There can't be many people in the world who've saved lives in hospital emergency rooms and also helped care for the wellbeing of astronauts in space – but Kevin Fong’s career has followed a singular path: from astrophysics and trauma medicine, to working with NASA, to becoming an Air Ambulance doctor.

Kevin is a consultant anaesthetist and professor of public engagement and innovation at University College London. He’s worked on the front line in hospitals, dealing with major incidents and helping shape policy; but he's also stayed true to his childhood passion for space, working on multiple projects with NASA and even going through the astronaut application process himself. As if that wasn’t enough, he’s also become a well-known figure in science broadcasting through his various radio and TV shows.

Speaking to Professor Jim Al-Khalili, Kevin admits it hasn't always been an easy path – but his passion for both space and medicine have got him through. And today, he's channelling his energies into ensuring we protect the NHS's most precious commodity: its staff.

Presented by Jim Al-Khalili

This programme was a BBC Studios Audio prouction for Radio 4.

Chemical reactions are the backbone of modern society: the energy we use, the medicines we take, our housing materials, even the foods we eat, are created by reacting different substances together. If we zoom in, it’s the atoms within these substances that rearrange themselves to give rise to new substances with the properties we need.

However, chemical reactions are far from perfect. They're often inefficient and their waste products can be harmful to the environment. Getting to grips with what goes on at the scale of individual atoms has long been a sticking point.

Dame Pratibha Gai has spent much of her career pioneering novel microscopes to bring this seemingly inaccessible atomic world into sharp focus. Now Emeritus Professor of Chemistry at York University, her microscope, known as the environmental transmission electron microscope, is housed in labs around the world. It allows scientists, like herself, to observe chemical reactions in real-time, in exquisite atomic detail, and tinker with them to create products that are not only better for all of us, but also the environment.

Presented by Jim Al-Khalili

Have you ever considered the lighter side of dark matter?

Astrophysicist Catherine Heymans is a Professor at the University of Edinburgh and the current Astronomer Royal for Scotland. She’s spent her career studying dark matter and dark energy: the mysterious ingredients that make up an estimated 95% of our cosmos, but which we still know surprisingly little about. Using increasingly powerful telescopes, both on earth and in space, Catherine has spent years building detailed maps of dark matter - even to the extent of capturing rare images of this mysterious cosmic component.

On top of her research achievements, she's committed to making science accessible to all; not least by taking an astronomy-themed comedy show to the Edinburgh Festival and beyond.

In conversation with Professor Jim Al-Khalili, Catherine talks about her passion for sharing the joys of astrophysics - and reveals how health challenges over the last few years have forced her to readdress her career, her ambitions and even her sense of self...

Presented by Jim Al-Khalili

As a young man, traveling in Africa, Tim Coulson - now Professor of Zoology at the University of Oxford - became seriously ill with malaria and was told a second bout would probably kill him. Aged only 20, this brush with his own mortality led him to promise himself he would write a complete guide to science: life, the universe and everything. His aim was to understand the existence of all living things - no mean feat!

Over the course of a colourful career, Tim's work has taken him all over the world: including researching wolves in Yellowstone National Park, little fish called guppies in the rivers of Trinidad and silvereye birds on Heron Island on the Great Barrier Reef. Using complicated mathematical models he builds up a picture of ecosystems seeking to explain how predators impact both evolution and ecosystems. And finally, more than thirty years after he vowed to write the book that would explain everything we know about science, he's done just that.

In conversation with Professor Jim Al-Khalili, Tim talks about his journey from youthful ambition to science demystifier.

Presented by Jim Al-Khalili

Claudia de Rham has rather an unusual relationship with gravity.

While she has spent her career exploring its fundamental nature, much of her free time has involved trying to defy it - from scuba diving in the Indian Ocean to piloting small aircraft over the Canadian waterfalls. Her ultimate ambition was to escape gravity’s clutches altogether and become an astronaut, a dream that was snatched away by an unlikely twist of fate.

However, Claudia has no regrets - and says defying gravity for much of her life has helped her to truly understand it.

As Professor of theoretical physics at Imperial College London, she now grapples with deep mathematics, where the fields of particle physics, gravity and cosmology intersect, on a quest to understand how the universe really works. She is a pioneer of the theory of massive gravity, a theory which could take us beyond even Einstein’s theory of relativity and shed light on why the universe is expanding at an ever-increasing rate.

Presented by Jim Al-Khalili

When you think of Artificial Intelligence, does it inspire confidence, or concern?

