When man finally broke free of the Earth's gravitational pull the dream of travelling to other planets became a reality. Today scientists are proposing a bizarre array of technologies in the hope of travelling faster through space: from space craft sporting sails that catch laser beams, to propulsion engines powered by a bizarre entity known as anti-matter. Finally explore the science behind the seemingly fanciful notion of warp-drive and a theoretical particle that can travel faster than light.

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 black hole at the centre of the Milky Way is getting ready to feast. A gas cloud three times the size of our planet has strayed within the gravitational reach of our nearest supermassive black hole. And across the globe, telescopes are being trained on the heart of our Milky Way galaxy, some 27,000 light years from Earth, in the expectation of observing this unique cosmic spectacle. For cosmic detectives across the Earth, it is a unique opportunity. For the first time in the history of science, they hope to observe in action the awesome spectacle of a feeding supermassive black hole.

Travel to heart of the Sun, our star, a cauldron of superheated gases that writhe and contort along immense magnetic field lines. Discover how even life itself is forged in the heart of stars. We are made of stardust.

The final episode explores dinosaurs' extraordinary ability to survive. Featured dinosaurs include the bizarre magyarosaurus, which lived in the shadow of the biggest flying animal - hatzegopteryx - and showed an amazing adaptation to island life; and the weird nothronychus, a carnivore that gave up meat eating. This astonishing capacity to evolve into ever more diverse and bizarre forms meant that dinosaurs not only spread throughout the world, but also dominated life upon it for more than 160 million years. It was only an unprecedented extraterrestrial event that finally saw the end of planet dinosaur.

Sagan discusses comets and asteroids as planetary impactors, giving recent examples of the Tunguska event and a lunar impact described by Canterbury monks in 1178. It moves to a description of the environment of Venus, from the previous fantastic theories of people such as Immanuel Velikovsky to the information gained by the Venera landers and its implications for Earth's greenhouse effect. The Cosmos Update highlights the connection to global warming.