We feel it every moment of our lives but for physicists, gravity is the longest running unsolved mystery of the universe. Why do all objects that have mass pull on one another? Cutting-edge theories are proposing unexpected answers: Gravity could be another force in disguise, a thermodynamic mirage, or even, a shadow of a hidden holographic universe. If so, the force that holds us to the surface of the earth, and holds the earth in orbit around the sun, may be a trick of the mind. We feel it, but it may not be real. Is Gravity an Illusion?

In this second episode we travel from January to the March equinox. Kate Humble gets closer to the Sun than she has ever been before, whilst Helen Czerski visits a place that gets some of the biggest and fastest snowstorms on Earth.

How does light escape from the sun? We take a journey from the center of the sun, following the path of light. We witness its fiery birth from in the core, its 430,000 mile battle against gravity and magnetism, and its escape from the solar surface.

Beneath Jupiter's swirling clouds lie our solar system's deepest secrets: from its violent youth, through the birth of life to the death of the sun. Now, scientists are unlocking these secrets and discovering that every living thing exists thanks to Jupiter.

Perhaps the most mysterious structure on Earth, Stonehenge has stood on a plain in Southern England for 5000 years. Its foundations predate the Great Pyramids. It is one of mankind's most ancient mysteries. Why is it here? Is it a temple? A burial ground? A place for sacrifice? Or could the mystery of Stonehenge be revealed in its builders' desire to explore the unknown heavens and touch the universe? Using the cutting-edge computer-generated imagery that takes us into deep space, we'll also go inside a virtual Stonehenge to see what the ancients saw and push this prehistoric marvel to give up its age-old secrets.
In this episode we explore the possibility that this was a prehistoric astronomical observatory. Here ancient astronomer priests may have divined the complex movements of the Sun and Moon, recognizing patterns that would not be discovered elsewhere for thousands of years. The primitive Shamans may have also been the first astronomers to predict eclipses.

In 2006, an Iceland-based outfit called The Sunshine Press launched the website WikiLeaks.org. As run by Australian Internet activist Julian Assange, the site's mandate involved regularly publishing top-secret documents and covert information, often regarding governments and their respective military operations". As might be expected, this set off a firestorm between those who admired the organization's bravado and resourcefulness, and those who argued, not unjustly, that the dissemination of data regarding such events as the U.S. war in Afghanistan could put untold numbers of lives at risk. In We Steal Secrets, Gibney relays the story of the WikiLeaks website from the inside, and moves beyond black and white to penetrate a complex network of activity guided by courage and idealism but also allegedly guilty of ethical insensitivity and hypocrisy. Acclaimed documentarian Alex Gibney (Enron: The Smartest Guys in the Room) takes the reins for this no-holds-barred look at one of the most unusual phenomena of early 21st century media.