Around the world, a new generation of astronomers are hunting for the most mysterious objects in the universe. Young stars, black holes, even other forms of life. They have created a dazzling new set of super-telescopes that promise to rewrite the story of the heavens. This film follows the men and women who are pushing the limits of science and engineering in some of the most extreme environments on earth. But most striking of all, no-one really knows what they will find out there.

Horizon explores the secrets of what makes a long, healthy and happy life. It turns out that a time you can't remember - the nine months you spend in the womb - could have more lasting effects on you today than your lifestyle or genes. It is one of the most powerful and provocative new ideas in human science, and it was pioneered by a British scientist, Professor David Barker. His theory has inspired a field of study that is revealing how our time in the womb could affect your health, personality, and even the lives of your children.

For centuries we have dreamt of reaching the centre of the Earth. Now scientists are uncovering a bizarre and alien world that lies 4,000 miles beneath our feet, unlike anything we know on the surface. It is a planet buried within the planet we know, where storms rage within a sea of white-hot metal and a giant forest of crystals make up a metal core the size of the Moon. Horizon follows scientists who are conducting experiments to recreate this core within their own laboratories, with surprising results.

What makes us good or evil? It's a simple but deeply unsettling question. One that scientists are now starting to answer. Horizon meets the researchers who have studied some of the most terrifying people behind bars - psychopathic killers. But there was a shock in store for one of these scientists, Professor Jim Fallon, when he discovered that he had the profile of a psychopath. And the reason he didn't turn out to be a killer holds important lessons for all of us. We meet the scientist who believes he has found the moral molecule and the man who is using this new understanding to rewrite our ideas of crime and punishment.

Six months after the explosions at the Fukushima nuclear plant and the release of radiation there, Professor Jim Al-Khalili sets out to discover whether nuclear power is safe. He begins in Japan, where he meets some of the tens of thousands of people who have been evacuated from the exclusion zone. He travels to an abandoned village just outside the zone to witness a nuclear clean-up operation. Jim draws on the latest scientific findings from Japan and from the previous explosion at Chernobyl to understand how dangerous the release of radiation is likely to be and what that means for our trust in nuclear power.

Adam Rutherford meets a new creature created by American scientists, the spider-goat. It is part goat, part spider, and its milk can be used to create artificial spider's web. It is part of a new field of research, synthetic biology, with a radical aim: to break down nature into spare parts so that we can rebuild it however we please. This technology is already being used to make bio-diesel to power cars. Other researchers are looking at how we might, one day, control human emotions by sending 'biological machines' into our brains.

Like many, Michael Mosley want to get fitter and healthier but can't face hours on the treadmill or trips to the gym. Help may be at hand. He uncovers the surprising new research which suggests many of us could benefit from just three minutes of high intensity exercise a week. He discovers the hidden power of simple activities like walking and fidgeting, and finds out why some of us don't respond to exercise at all Using himself as a guinea pig, Michael uncovers the surprising new research about exercise, that has the power to make us all live longer and healthier lives.

Scientists are expecting a fit of violent activity on the sun which will propel billions of tonnes of superheated gas and pulses of energy towards our planet. They have the power to close down our modern technological civilization. Horizon meets the space weathermen who are trying to predict what's coming our way, and organistions like the National Grid which are preparing for the impending solar storms.

We all like to think we are in control of our lives - of what we feel and what we think. But scientists are now discovering this is often simply an illusion. Surprising experiments are revealing that what you think you do and what you actually do can be very different. Your unconscious mind is often calling the shots, influencing the decisions you make, from what you eat to who you fall in love with. If you think you are really in control of your life, you may have to think again.

Something weird seems to be happening to our weather - it appears to be getting more extreme. In the past few years we have shivered through two record-breaking cold winters and parts of the country have experienced intense droughts and torrential floods. It is a pattern that appears to be playing out across the globe. Hurricane chasers are recording bigger storms and in Texas, record-breaking rain has been followed by record-breaking drought. Horizon follows the scientists who are trying to understand what's been happening to our weather and investigates if these extremes are a taste of whats to come.

Surgeon Gabriel Weston discovers the surprising truth about why so many people are piling on the pounds, and how to fight the fat epidemic. She discovers the hidden battles of hormones that control people's appetites, and sees the latest surgery that fundamentally changes what a patient wants to eat by altering how their brains work. Gabriel is shocked to find out that when it comes to being overweight, it is not always your fault you are fat.

Over the past year, Horizon has been behind the scenes at one of Britain's leading cancer hospitals, the Royal Marsden in London. The film follows Rosemary, Phil and Ray as they undergo remarkable new treatments - from a billion pound genetically targeted drug designed to fight a type of skin cancer, to advanced robotic surgery. We witness the breakthroughs in surgery and in scientific research that are offering new hope and helping to defeat a disease that more than one in three of us will develop at some stage of our lives.