The last episode in the series examines how humans perceive and experience time, investigating the internal body clock which tells people when to eat, drink, sleep and relax. The importance of accurately measuring time is explored in relation to human evolution, and there's a debate about whether mankind will ever be able to travel between past, present and future.
Antarctica is the last great wilderness. It's the coldest, windiest, driest and most isolated place on Earth. And every winter, for over three months of the year, the sun never rises. But it's also home to the British Antarctic Survey's Halley Research Station. A veteran of living and working at Halley in the early eighties, BBC weatherman Peter Gibbs makes an emotional return to the place he once called home. A place that, during his time, was key to the discovery of the ozone hole. The journey starts with an arduous 12-day, 3000-mile voyage onboard the RRS Ernest Shackleton. Once on the ice shelf, Peter is delighted to finally arrive at the futuristic research station and marvels at the cutting edge science being done at Halley today. From vital discoveries about how our lives are vulnerable to the sun's activities, to studying interplanetary travel and the threat of man-made climate change. But Peter's journey is also something of a rescue mission. The research station's home is a floating ice shelf that constantly moves and cracks, and the ice shelf has developed a chasm that could cast Halley adrift on a massive iceberg.
We are all at the mercy of the Sun. Its glowing disc sustains nearly all life on Earth. But the Sun also holds a dark secret: someday, our aging, expanding star will bathe the Earth in a fiery holocaust. Everything we know will turn to hot, bubbling, plasma.
Dr Alice Roberts asks one of the great questions about our species: are we still evolving? There's no doubt that we're a product of millions of years of evolution. But thanks to modern technology and medicine, did we escape Darwin's law of the survival of the fittest? Alice follows a trail of clues from ancient human bones to studies of remarkable people living in the most inhospitable parts of the planet and the frontiers of genetic research, to discover if we are still evolving - and where we might be heading.