Imagine a nanoparticle, less that a thousandth of the width of a human hair, that is so precise that it can carry a medicine to just where it’s needed in the body, improving the drug’s impact and reducing side effects.

Ijeoma Uchegbu, Professor of Pharmaceutical Nanoscience at University College London, has spent her career with this goal in mind. She creates nanoparticles to carry medicines to regions of the body that are notoriously hard to reach, such as the back of the eye and the brain. With clinical trials in the pipeline, she hopes to treat blindness with eyedrops, transform pain relief and tackle the opioid crisis.

Ijeoma took an unconventional route into science. Growing up in the UK and in Nigeria, she tells Professor Jim Al-Khalili her remarkable life story, from being fostered by a white family in rural Kent, while her Nigerian parents finished their studies, to struggling to pay the bills through her PhD as a single mum with young children.

So passionate is Ijeoma to spread her love of science, she’s even turned to stand-up comedy to help get her message across!

Darren Croft studies one of the ocean’s most charismatic and spectacular animals – the killer whale. Orca are probably best known for their predatory behaviour: ganging up to catch hapless seals or attack other whales. But for the last fifteen years, Darren Croft’s focus has been on a gentler aspect of killer whale existence: their family and reproductive lives .

Bill Gates is one of the world's best-known billionaires - but after years at the corporate coalface building a software empire and a vast fortune, his priority now is giving that wealth away. And his ethos for doing it has been shaped by science.

Famed for co-founding Microsoft, in recent decades Bill’s attention has turned to philanthropy via The Gates Foundation: one of the largest charities in the world. Since its inception in 2000, the organisation has helped tackle issues around health, education, inequality and climate change in some of the world’s poorest countries, with an undeniable impact, from contributing to the eradication of wild poliovirus in Africa, to helping halve global child mortality rates within 25 years.

But, as Jim al-Khalili discovers, for a man with lofty ambitions and an even loftier bank balance Bill has surprisingly humble tastes.

A small, informal survey leads to shocking revelations about the US justice system, with its truths only uncovered decades later. Meanwhile, an ambitious portfolio manager discovers a perfect graph outlining eye-watering profits. But something does not seem right. Could the graph be accurate, or is it hiding a far more sinister truth? This story delves into the power of data, the hidden forces behind it, and the unexpected revelations that can change everything

At a conference in Mexico, one scientist’s outburst sparks a global quest to find a ‘golden spike’ - the boundary marking the shift into a new geological period dominated by humans, not volcanoes or asteroids. From plastics and concrete to nuclear fallout, the data they uncover reveals a planet profoundly altered. But can they convince their colleagues and the world of the extent of this transformation? Meanwhile, in a small Italian city nestled in the Apennine mountains, a series of low-level tremors raise the question: Is this just a passing phase, or a warning of something much more devastating?

A PhD student with a passion for whales stumbles upon a strange, eerie sound deep beneath the ocean waves, something that will soon rock her world. Meanwhile, a fisherman is stranded in the ocean late at night, completely alone. With time running out, can he be rescued before it is too late? From mysterious discoveries to life-or-death struggles, this story delves into the power of the ocean and the determination to survive.

Amid the desperation of war-starved Netherlands, a doctor defies conventional wisdom to save gravely ill children, uncovering a treatment that sparks both hope and controversy. Years later, in 1967, a young female researcher detects a strange, pulsing signal. Could it be mundane interference or evidence of alien life? From lifesaving breakthroughs to cosmic discoveries, this story celebrates the determination of pioneers who challenge convention and pursue truth against the odds.

A mathematician searching for love discovers that relationships aren’t always as simple as equations—are his calculations the issue, or is there something deeper at play? Meanwhile, at an engineering conference, a young researcher’s seemingly minor mistake uncovers a scandal of epic proportions. Can numbers find love or unveil problems? From personal dilemmas to professional revelations, this episode dives into the unexpected ways numbers can change lives.

In 2016, Niall McCann was left with a bruised spinal cord when he crashed his speed glider into the side of a mountain at 50mph.

He shares his journey to recovery and some unexpected life lessons he has had to navigate, from soiling himself in inconvenient places and not being able to control his flatulence, to having to re-learn how to have sex again.

We also hear from a Mountain Rescue medic on what looked like an “unsurvivable” situation and Niall’s surgeon on fixing his “exploded” spine.

Perhaps you couldn't drift off, or maybe you woke in the middle of the night and then couldn't nod off again.