As we make plans to travel beyond the Moon to new worlds, how are we preparing to become human extraterrestrials? Just how will we survive this trip into the unknown? Will we be able to thrive once we get to our next galactic destination? And what will we do if we make contact with intelligent life?

The blue marble we call Earth remains in large part a mystery to the 8 billion people who live on it. How did Earth come to exist, and what are the secrets of its survival? How long will humans be able to call it "home"?

For centuries, we've been fascinated by our nearest planetary neighbor, Venus, and its shimmering appearance in our night sky. But this glowing yellow orb that's about the same size as our world is covered in massive volcanoes, poisonous clouds of acid rain, and a surface temperature hot enough to melt lead. Is Venus our evil twin--or a warning about what Earth will become in the future?

From massive asteroids and deadly bursts of radiation to microscopic alien viruses, each one of these cosmic dangers may end human civilization as we know it. Can we prepare for the inevitable calamity that may be coming our way? Or are we doomed to oblivion?