Unidentified objects witnessed by military pilots. Extraterrestrial probes, flying through our solar system. And a potential alien home world that may be hidden in the darkness of space.

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?

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"?

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?

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?

We humans want to boldly go into uncharted territories to make new discoveries. As the next era of space exploration begins, what will we find when we reach other planets?

Earth's moon is only one of hundreds in the solar system—each of them a mysterious and often bizarre world. Could alien moons offer a key to exploring outer space and perhaps even finding a new home for humanity?

Humanity has worshipped the Sun since the beginning of time, and yet even with our modern technology, we still know so little about it.