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.

The search for extraterrestrial life is an age-old quest. But recent breakthroughs make today an era like no other in the history of astronomy. From the exhilarating probing of our own solar system and the Kepler mission’s astounding discovery of thousands of extrasolar planets, to the next-generation telescopes under development, the prospects for finding life beyond Earth have never been stronger.
Still, daunting hurdles remain. How can we study anything light years away, let alone a little planet? In the vast universe, where should we even start to look? Is our failure to hear any other voices in the galaxy a sign that we are special? Join leading explorers now searching the galaxy for life and intelligence on other planets—and asks, if we do find other life in the universe... what would that mean?

Mysterious lights shine out from the edge of space, brighter than a trillion suns. They had to be the brightest objects we've ever seen in the universe, putting out amounts of energy that we couldn't possibly explain. So powerful, they can incinerate planets and rip stars to pieces. These are among the most mysterious and most energetic phenomenon in the universe. They can destroy galaxies, but may also be the key to their survival. These objects are a hotbed of all kinds of crazy physics. These celestial powerhouses are called quasars, and we may owe them our very existence.

Commander Stephen Hawking and his space ship the SS Hawking encounter an alien A.I., then race to the edge of the universe, and plunge into an alternate Earth. It's an epic quest to discover the secret of the universe: The Theory of Everything. RIP. Stephen Hawking.

In the last episode, Al-Khalili turns detective, hunting for clues that show how the scientific revolution that took place in the 16th and 17th centuries in Europe had its roots in the earlier world of medieval Islam. He travels across Iran, Syria and Egypt to discover the huge astronomical advances made by Islamic scholars through their obsession with accurate measurement and coherent and rigorous mathematics.He then visits Italy to see how those Islamic ideas permeated into the west and ultimately helped shape the works of the great European astronomer Copernicus, and investigates why science in the Islamic world appeared to go into decline after the 16th and 17th centuries, only for it to re-emerge in the present day. Al-Khalili ends his journey in the Royan Institute in the Iranian capital Tehran, looking at how science is now regarded in the Islamic world

It is one of the most unnerving discoveries in space science - that most of the universe is missing. We live in a material world, so instinctively we know what normal matter is - the world around us, the planets, stars and interstellar dust. But scientists currently estimate that 95 per cent of everything in the universe is actually - one way or another - invisible.
Some of this is ordinary matter that we just can't easily see. But there's also stuff that's much more weird. For instance, there's a new kind of matter we think is out there, but whose very existence is still largely hypothetical - dark matter. And most mysteriously of all, scientists think there is an unknown form of energy pervading the universe that we know so little about, all it has so far is a name - dark energy. Embark on a tour of this invisible universe, and shows how its existence - or lack of it - will define the fate of the entire universe.