What is it like to be young and find out you have got cancer? What you will find out in this film may surprise you. This film, narrated by actor and comedian Jack Whitehall, tells 11 inspirational stories, revealing how a range of young people have dealt with their cancer diagnosis and the treatment process. We hear, primarily in their own words, about their fears, their hopes and their experiences - affirming the view that 'the best therapist for a teenager with cancer... is another teenager with cancer.'

Time travel is not forbidden by the laws of nature, but to build a time machine, we would need to understand more about those laws and how to subvert them than we do now. And every day, science does learn more. In this film Horizon meets the scientists working on the cutting edge of discovery - men and women who may discover how to build wormholes, manipulate entangled photons or build fully functioning time crystals. In short, these scientists may enable an engineer of the future to do what we have so far been only able to imagine - to build a machine that allows us travel back and forward in time at the touch of a button. It could be you! Science fiction? Watch this space.

One in every 1,000 pregnancies in Britain has a spine or brain defect like spina bifida. 30 years ago, actress Ruth Madeley was one of them. Despite having spina bifida herself, it is a condition she doesn't fully understand. In this programme, Ruth sets out to discover why she has it, whether it could have been prevented and what it means for her future. Ruth meets the lord campaigning for a change in the law that he says could prevent thousands of birth defects. And she discovers that a pioneering surgery could offer a different future for babies diagnosed with spina bifida, by operating on them before they are even born. She discovers how this surgery was invented, meets the families whose lives it has changed and follows the team of British surgeons preparing to perform this extraordinary foetal surgery in the UK for the very first time. But Ruth also examines attitudes in Britain today and asks whether we should change the way we see disability.

'To send a spacecraft there is a little bit insane,' says Scott Bolton when talking about Jupiter, the largest planet in the solar system. But that is exactly what he has done, because Scott is head of Juno, the Nasa mission designed to peer through Jupiter's swirling clouds and reveal the wonders within. But this is no ordinary world. This documentary, narrated by Toby Jones, journeys with the scientists into the heart of a giant. Professor Kaitlin Kratter shows us how extreme Jupiter is. She has come to a quarry to measure out each planet's mass with rocks, starting with the smallest. Mercury is a single kilogram, and the Earth is 17. But Jupiter is on another scale entirely. It is seven tonnes - that is two and a half times the mass of all the other planets combined. On Kaitlin's scale it is not a pile of rocks, it is the truck delivering them. With extreme size comes extreme radiation. Juno is in the most extreme environment Nasa has visited. By projecting a 70-foot-wide, life-size Juno on a Houston rooftop, Scott shows us how its fragile electronics are encased in 200kg of titanium. As Scott puts it, 'we had to build an armoured tank to go there.' The team's efforts have been worthwhile. Professor Andrew Ingersoll, Juno's space weatherman, reveals they have seen lightning inside Jupiter, perhaps a thousand times more powerful than Earth's lightning. This might be evidence for huge quantities of water inside Jupiter. Prof Ingersoll also tells us that the Great Red Spot, a vast hurricane-like storm that could swallow the Earth whole, goes down as far as they can see - 'it could go down 1,000s of kilometres'. Deeper into the planet and things get stranger still. At the National Ignition facility in northern California, Dr Marius Millot is using powerful lasers normally used for nuclear fusion for an astonishing experiment. He uses '500 times the power that is used for the entire United States at a given moment' to crush hydrogen to the pressures inside Jupiter. Under these extreme conditions, hydrogen becomes a liquid metal. Juno is finding out how much liquid metallic hydrogen is inside Jupiter, and scientists hope to better understand how this flowing metal produces the most powerful aurora in the Solar System. But what is at Jupiter's heart? In Nice, Prof Tristan Guillot explains how Juno uses gravity to map the planet's centre. This can take scientists back to the earliest days of the solar system, because Jupiter is the oldest planet and it should contain clues to its own creation. By chalking out an outline of the Jupiter, Tristan reveals there is a huge rocky core - perhaps ten times the mass of Earth. It is now thought Jupiter started as a small rocky world. But there is a surprise, because Juno's findings suggest this core might be 'fuzzy'. Tristan thinks the planet was bombarded with something akin to shooting stars. As he puts it, 'Jupiter is quite unlike we thought'.

Suicide is the biggest killer of men under 50 in the UK - causing more deaths in this group than car accidents, and even more than cancer. This means that the most likely thing to kill Dr Xand Van Tulleken is himself. And he wants to know why. In this sensitive film, Xand finds out what we know about why people develop suicidal thoughts, and whether there is anything that we can do about it.

