There is no greater test for life than winter, as temperatures plummet to 70 below and winds reach 200kph. Darkness and ice extend across the polar regions and only a few remarkable survivors gamble on remaining. We join a female polar bear trekking into the Arctic mountains to give birth as the first blizzards arrive. Out on the frozen ocean, the entire world's population of spectacled eider ducks brave the winter in a giant ice hole kept open by ferocious currents. Arctic forests transform into a wonderland of frost and snow - the scene of a desperate and bloody battle between wolf and bison, but also where a remarkable alliance between raven and wolverine is made. Beneath the snow lies a magical world of winter survivors. Here tiny voles dodge the clutches of the great grey owl, but cannot escape the ultimate under-show predator - the least weasel. Midwinter and a male polar bear wanders alone across the dark, empty icescape. Below the snow, polar bear cubs begin life in an icy den while fantastical auroras light the night skies above. In Antarctica, we join male emperor penguins in their darkest hour, battling to protect precious eggs from fierce polar storms. Weddell seals escape to a hidden world of jewel-coloured corals and alien-looking creatures but frozen devastation follows as sinister ice stalactites reach down with deadly effect.

The documentary series reveals the extraordinary riches and wonders of the Polar Regions that have kept people visiting them for thousands of years. Today, their survival relies on a combination of ancient wisdom and cutting-edge science. Most Arctic people live in Siberia, either in cities like Norilsk - the coldest city on earth - or out on the tundra, where tribes like the Dogan survive by herding reindeer, using them to drag their homes behind them. On the coast, traditional people still hunt walrus from open boats - it is dangerous work, but one big walrus will feed a family for weeks. Settlers are drawn to the Arctic by its abundant minerals; the Danish Armed Forces maintain their claim to Greenland's mineral wealth with an epic dog sled patrol, covering 2,000 miles through the winter. Above, the spectacular northern lights can disrupt power supplies so scientists monitor it constantly, firing rockets into it to release a cloud of glowing smoke 100 kilometres high. In contrast, Antarctica is so remote and cold that it was only a century ago that the first people explored the continent. Captain Scott's hut still stands as a memorial to these men. Science is now the only significant human activity allowed; robot submarines are sent deep beneath the ice in search of new life-forms, which may also be found in a labyrinth of ice caves high up on an active volcano. Above, colossal balloons are launched into the purest air on earth to detect cosmic rays. At the South Pole there is a research base designed to withstand the world's most extreme winters. Cut off from the outside world for six months, the base is totally self-sufficient, even boasting a greenhouse.

It begins by examining the shift in the language and sound of music from the melodies and harmonies of giants such as Mozart, Haydn and Brahms into the fragmented, abstract, discordant sound of the most radical composers of the new century - Schoenberg, Webern, Stravinsky and beyond. It examines how this new music was a response to the huge upheaval in the world at the start of the 20th century, with its developments in technology, science, modern art and the tumult of the First World War. Featuring performances of some of the key works of the period, performed by the London Sinfonietta, members of the Aurora Orchestra and composer and pianist Timothy Andres, the story of this episode in music history is brought to life through the contributions of the biggest names in modern classical music, among them Steve Reich, John Adams, Michael Tilson Thomas, Pierre Boulez, George Benjamin and Alex Ross, music critic of the New Yorker.

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.

A variety of cosmic events have both helpful and harmful effects on life on Earth. From the beauty of the Aurora Borealis and rainbows to the dangers of UV radiation and cosmic rays, from the miracle of photosynthesis to the thrill of a meteor shower, this episode explores how the effects generated by the sun and other extra-solar sources can literally get under our skin, scramble our technology, make life possible and threaten our existence all at the same time

In the last few years, the Red Planet has yielded up many new clues that life may have once existed there...and may even exist there today. There is now have proof that water once flowed on the surface, that Mars once had lakes, and that the frozen poles are mostly water, not carbon dioxide as previously thought. Mars has snow--an aurora--and lightning generated by dust storms. Most intriguing of all are the seasonal plumes of methane that just may point to bacteria living below the surface.