What is the universe made of? If you answered stars, planets, gas and dust, you'd be dead wrong. Thirty years ago, scientists first realized that some unknown dark substance was affecting the way galaxies moved. Today, they think there must be five times our understanding of the universe and the nature of reality itself has drastically changed over the last 100 years - and it's on the verge of another seismic shift. In a 17-mile-long tunnel buried 570 feet beneath the Franco-Swiss border, the world's largest and most powerful atom smasher, the Large Hadron Collider, is powering up. Its goal is nothing less than recreating the first instants of creation, when the universe was unimaginably hot and long-extinct forms of matter sizzled and cooled into stars, planets, and ultimately, us. These incredibly small and exotic particles hold the keys to the greatest mysteries of the universe. What we find could validate our long-held theories about how the world works and what we are made of -- or, all of our notions about the essence of what is real will fall apart.

What if aliens landed on Earth? Much of science fiction explores the moment of first contact – what will people do when the aliens land? From H. G. Wells’ pioneering The War of the Worlds to Independence Day, Men in Black, and District 9, Invasion deals with our fears of alien invasions of earth. David Tennant explains the appeal of Doctor Who’s Daleks and Cybermen while John Carpenter and Chris Carter explore the rich appeal of the paranoia fuelled by hidden aliens with The Thing and The X-Files. It also asks, what if the monsters were our own creation? With the aid of rarely seen animation tests, Phil Tippett takes us behind the scenes in the creation of the dinosaurs of Jurassic Park. But not all invasions are hostile. Peter Coyote and Richard Dreyfuss discuss the creation of Spielberg’s spellbinding classics E.T. the Extra-Terrestrial and Close Encounters of the Third Kind. There is more than one kind of invasion.

This new feature-length biographical film tells the extraordinary and dramatic story of the planet's most famous living scientist, told for the first time in his own words and by those closest to him. Made with unique access to his private life, this is an intimate and moving journey into Stephen Hawking's past and present. Interviewees include Stephen Hawking's sister Mary, his ex-wife Jane, carers and students, as well as colleagues such as Roger Penrose, plus Apollo astronaut Buzz Aldrin, actors Benedict Cumberbatch and Jim Carrey, and Sir Richard Branson This inspirational portrait of an iconic figure relates Hawking's incredible personal journey from boyhood underachiever to scientific genius and multi-million-selling author. And it charts how he overcame being diagnosed with motor neurone disease - and being given just two years to live - to make amazing scientific discoveries and become a symbol of triumph over adversity. Born exactly 300 years after the death of Galileo, Hawking grew up in a family some regarded as eccentric. Always asking questions, he was nicknamed 'Einstein' at school. Hawking blossomed at Oxford, although he only spent an hour a day studying. He noticed that he was becoming clumsy and fell over for no apparent reason. He was diagnosed with motor neurone disease, but nevertheless started a family and embarked on his academic career, finding himself at the heart of a searing scientific debate about the origins of the universe. And as he lost the use of his body, Hawking had to find new ways to think. He went on to write the huge bestseller A Brief History of Time, and the film reveals the high and lows of his resulting fame and fortune.

The climate is changing faster than ever, which is why 'fix our climate' is one of the five goals of the Earthshot Prize. Prince William, Sir David Attenborough and Christiana Figueres highlight inspiring and often unexpected solutions to the challenge. In this film, we'll explain the scale of the problem posed by climate change and will introduce you to some amazing people already working on climate crisis. One of these three finalists will win the Earthshot Prize and get the platform and resources they need to scale their ground-breaking work. Nine more solutions for fixing our climate will receive the same support over the course of this decade.

Are the rings of Saturn a real celestial phenomenon or merely a cosmic Illusion? Technology allows the experts to get closer to the furthest planet visible to the naked eye. Old questions are answered and new ones arise. Does Saturn hold the key to Earth's weather and will one of its moons supply us with all the oil we'll ever need?

The episode, devoted to the planet Mars, begins with scientific and fictional speculation about the Red Planet during the late nineteenth and early twentieth centuries (H. G. Wells' The War of the Worlds, Edgar Rice Burroughs' science fiction books, and Percival Lowell's false vision of canals on Mars). It then moves to Robert Goddard's early experiments in rocket-building, inspired by reading science fiction, and the work by Mars probes, including the Viking, searching for life on Mars. The episode ends with the possibility of the terraforming and colonization of Mars and a Cosmos Update on the relevance of Mars' environment to Earth's and the possibility of a manned mission to Mars.