Why humanity's survival may depend on colonizing Mars

Recently, NASA disclosed it was monitoring a 480-meter asteroid that could collide with the Earth sometime within the next four decades. British astronomers have been even more stark in speaking of the likelihood that a space rock of large enough size could create pandemonium around the world.

Asteroids “cross our orbit frequently, and we know we’re going to get hit again,” Greene said, underscoring that factors such as trajectory and conditions in space can determine whether asteroids hit the earth or pass it by.

However, “it’s not a matter of if, but when. This planet won’t have a planet killer hit it for many hundreds of years, but it will happen,” he added.

The panoply of risks makes it important to seek out viable alternatives to ensure humanity’s survival. Likening the idea of an extraterrestrial colony to a computer’s external hard drive, Greene told CNBC that “If we’re going to live as a species, we’re going to have to ‘back up’ in other places … and that place is Mars.”