We Can Survive Killer Asteroids — But It Won’t Be Easy

The chances that your tombstone will read “Killed by Asteroid” are about the same as they’d be for “Killed in Airplane Crash.”


Neil deGrasse Tyson

Solar System debris rains down on Earth in vast quantities — more than a hundred tons of it a day. Most of it vaporizes in our atmosphere, leaving stunning trails of light we call shooting stars. More hazardous are the billions, likely trillions, of leftover rocks — comets and asteroids — that wander interplanetary space in search of targets.

Most asteroids are made of rock. The rest are metal, mostly iron. Some are rubble piles — gravitationally bound collections of bits and pieces. Most live between the orbits of Mars and Jupiter and will never come near Earth.

But some do. Some will. More than a thousand known asteroids are classed as “potentially hazardous,” based on size and trajectory. Currently, it looks doable to develop an early-warning and defense system that could protect the human species from impactors larger than a kilometer wide. Smaller ones, which reflect much less light and are therefore much harder to detect at great distances, carry enough energy to incinerate entire nations, but they don’t put the human species at risk of extinction.

Every few decades, on average, house-sized impactors collide with Earth. Typically they explode in the atmosphere, leaving no trace of a crater. Once in about a hundred million years, though, Earth is visited by an impactor capable of annihilating all life-forms bigger than a carry-on suitcase.

http://www.wired.com/wiredscience/2012/04/opinion-tyson-killer-asteroids/?

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