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The Debris From a London-Sized Asteroid Strike Would Block Out the Sun

It's been almost a year since a meteorite unexpectedly blew up over the city of Chelyabinsk, Russia. The explosion — which scientists say was a blinding 30 times brighter than the sun — sent off a shock wave that defaced 7,000 buildings and injured more than 1,400 people.
The amount of damage was undoubtably huge. But the actual rock? Not so much. At 18 meters around, it was roughly half as wide as Rio de Janeiro's Christ the Redeemer statue — big, but surprisingly small for an object that caused $33 million in repairs in a matter of minutes.
See also: The Hunt for Killer Asteroids
This got us thinking: What happens when smaller (and bigger) objects fly into our atmosphere? We used Purdue University's "Impact: Earth!" simulator to find our answers. Our own Bob Al-Greene illustrated the results, as seen in the gallery above.
Some highlights: Rocks the size of basketballs enter our planet about once a month; most burn apart in the atmosphere before they reach the surface. Objects as long as standard school buses (roughly 12 meters around) only sneak into the Earth every 20 years or so — but, as seen in Chelyabinsk, the damage can be much greater.
All results assume the object is traveling at a 45-degree angle, with a density level of 3000 kg/m^3 and a velocity of 11 km/s. Everything is assumed to be seen from 100 kilometers away from the direct impact zone.
Click "Show As List" on the bottom-left of the gallery to view larger images. And check out our Google Hangout with asteroid experts to learn more about what's being done to fend off space rocks, from basketball-sized to London-sized.

BONUS: NASA's Plan to Save the Earth From Killer Asteroids

Topics: gallery, space, Travel & Leisure, U.S., US & World, Videos, Work & Play, World
Image: NASA

সোর্স: http://mashable.com

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