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.

It is time to see if personalised dieting will work in normal life. The volunteers have been given one of three diets to follow - based on their genes, their hormones and their psychology. But now they are back at home, trying to stick to their personalised diets with all the stresses and temptations of real life. Dr Chris van Tulleken and Professor Tanya Byron discover how our genetic makeup can make temptation difficult to resist, how understanding the brain reveals what makes us comfort eat and what science can tell us about why we make disastrous food choices.

As almost all animal inhabitants of Antarctica are forced to migrate north, the sea underneath the frozen ice still provides a home to many specially adapted fish whose cells are protected from freezing through an 'antifreeze' liquid. Many of them feed on the faeces of other animals. The most notable larger animal that does not migrate north is perhaps the Weddell Seal, which can be found as close as 1300 kilometres to the pole. Groups of seals tear holes into the ice to dive for food and come up to breathe. The females come back to the ice to give birth. This episode also describes primitive plant life such as lichen, which can still be found on the continent in winter, even in the extremely dry and permanently frozen valleys conditions under which dead animals can lie frozen for many centuries without decomposing. It details the life of the Emperor Penguin, 'the only birds to lay their eggs directly on ice'. While other animals retreat, Emperors migrate not just to the ice, but into the Antarctic continent. The females lay eggs which are incubated by the males under the harshest conditions on Earth (huddling closely together for warmth), while the females return to the sea.

Take another walk on the wild side with our favourite pets. Extraordinary photography reveals their hidden senses and secret communication skills. Dogs take a car trip through Paris, using their legendary sense of smell to show us a very different city. A hamster uses his remarkable senses to stage a great escape and then deploys more navigational talents to find his way home. Cats become intoxicated on the scent of a plant and suffer the consequences. A budgie shows his hidden charms to his mate as, under UV light, his crown and cheeks positively glow. Goldfish reveal secret senses that can detect the slightest water movement. A guinea pig gives birth and the newborns receive surprising care from their father. In South America, where guinea pigs have lived with people for 7,000 years, they express the true meaning of their entertaining calls. When we groom a horse we speak their language, but horses use ears to communicate in ways that we are rarely aware of. In Japan cats show their secret messages and in Peru dogs reveal the hidden signs that allow them to communicate across a city. Packed with extraordinary facts and wild behaviour - you'll never look at your pet in the same way again

There could be an undiscovered species on Earth unlike anything we’ve ever known. Not in the ocean, but the ocean itself! Its body spans thousands of miles; its heart beats with a one-thousand-year pulse. It could even have an immune system capable of annihilating all other life on earth. Just as our bodies function through the interaction of water with individual cells, including bacteria and other microorganisms, the ocean’s residents might collectively form a super-organism. A recent discovery suggests the ocean is a living being capable of thought. If so, what is the ocean thinking about us?

When we look up into the sky it appears we live in a universe that is filled with light. But scientists are now certain there is far more matter in the dark portions of our universe that we can’t see or touch. There’s something hiding in the shadows. Cosmologists agree that 'dark matter' has helped shape our Universe, but now they need to figure out what dark matter is. What’s going on in this hidden world? Could it have formed its own dark stars, planets, and even life forms? Could this Shadow Universe threaten our world of light?