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 film.

Comet ISON can well be the brightest and most spectacular comet for a generation. It appeared above the eastern horizon from December 2013 as a glorious streak across the sky. ISON has been travelling towards the sun for ten thousand years and will make only one orbit through its corona before disappearing off into the outer solar system.
But as well as providing a great spectacle, ISON's tail of vaporised gas and water, hundreds of millions of kilometres long, will give insights into some of the greatest mysteries of science; it will help explain the origins of the solar system, whether earth's water was delivered on comets and even whether we are alone in the universe.

For decades some have suspected that there might be others out there, intelligent beings capable of communicating with us, even visiting our world. It might sound like science fiction, but today scientists from across the globe are scouring the universe for signals from extraterrestrials. Horizon obtained exclusive access to film researchers at the Green Bank Telescope searching for radio signals from Tabby's Star, a star so mysterious that some scientists believe it might be surrounded by a Dyson Sphere, a vast energy collector built by advanced aliens.

The car has shrunk the world, increased personal freedom and in so many ways expanded our horizons, but there is a flipside. Fumes from car exhausts have helped to destroy our environment, poisoned the air we breathe and killed us in far more straightforward ways. But all that is going to change. Enter a world where cars can drive themselves, a world where we are simply passengers, ferried about by wholesome green compassionate technology which will never ever go wrong. And it is almost here. Explore the artificial intelligence required to replace human drivers for cars themselves, peers into the future driverless world and discovers that, despite the glossy driverless PR (and assuming that they really can be made to work reliably), the reality is that it might not be all good news. From the ethics of driverless car crashes to the impact on jobs, it might be that cars are about to rise up against us in ways that none of us are expecting.

Take a look at the issues that will change the way we live our lives in the future. Hannah Fry delves into the data we have today to provide an evidence-based vision of tomorrow. With the help of science experts Hannah tries to discover whether we could ever live forever or if there will ever be a cure for cancer. She finds out how research into the human brain may one day help with mental health, and if it is possible to ever ditch fossil fuels. Hannah and her guests also discover the future of transport - and when, if ever, we really will see flying cars. She discovers whether a robot will take your job or if, as some believe, we will all one day actually become cyborgs. The programme predicts what the weather will be like and discovers if we are on the verge of another mass extinction. Hannah's tenth prediction is something she - and Horizon - are confident will definitely happen, and that is to expect the unexpected!

From the detection of gravitational waves generated in space over a billion years ago, to discoveries in genetics here on Earth, we've collected the most compelling science breakthroughs and advances of 2016. Thanks to magnificent, hard-working scientists and researchers around the world, science keeps marching ever forward. And this year saw some discoveries that are absolutely brimming with the promise of greater discoveries, breakthroughs and quality of life in the future.