Questions are raised about the search for intelligent life beyond the Earth, with UFOs and other close encounters refuted in favor of communications through SETI and radio telescope such as the Arecibo Observatory. The probability of technically advanced civilizations existing elsewhere in the Milky Way is interpreted using the Drake equation and a future hypothetical Encyclopedia Galactica is discussed as a repository of information about other worlds in the galaxy. The Cosmos Update notes that there have been fewer sightings of UFOs and more stories of abductions, while mentioning the META scanning the skies for signals.

Are we alone? SETI--the Search for Extraterrestrial Intelligence--is a privately funded project using radio telescopes and optical telescopes to scan the stars for signals.

Our galaxy is one of hundreds of billions in the universe. View of universe through the Hubble telescope and go back almost all the way to the Big Bang.

It's a mystery mankind has struggled to solve since the beginning of history - is space infinite or might there be great cosmic border where everything ends? Groundbreaking cosmology and state of the art space telescopes, now suggest the Universe has a finite size and a unique shape. If this is true, there must be an edge to the Universe, and beyond that edge, there could exist a world beyond our wildest dreams.

Around the world, a new generation of astronomers are hunting for the most mysterious objects in the universe. Young stars, black holes, even other forms of life. They have created a dazzling new set of super-telescopes that promise to rewrite the story of the heavens. This film follows the men and women who are pushing the limits of science and engineering in some of the most extreme environments on earth. But most strikingly of all, no-one really knows what they will find out there.

In this episode, Helen seeks out the colours that turned planet Earth multicoloured. To investigate the essence of sunlight Helen travels to California to visit the largest solar telescope in the world. She discovers how the most vivid blue is formed from sulfur atoms deep within the Earth's crust and why the presence of red ochre is a key sign of life. In gold, she discovers why this most precious of metals shouldn't even exist on the surface of the planet and in white, Helen travels to one of the hottest places on Earth to explore the role salt and water played in shaping planet Earth.