Deception is an integral part of human nature and it is estimated we all lie up to nine times a day. But what if we created a world in which we couldn't lie? In a radical experiment, pioneering scientists from across Europe have come together to make this happen. Brand new technology is allowing them to rig three British people to make it impossible for them to lie undetected. Then they will be challenged to live for a whole week without telling a single lie. It is a bold social experiment to discover the role of deception in our lives - to investigate the impact lying has on our mental state and the consequences of it for our relationships, and to ask whether the world would be a better or worse place if we couldn't lie.

Dr. Michael Mosley cures real pain with fake pills in Britain's largest ever placebo trial.

We all have a biological clock ticking away inside us that governs our daily rhythms. This affects our health as much as our diet and whether we exercise. So what can we do to manage this internal clock better? To find out, evolutionary biologist Ella Al-Shamahi locks former commando Aldo Kane in an abandoned nuclear bunker with no way of telling the time - for ten days. Monitored around the clock by a team of scientists, he carries out a barrage of tests to uncover exactly what makes our body clock tick. Above ground, Ella meets two time-starved couples to test the latest thinking on how we can manage our body clocks better. In trying to improve their sleep, and their lives, she uncovers practical advice that we can all take on board. Studies on shift workers show that regularly disrupting our sleep makes us more at risk of diabetes, heart disease and even cancer. So getting to grips with our biological clock couldn't be more important.

Can we predict avalanches? How can we save more lives? A team of scientists led by Prof Danielle George create a massive avalanche to find out.

Nearly half of us take a vitamin or mineral supplement every day, but what are these pills sold on every high street actually doing? Digging deeper than the eye-catching words on the packaging, Dr Giles Yeo investigates who really needs a supplement by putting our diets to the test.

Could a machine replace your doctor? Dr Hannah Fry explores the incredible ways AI is revolutionising healthcare - and what this means for all of us. This film chronicles the inside story of the AI health revolution, as one company, Babylon Health, prepare for a man vs machine showdown. Can Babylon succeed in their quest to prove their AI can outperform human doctors at safe triage and accurate diagnosis? Artificial intelligence is starting to transform healthcare beyond recognition - and tech companies large and small see almost limitless commercial opportunity. The ultimate vision is for accessible, affordable, better healthcare for almost everyone with a phone. In Britain this is already radically changing how some of us see our GPs. And in a world with a chronic shortage of doctors, but where even the very poor own mobile phones, it could be truly revolutionary. To witness this revolution from the inside, this film has privileged, behind-the-scenes access to ambitious British tech start-up Babylon Health, whose CEO Dr Ali Parsa declares with complete conviction 'we're going to do with healthcare what Google did with information.' Babylon launched its GP at Hand app in London in late 2017 and has already persuaded 30,000 Londoners to quit their old GPs to register instead for this NHS 'digital first' service, where patients discuss symptoms with an AI chatbot and see a doctor in minutes 24/7 via their phone. But GP at Hand's arrival has proved controversial - with many traditional GPs worried about the disruptive consequences for them and their patients, and others seeking to thwart its expansion nationwide. As this film reveals, there is a fundamental culture clash at play - between the 'move fast and break things' world of tech, and the cautious, diligent, often slow-moving world of medical science. So how will both camps respond when Babylon's AI attempts to pass the diagnostic sections of the Royal College of GPs exam? Amazingly, the NHS is today the largest purchaser of fax machines in the world - and the British government are eagerly embracing AI as the remedy for our public health system's antiquated inefficiencies. British health secretary Matt Hancock is an unabashed evangelist for tech - boasting Babylon's GP at Hand as his GP. Yet some scientists are increasingly alarmed, questioning the current hype and asking where is the proof that AI health apps, now in widespread use, are effective and safe. How should they be evaluated and regulated? And what needs to happen before we all trust our health to AI? As well as following a tumultuous year inside Babylon, both in the UK and Rwanda, the film also explores how another British AI Health start-up, Kheiron Medical, has successfully used deep learning to train its AI to detect breast cancer and now outperforms human radiologists at spotting the tell-tale signs of cancer in mammograms.

In recent years a groundbreaking new study has been released into the effects of the contraceptive pill. Research from Denmark claimed women on the pill and other forms of hormonal contraception were 70% more likely to be diagnosed with depression than those who were not. And another study has found hormonal contraception was linked to a seemingly dramatic risk of breast cancer. Negative headlines are nothing new for the contraceptive pill - first introduced in 1961, it has had a chequered history with early versions linked to cancer risk and life-threatening blood clots. Yet hormonal contraception remains Britain's most popular form of birth control, and today over three million women take regular doses of synthetic hormones. So should they be worried about its safety? GP Dr Zoe Williams gets behind the headlines in this Horizon investigation. A specially commissioned, nationwide survey reveals the areas of most concern to British women - from mental health to the risk of cancer and drop in libido. With the help of world leading scientists, Zoe finds out if these concerns are justified and by delving deep into the science around the pills side effects Horizon uncovers some striking revelations - from protecting women against cancer to increasing their risk of suicide.