spix's macaw from the edge of extinction. Tony went on to hold leading campaigning roles with some of the world's best known environmental organisations, from Friends of The Earth to the World Wildlife Fund. He also acted as an advisor to King Charles's International Sustainability Unit and co-authored three books with the monarch.

Today, Tony has swapped lobbying and campaigning for advising the government, as head of the advisory body Natural England: not without its challenges, but he says they are still outweighed by the positives.

Talking to Professor Jim Al-Khalili about his enduring love for nature and hopes for the future, Tony explains his optimism that we can and will recognise the urgent need to protect and restore our planet; and why ultimately, that means saving ourselves.

Presented by Jim Al-Khalili Produced by Lucy Taylor for BBC Studios

The COP30 climate summit is taking place in the Brazilian city of Belém, a gateway to the Amazon rainforest, which continues to face widespread deforestation. We all know that our climate is changing and that we are largely responsible for this, but we can’t tackle the problem unless we understand what’s going on.

One scientist who’s done more than most to rectify this is Professor Pierre Friedlingstein. He’s a prominent climate scientist and Chair in Mathematical Modelling of the Climate System at Exeter University. His models have transformed our understanding of climate change, revealing a complex dynamical system with carbon at its centre, cycling between the atmosphere, oceans and land, to directly influence the level of carbon dioxide in the atmosphere.

Pierre is actively involved in assessing the state of our climate through the Intergovernmental Panel on Climate Change and, as director of the Global Carbon Budget, estimates the remaining amount of carbon dioxide that can be emitted before we breach our global climate targets. It’s the ultimate test of effective climate action and the latest annual update will be released at COP.

Pierre explains how we can all play our part to reduce carbon emissions, and he practises what he preaches - he won’t be flying to COP this year so as to minimise his own carbon footprint.

Presented by Jim Al-Khalili Produced by Beth Eastwood Executive Producer: Alexandra Feachem A BBC Studios Production

Imagine if you were listening to an opera or a Taylor Swift concert, and as the lights in the auditorium dimmed, the music was accompanied by a rainbow of colours only you could see. Perhaps while listening to your friends talking, you simultaneously experience a smorgasbord of tastes, with different words evoking different flavours, maybe a delicious ice cream, or something as disgusting as ear wax... This merging of the senses is known as synaesthesia, and it’s the rich research world of neuropsychologist Professor Julia Simner. Julia runs the Multisense lab at the University of Sussex and has pioneered research into understanding how special brains process our sensory world in special ways. In the studio she tests Jim to see if he might be a synaesthete or have aphantasia, which is the inability to view images in the mind’s eye. The results are surprising. Julia’s discovered links to autism, and to different personality types, as well as a number of previously unknown sensory differences. She describes her career and her life as a series of swerves, or sliding door moments, that have led her to study the subject and the people she’s passionate about. She says that the more she looks for these unusual traits in us the more she finds.

Presenter Jim Al-Khalili Producer Geraldine Fitzgerald Executive Producer Alexandra Feachem

Caroline Smith is passionate about space rocks, whether they’re samples collected from the surface of asteroids and the Moon and hopefully Mars one day soon, or meteorites, those alien rock fragments that have survived their fiery descents through our atmosphere to land here on Earth.

She is Head of Collections and Principal Curator of Meteorites at the Natural History Museum, home to one of the finest meteorite collections in the world. Her interest in rocks began while wandering the foothills of the Rocky Mountains, as a child, picking up the ones that caught her eye and bashing them with a hammer, hoping to find treasure inside, whether it’s gold, diamonds or dinosaur fossils.

Her work today, studying rocks that have landed here on Earth or those still out there in space, is no less ambitious. She analyses their chemical composition looking for tantalising clues that might reveal how our Solar System formed, and potentially the presence of the chemical building blocks necessary for life itself.

Presented by Jim Al-Khalili Produced by Beth Eastwood Executive Producer: Alexandra Feachem BBC Studios Production