The series highlights the major events which have shaped the Earth's history and allowed life to flourish. Follow Dr Stewart's personal journey to some of the most remote places on the planet. The atmosphere is Earth’s protective layer, cloaking us in a warm, oxygen-rich embrace and shielding us from the cold hostility of space. It acts as a natural greenhouse, keeping the Earth 51 degrees Fahrenheit warmer than it would otherwise be. Yet the atmosphere is also full of contradictions. It’s immensely powerful but at the same time highly sensitive. It’s destructive, yet it shelters us. It was created in part by the planet’s first organisms, and it continues to be essential for life.

There is a hellish planet in our solar system; covered in thick dense clouds and roasted by colossal temperatures. It will be inevitable that the Earth will someday not only be like Venus, but actually put it to shame. A billion years from now, Earth's oceans will boil off, triggering a runaway greenhouse effect, and the temperature will be so high, its all surface will melt. In the distance future, Earth could be the evil twin of Venus. To understand how our world will be destroyed we need to look at what happened to Venus.

This absolutely beautiful documentary on our World, its mystical beauty and miracles including slow motion footage of nature, animals, seasons, new life and daily beauties I've never seen nor imagined existed. The photography is sensational. The animal behaviour shown is incredible, beautiful and humorous. Even if you never have been a fan of nature documentaries, this blew you away

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.

Brian asks how, from a lifeless cosmos, it is possible that a planet can produce the more than eight million species we know of.

Huge asteroids have smashed into the earth, and turned it into an enveloped fire, uninhabitable to almost all life on the surface. The world will get hit again. It's just a matter of when. So, what should we do as a species? Should we just, like the dinosaurs, look up and die? The reasons the dinosaurs are extinct is they didn't have a space program. We do. We have the capability to perhaps escape the Earth.
Astronaut Chris Hadfield believes the only chance for human survival is to escape from Earth and build a space colony, but there are real barriers.