Although it's now generally accepted that this technology will play a major role in our future, a lot of conversations around AI and machine learning come back to the argument over us losing control and robots taking over.

Happily, Neil Lawrence has a more optimistic view of the power of AI, and how we might navigate the potential pitfalls. Neil is the DeepMind Professor of Machine Learning at the University of Cambridge, and over the course of his career has been involved in deploying AI and machine learning in both academic and commercial scenarios, with a stint at Amazon as well as working across fields as varied as movie animation, Formula 1 strategy, and medical research.

Speaking with Professor Jim Al-Khalili, Neil says ultimately his efforts are all about making a difference to our everyday lives - and that we need to learn how to embrace AI, albeit with a healthy dollop of scepticism; not least when it comes to how our data is used, and the power of 'the digital oligarchy'...

Presented by JIm Al-Khalili

A frozen, white world at the far-reaches of the globe, where you're surrounded by snow and silence, might sound rather appealing. Factor in temperatures that drop to -57°C and a few of us might be put off - but for glaciologist Liz Morris, that's very much her happy place.

Liz is an Emeritus Associate at the University of Cambridge’s Scott Polar Research Institute, and was among the first British women scientists to work on the planet’s coldest continent, Antarctica. Over the course of her career, Liz has gathered vital data on polar ice sheets and how they’re affected by climate change. She's also made numerous research trips across the Greenland Ice Shelf, and has a glacier named after her in Antarctica.

In conversation with Professor Jim Al-Khalili, Liz discusses her fascination with glaciers and ice - and explains her unwavering determination to break into what was once a heavily male-dominated field.

Presented by Jim Al-Khalili

Welcome to a world where medicine meets politics: a space that brings together scientific research, government wrangling, public push-back and healthcare conspiracies…

Dr Anthony Fauci was the Director of America’s National Institute of Allergy and Infectious Diseases for nearly four decades, during which time he not only helped study, treat and prevent viruses such as HIV/AIDS and Covid-19; he also advised seven US Presidents, from Ronald Regan through to Joe Biden.

Along the way, Tony Fauci's picked up a public profile and taken a fair amount of flack; not least because of his complicated relationship with President Donald Trump. But he's also made great strides in medical research and policy, from working with activists who initially challenged him on the government response to HIV/AIDS - to spearheading the USA's PEPFAR project to share vital medication with developing nations.

In a candid conversation with Professor Jim Al-Khalili, Tony discusses his childhood in Brooklyn, the dark early days of the HIV/AIDS epidemic, lessons from the Covid-19, his hopes and fears for the future of American health policy – and his reaction to that pre-emptive pardon from President Biden.

Presented by Jim Al-Khalili

Have you ever pondered the fact that the universe is expanding? And not only that, it's expanding at an increasing speed - meaning everything around us is getting further and further away?

If that isolating thought makes you feel slightly panicked, don't worry: this programme also contains wine!

Brian Schmidt is a Distinguished Professor of Astrophysics at the Australian National University, known for his work on supernovae: massive explosions that take place when stars come to the ends of their lives. They are among the most energetic events in the universe and incredibly difficult to find; but that’s what his High-Z Supernova Search Team did, identifying enough of these rare and distant explosions to measure just how fast they were moving away from us.

This led them to the realisation that, contrary to long-held belief in cosmology, the expansion of the universe was speeding up; a discovery which earned Brian a share of the 2011 Nobel Prize for Physics. As if that wasn't enough, he's gone on to discover one of the earliest stars in the universe; run a university; and become a winemaker, at his very own vineyard just outside Canberra.

In a conversation spanning the genius phraseology of writer Douglas Adams, the importance of pisco sours, and the similarities between astronomy and viticulture, Brian tells Professor Jim Al-Khalili how his supernovae breakthrough paved the way for a revolution in astronomy - and where the field needs to go next...

Presented by Jim Al-Khalili

How much information can you extract from a burnt fragment of human bone?

Quite a lot, it turns out - not only about the individual, but also their broader lives and communities; and these are the stories unearthed by Jacqueline McKinley, a Principal Osteoarchaeologist with Wessex Archaeology.

During her career, Jackie has analysed thousands of ancient burial sites across the British Isles, bringing to life the old traditions around death via often cremated human remains. She's also assisted criminal investigators with forensic analysis, and contributed to some of the UK's best-loved archaeological TV shows.

In conversation with Professor Jim Al-Khalili, Jackie talks about the stories we can derive from skeletal remains, how western attitudes to death have gone through a major recent shift, and why she's kept some of her late father's bones.

Presented by Jim Al-Khalili