Dark energy - the mysterious force that is unexpectedly causing the universe's expansion to speed up. The effects of dark energy were discovered in 1998 but physicists still don't know what it is. Worse, its very existence calls into question Albert Einstein's general theory of relativity - the cornerstone of modern physics. The hunt for the identity of dark energy is on". Experiments on earth and in space generate data that might provide a clue, but there are also hopes that another Einstein might emerge - someone who can write a new theory explaining the mystery of the dark energy.

The oceans define the earth. They are crucial to life and we used to think that they were unique to our blue planet. But we were wrong. It has recently been discovered that there are oceans all over our solar system, and they are very similar to our own. And now scientists are going on an epic journey in search of new life in places that never seemed possible. Nasa is even planning to dive to the depths of a strange, distant ocean in a remarkable submarine. Discover that the hunt for oceans in space is marking the dawn of a new era in the search for alien life.

Legendary master filmmaker Werner Herzog chronicles the virtual world from its origins to its outermost reaches, exploring the digital landscape with the same curiosity and imagination he previously trained on earthly destinations. Herzog leads viewers on a journey through a series of provocative conversations with cyberspace pioneers and prophets such as PayPal and Tesla co-founder Elon Musk, Internet protocol inventor Bob Kahn, and famed hacker Kevin Mitnick, that reveal the ways in which the online world has transformed how virtually everything in the real world works - from business to education, space travel to healthcare, and the very heart of how we conduct our personal relationships.

From the detection of gravitational waves generated in space over a billion years ago, to discoveries in genetics here on Earth, we've collected the most compelling science breakthroughs and advances of 2016. Thanks to magnificent, hard-working scientists and researchers around the world, science keeps marching ever forward. And this year saw some discoveries that are absolutely brimming with the promise of greater discoveries, breakthroughs and quality of life in the future.

Commander Stephen Hawking pilots his space ship the SS Hawking on the journey of a lifetime, zooming from black holes to the Big Bang, Saturn to Santa Barbara. After all, why should astronauts have all the fun?

Dan Snow uncovers the lost Vikings in America with space archaeologist Dr Sarah Parcak. Sarah uses satellites 383 miles above the earth to spot ruins as small as 30cm buried beneath the surface. As Sarah searches for Viking sites from Britain to America, Dan explores how they voyaged thousands of miles when most ships never left the shoreline. He also tracks their expansion west, first as raiders and then as settlers and traders throughout Britain and beyond to Iceland and Greenland. In North America they excavate what could be the most westerly Viking settlement ever discovered.