The second part, Nothing, explores science at the very limits of human perception, where we now understand the deepest mysteries of the universe lie. Professor Jim Al-Khalili sets out to answer one very simple question - what is nothing? His journey ends with perhaps the most profound insight about reality that humanity has ever made. Everything came from nothing. The quantum world of the super small shaped the vast universe we inhabit today, and Jim can prove it.

These scientists are part of a global race. It's been running for over a decade... to build a mythical machine, the holy grail of calculations - a quantum computer. Remarkably, first-generation quantum computers have started to appear. Indeed, earlier this year, Google bought one. The D-Wave 2.

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.

Commander Stephen Hawking takes another journey in his space ship, the SS Hawking, this time to Venus, the Sun and out to the Eagle Nebula...but things don't always go according to the flight plan...

Electricity is not just something that creates heat and light, it connects the world through networks and broadcasting. After centuries of man's experiments with electricity, the final episode tells the story of how a new age of real understanding dawned - how we discovered electric fields and electromagnetic waves. Today we can hardly imagine life without electricity - it defines our era. As our understanding of it has increased so has our reliance upon it, and today we are on the brink of a new breakthrough, because if we can understand the secret of electrical superconductivity, we could once again transform the world.

Al-Khalili travels to northern Syria to discover how, a thousand years ago, the great astronomer and mathematician Al-Biruni estimated the size of the earth to within a few hundred miles of the correct figure. He discovers how medieval Islamic scholars helped turn the magical and occult practice of alchemy into modern chemistry. In Cairo, he tells the story of the extraordinary physicist Ibn al-Haytham, who helped establish the modern science of optics and proved one of the most fundamental principles in physics - that light travels in straight lines. Prof Al-Khalili argues that these scholars are among the first people to insist that all scientific theories are backed up by careful experimental observation, bringing a rigour to science that didn't really exist before.