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" Another mass extinction is coming. From the fossil record, we know that a major extinction event occurs on Earth about once every 100,000 years. The worst one was the Permian\u2013Triassic extinction about 252 million years ago, which wiped out an estimated 96 percent of all marine life and 70 percent of terrestrial vertebrate species. In a new installment of PBS&amp;#039;s wonderful online series Space Time, host and astrophysicist Matthew O&amp;#039;Dowd teams up with physics-degree-holding science fiction writer Neal Stephenson to discuss some of the ways we could face our doom\u2014asteroids, major volcanic events, nearby supernovae\u2014and the best ways we could prepare to hopefully save our species from annihilation.         One of the best ways to safeguard against human extinction is to create a self-sustained colony off the Earth\u2014either on a massive spacecraft that could sustain multiple generations, or on another planet. That way, if we do get wiped off the face of the Earth, we will have a shot at repopulating it once the smoke clears.  If we face massive radiation from the supernova or gamma-ray burst of an exploding star, things won&amp;#039;t be quite so easy. It is possible that subterranean civilizations could save us, but we really need to colonize other star systems if we are going to avoid extinction with any certainty.  Let&amp;#039;s hope we can break ground on that Mars colony pretty soon, because we need all the time we can get to prepare for the inevitable species-threatening catastrophe.  "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/space/news/a22199/how-to-survive-a-mass-extinction/>