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.

Is there anyone out there? Astronomers have been pointing their radio telescopes at the skies for decades trying to pick up alien signals, so far without success. But now there's a new way of looking for aliens. Hitch a ride with Dr Graham Philips as he joins astronomers trawling through the galaxy looking for signs of extra-terrestrial intelligence.

Planet Earth has been home to humankind for over 200,000 years, but with a population of 7.3 billion and counting and limited resources, this planet might not support us forever. Professor Stephen Hawking thinks the human species will have to populate a new planet within 100 years if it is to survive. With climate change, pollution, deforestation, pandemics and population growth, our own planet is becoming increasingly precarious. In this landmark film Professor Hawking, alongside engineer and radio astronomy expert Professor Danielle George and a former student, Christophe Galfard, join forces to find out if, and how, humans can reach for the stars and relocate to different planets. Travelling the globe, they meet top scientists, technologists and engineers who are working to answer our biggest questions: is there another planet out there that we could call home? How will we travel across the vast distances of space to get there? How will we survive the journey? And how will we set up a new human civilization on an alien world? Travelling the globe, they meet top scientists, technologists and engineers who are working to answer our biggest questions: is there another planet out there that we could call home? How will we travel across the vast distances of space to get there? How will we survive the journey? And how will we set up a new human civilization on an alien world? Taking in the latest advances in astronomy, biology and rocket technology from the Atacama Desert to the wilds of the Arctic, viewers will discover a whole world of cutting edge research. This programme shows that Professor Hawking’s ambition isn’t as fantastical as it sounds - and that science fiction is closer to science fact than we ever thought.

Is it humankind's greatest achievement? 12 billion miles away a tiny spaceship is leaving our Solar System and entering the void of deep space. It is the first human-made object ever to do so. Slowly dying within its heart is a plutonium generator that will beat for perhaps another decade before the lights on Voyager finally go out. But this little craft will travel on for millions of years, carrying a Golden Record bearing recordings and images of life on Earth. In all likelihood Voyager will outlive humanity and all our creations. It could be the only thing to mark our existence. Perhaps some day an alien will find it and wonder. The story of Voyager is an epic of human achievement, personal drama and almost miraculous success. Launched 16 days apart in Autumn 1977, the twin Voyager space probes have defied all the odds, survived countless near misses and almost 40 years later continue to beam revolutionary information across unimaginable distances.

The deep is perhaps the most hostile environment on earth, at least to us - a world of crushing pressure, brutal cold and utter darkness. We have barely begun to explore it, and yet it is the largest living space on the planet. Scientists already think that there is more life in the deep than anywhere else on earth. This episode takes us on an epic journey into the unknown, a realm that feels almost like science fiction. We discover alien worlds, bizarre creatures and extraordinary new behaviours never seen before. We encounter savage hordes of Humboldt squid hunting lanternfish in the depths and coral gardens flourishing in absolute darkness, with more species of coral to be found in the deep than on shallow tropical reefs. Narrated by David Attenborough.

The hunt for aliens is on! After a distinguished career in cosmology Professor Martin Rees, the astronomer royal, has taken up the search for extra-terrestrials. Looking for aliens is no longer science fiction - it is a question that's engaging some of the greatest minds in science." As our knowledge of the universe has increased, we're getting closer to answers. Many scientists now think we live in galaxy with a billion Earth-like planets, many of which may be teeming with life. But what kind of life? Has anything evolved into beings we could communicate with? This film gets inside the minds of the scientists considering one of the most exciting and profound questions we can ask - are we alone in the universe? Professor Rees thinks we may have our idea of what an alien is like all wrong. If he's right, it's not organic extra-terrestrials we should look for, it's machines.