For centuries, the precise workings of gravity have confounded the greatest scientific minds - from Newton to Faraday and Einstein - and the idea of controlling gravity has been seen as little more than a fanciful dream. Yet in the mid 1990s, UK defence manufacturer BAE Systems began a ground-breaking project code-named Greenglow. Nasa was simultaneously running its own Breakthrough Propulsion Physics Project". It was concerned with potential space applications of new physics, including concepts like 'faster-than-light travel' and 'warp drives'. Looking into the past and projecting into the future, Horizon explores science's long-standing obsession with the idea of gravity control. It looks at recent breakthroughs in the search for loopholes in conventional physics and examines how the groundwork carried out by Project Greenglow has helped change our understanding of the universe. Gravity control may sound like science fiction, but the research that began with Project Greenglow is very much ongoing, and the dream of flying cars and journeys to the stars no longer seems quite so distant.

Meet Perseverance, NASA's latest rover, as it heads to Mars to answer one question: did life exist on the red planet? On the way, it will lay the foundation for human exploration of our closest neighbour.
Today, Mars is hostile to life. It's too cold for water to stay liquid on the surface, and the thin atmosphere lets through high levels of radiation, potentially sterilizing the upper part of the soil. But it wasn't always like this. Some 3.5 billion years ago or more, water was flowing on the surface. It carved channels still visible today and pooled in impact craters. A thicker carbon dioxide atmosphere would have blocked more of the harmful radiation. The Mars 2020/Perseverance rover is designed to better understand the geology of Mars and seek signs of ancient life. The mission will collect and store a set of rock and soil samples that could be returned to Earth in the future. It will also test new technology to benefit future robotic and human exploration of Mars, as the Ingenuity Helicopter.

Professor Brian Cox tackles some of the most challenging and intriguing questions facing science. He looks back on a decade of discovery and towards the next space frontier.
Brian believes we are at the start of a new age of space travel, where space flight is on the verge of becoming routine. In this episode, he explores the latest science and takes a new look at his old films and asks: how far can we go in our exploration of the cosmos?

This documentary journeys with the scientists into the heart of a giant. Juno is the Nasa mission designed to peer through Jupiter's swirling clouds and reveal the wonders within. By projecting a 70-foot-wide, life-size Juno on a Houston rooftop, Scott Bolton, head of Juno, 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.' 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.
Under the extreme conditions of Jupiter thousands of miles under the surface, 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.

The centre of our galaxy is home to an invisible monster of unimaginable power – a supermassive black hole named Sagittarius A star, with four million times the mass of the Sun. Recent astronomical breakthroughs have confirmed not only that black holes like Sagittarius A star exist, but that these bizarre invisible objects may be the ultimate galactic protagonists.
Stunning CGI takes us back to witness the fiery origins of our galaxy’s black hole 13.6 billion years ago, when the early universe was home to colossal blue stars, and when they ran out of fuel, they collapsed under their own enormous mass, crushing down into an object so small and so dense it punched a hole in the fabric of the universe. Over billions of years, Sagittarius A star feasted on nearby gas, stars, and through cataclysmic mergers with other black holes. A breakthrough discovery by Nasa’s Fermi gamma-ray telescope has shown that our black hole had the power to sculpt the entire galaxy, creating vast bubbles of gas above and below our galaxy and even protecting stars systems as ours.
In a mind-bending conclusion, Brian Cox reveals how our modern understanding of black holes is challenging our concepts of reality to the breaking point. In trying to understand the fate of objects that fall into Sagittarius A star, scientists have come to a stunning conclusion: space and time, concepts so foundational to how we experience the world around us, are not as fundamental as we once thought.

Almost everything we know today about the beautiful giant ringed planet comes from Cassini, the NASA mission that launched in 1997 and arrived at Saturn in 2004. Since then, the space probe has been beaming home miraculous images and scientific data, revealing countless wonders about the planet, its rings and 62 moons - including some that could harbor life. When the mission approached its final days, it attempted one last set of daring maneuvers - diving between the innermost ring and the top of Saturn's atmosphere.
Aiming to skim less than 2000 miles above the cloud tops, no spacecraft has ever gone so close to Saturn, and hopes were high for incredible observations that could solve major mysteries about the planet's core. But such a daring maneuver comes with many risks and is no slam dunk. In fact, slamming into rocks in the rings is a real possibility. Join NASA engineers for the tense and triumphant moments as they find out if their bold re-programming has worked, and discover the wonders that Cassini has revealed over the years.