Physics

We move around in space, but we are stuck in a prison of time moving ever forwards. Einstein said, 'The distinction between past, present and future is only a stubbornly persistent illusion.' Is our experience of the ticking clock merely a trick of the mind? Could science ever make the clock move backwards? Experiments in quantum physics are showing that the future influences the present: what happens later limits the choices we think we have now. The laws of physics say visiting or talking to ourselves in the past is possible – but changing history once we get there is not.

Professor Jim Al-Khalili discovers the intriguing story of how we discovered the rules that drive the universe. Energy is vital to us all, but what exactly is energy? In attempting to answer this question Jim investigates a strange set of laws that link together everything from engines to humans to stars. It turns out that energy, so critical to daily existence, actually helps us make sense of the entire universe.

Just under 200 years ago scientists discovered something profound, that electricity is connected to another of nature's most fundamental forces - magnetism. In the second episode, Jim discovers how harnessing the link between magnetism and electricity would completely transform the world, allowing us to generate a seemingly limitless amount of electric power which we could utilise to drive machines, communicate across continents and light our homes. This is the story of how scientists and engineers unlocked the nature of electricity in an extraordinary century of innovation and invention.

Just outside Paris, inside a hi-tech vault, and encased in three vacuum-sealed bell jars, rests a small metallic cylinder about the diameter of a golf ball. It may not look like much, but it is one of the most important objects on the planet. It affects nearly every aspect of our lives including the food we eat, the cars we drive, even the medicines we take. It is the Kilogramme, the base unit of mass in the International System of Units. Yet over time, its mass has mysteriously eroded by the weight of an eyelash. A change that, unbeknownst to most, unleashed a crisis with potentially dire consequences.
The film follows the ensuing high-stakes, two-year race to redefine the weight of the world, and tells the story of one of the most important objects on the planet.

The human eye is a remarkable piece of precision engineering, but it is also extremely limited. Beyond the narrow range of light that makes up the familiar colours of the rainbow is a vast spectrum of light, entirely unseen. Richard Hammond does just that, using ground-breaking new imaging technologies to take the viewer on a breath-taking journey of discovery beyond the visible spectrum, seeing the world, quite literally, in a whole new light. From death-defying aerial repairmen in the United States using ultraviolet cameras to seek out an invisible force that lurks unseen on power lines, to German scientists unlocking the secrets of animal locomotion with the world's most powerful moving x-ray camera, to infrared cameras that can finally reveal the secrets within a humble beehive, he shows how new technologies are letting us see our world anew.

How and when will the Universe end? Gravity and dark matter are poised to annihilate the Universe in a big crunch. Expansion and dark energy may tear it apart. Or, a phase transition could kill us tomorrow in a cosmic death bubble.