Stonehenge was shaped over centuries, but to what purpose? Was it a temple to the sun, or the moon, an astronomical calendar, or a shrine to dead ancestors? Now Stonehenge may be about to give up some of its secrets. For the first time in nearly half a century a new archaeological dig the sacred stone circle. And the men who are leading the excavation are well aware of the significance of this moment.
The film exposes an investigation into a radical theory that Stonehenge, far from being a place of burial as is commonly assumed, was in fact a place of healing. The investigation takes in forensic testing of bones excavated over the past decades and hard-won permission for the first dig in 50 years at the Henge, watched live online by millions of viewers around the world. Does the theory of the healing stones bear up to modern-day forensic science?

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.

Once they were dreaded and thought to be dragons eating the sun--but modern science has dispelled mythology and we now look forward to total Solar Eclipses as one of the most spectacular phenomena in the heavens. Explore the complex movements of Earth, Moon and Sun that produce these unusual events and hear details why we may be the only intelligent beings in the known Universe to witness eclipses like we see on Earth. Man-made eclipses also figure into the science in the form of instruments called "coronagraphs." They blot out the sun and reveal its corona, uncovering secrets which, while enlightening, also warn of a disaster that could make our advanced technology crash and burn. Finally, travel into deep space, where the tiny eclipses caused by planets circling distant stars is now beginning to reveal hundreds more stars where "exoplanets" exist... perhaps even those in habitable zones like the Earth.

We face one of the greatest challenges in the history of humanity, to eliminate the fuels that have driven progress and technology for over a century, while our thirst for energy only grows. The sun is the biggest source of energy in the solar system. It's like a nuclear reactor in the sky, and it provides endless power. If we can harvest just fractions of this, it can power all our consumption. Innovators are searching for new ways to capture more of the sun’s power, and make it available through the night, everywhere.

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.

The theory of Némesis, a star that orbits the Sun and causes catastrophic events is explored. Nemesis is a hypothetical red dwarf or brown dwarf, originally postulated in 1984 to be orbiting the Sun at a distance of about 95,000 AU (1.5 light-years) somewhat beyond the Oort cloud, to explain a perceived cycle of mass extinctions in the geological record, which seem to occur more often at intervals of 26 million years.