Space colonization is no longer the fodder of science fiction, it is becoming a reality. Examine the efforts underway to establish a human colony on Mars, including how they plan to grow food, recycle wastewater and introduce greenhouse gases to revive the red planet and make it more habitable for humans. Cutting-edge computer graphics are used to bring the universe down to earth to show what life would be like on Mars, and to imagine what kind of life forms might evolve in alien atmospheres.

Some of the world's leading physicists believe they have found startling new evidence showing the existence of universes other than our own. One possibility is that the universe is so vast that an exact replica of our solar system, our planet and ourselves exists many times over. These Doppelganger Universes exist within our own Universe; in what scientist now call "The Multiverse." If proof is found it will change our lives, our minds, our planet, our science and our universe.

As man moves to colonize the cosmos, the realities of sexual relationships and reproduction need to be addressed. Probe the physiological, psychological and cultural challenges of sex in space.

Right now cosmic forces prowl the universe and threaten man's very existence. They're asteroids and comets; they've left their imprint on planet Earth, literally. Initially helping to build planets through violent collisions, during this fiery bombardment period they may have even seeded Earth with water and the building blocks for life. Since the turbulent formation of the solar system, these space rocks have continued to impact Earth. Some have been so violent that they've led to mass extinctions, including one that wiped out the dinosaur. New theories suggest that asteroid and comet dust harbour deadly viruses that may have triggered some of our worst pandemics. The possibility of future collisions remains a legitimate threat yet despite their dangers, asteroids and comets may hold vital natural resources, which could actually preserve

When mankind eventually leaves the cradle of Earth and ventures forth into the uncharted territories of the cosmos, where, and what form, will our new homes take?

It sounds like a Hollywood blockbuster: a deadly asteroid is on a collision course with Earth. But in reality, it's only a matter of time before a giant space rock threatens to wipe out civilization. An asteroid took out the dinosaurs sixty-five million years ago. Are we next? This episode analyzes the threat and explores the many ways--from a nuclear bomb to ingenious new technology--that experts are proposing to stop Armageddon