Imagine a world where dinosaurs still walk the earth. A world where the Germans won World War II and you are president of the United States. Imagine a world where the laws of physics no longer apply and where infinite copies of you are playing out every storyline of your life. It sounds like a plot stolen straight from Hollywood, but far from it. This is the multiverse. Until very recently the whole idea of the multiverse was dismissed as a fantasy, but now this strangest of ideas is at the cutting edge of science. And for a growing number of scientists, the multiverse is the only way we will ever truly make sense of the world we are in. Horizon asks the question: Do multiple universes exist? And if so, which one are we actually in?
Carl Sagan opens the program with a description of the cosmos and a "Spaceship of the Imagination" (shaped like a dandelion seed). The ship journeys through the universe's hundred billion galaxies, the Local Group, the Andromeda Galaxy, the Milky Way, the Orion Nebula, our Solar System, and finally the planet Earth. Eratosthenes' successful calculation of the circumference of Earth leads to a description of the ancient Library of Alexandria. Finally, the "Ages of Science" are described, before pulling back to the full span of the Cosmic Calendar. Note: This revised version of the series adds an introduction by Ann Druyan, in which she discusses some of the changes that occurred in the years after its broadcast.
Our first steps into space were leaps into the unknown. Outer space is still the most hostile environment ever encountered, but someday, we may be forced to leave earth in order to save our species. The question now is whether human ingenuity can overcome the human body’s limitations.
Now that gravitational waves are definitely a thing, it’s time to think about some of the crazy things we can figure out with them. In some cases we’re going to need a gravitational wave observatory - in fact, we've already built one.
Discover how beauty and order in Earth's cosmic backyard was formed from nothing more than a chaotic cloud of gas. Chasing tornados in Oklahoma, Professor Brian Cox explains how the same physics that creates these spinning storms shaped the young solar system. Out of this celestial maelstrom emerged the jewel in the crown, Brian's second wonder - the magnificent rings of Saturn.