In 1977 NASA launched the space probe Voyager 1 which is now travelling at 40,000mph and has left the Solar System. In 1980 Voyager passed Saturn and Carl Sagan proposed that it take a picture of earth in the far distance – this picture became known as the Pale Blue Dot. Sagan said:

We succeeded in taking that picture, and, if you look at it, you see a dot. That’s here. That’s home. That’s us. On it, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there – on a mote of dust, suspended in a sunbeam.

…To my mind, there is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly and compassionately with one another and to preserve and cherish that pale blue dot, the only home we’ve ever known.

In the BBC series Forces of Nature with Professor Brian Cox, the final episode The Pale Blue Dot describes how light and colours enable astronomers to explore the universe and search for life. In the final words to the programme Prof. Cox said:

Astronomy turns data into dreams. Dreams of worlds of ice and snow. Dreams of worlds with hemispheres of perpetual day and permanent night. Dreams of worlds with moons and moonbows. And perhaps, just perhaps alien astronomers observing the light tracking through the atmosphere of our blue world and dreaming of us.

Our ability to use our imagination and transport ourselves to other places, other planets has been used by people ever since they began looking into the night sky. Our imaginations took us into space long before Yuri Gagarin first orbited the earth and Voyager began exploring our Solar System.