We live on a world of wonders. A place of astonishing beauty and complexity.

We have vast oceans and incredible weather. Giant mountains and breathtaking landscapes.

If you think that this is all there is, that our planet exists in magnificent isolation, then you're wrong.

As a physicist, I'm fascinated by how the laws of nature that shaped all this, also shaped the worlds beyond our home planet.

I think we're living through the greatest age of discovery our civilisation has known.

We've voyaged to the farthest reaches of the solar system. We've photographed strange new worlds, stood in unfamiliar landscapes, tasted alien air.

And at the heart of it all is the powerhouse. A vast wonder that we greet each day.

A star that controls each and every world in its thrall. Look at that! The sun.

And when it goes, it really will be the end of us all.

This is Varanasi. For Hindus, it's one of the holiest sites in all of India.