Sunday, February 17, 2013

Meteor Impact and Asteroid Flyby on the Same Day!

"According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point."
NBC News:
A meteor flared through the skies over Russia's Chelyabinsk region early Friday, triggering an atomic bomb-sized shock wave that injured more than a thousand people, blew out windows and caused some Russians to fear the end of the world.

NASA said it was the largest reported fireball since the Tunguska event in 1908 — an asteroid explosion that flattened millions of trees over 820 square miles of remote Siberian forest.

Friday's event was witnessed by throngs of Russians in Chelyabinsk, a city of 1.1 million in western Siberia. Multiple amateur videos posted online showed the meteor’s flaring arc stretching hundreds of miles across the sky. Other videos from the scene captured the sound of a loud boom, followed by a cacophony of car alarms. One video showed the hurried evacuation of an office building in Chelyabinsk.

“There was panic. People had no idea what was happening. Everyone was going around to people’s houses to check if they were OK,” Chelyabinsk resident Sergey Hametov told The Associated Press. “We saw a big burst of light then went outside to see what it was and we heard a really loud thundering sound.”

The impact involved a 50-foot-wide (15-meter-wide), 7,000-ton asteroid that zoomed in from space at a velocity of 40,000 mph (18 kilometers per second), NASA officials said. They said the shock of atmospheric entry blasted the rock apart at a height of 12 to 15 miles (20 to 25 kilometers), releasing the energy equivalent of 300 to 500 kilotons of TNT. That's more than 10 times the energy released by the atom bombs that exploded over Japan at the end of World War II. In fact, NASA said its estimates were based on readings from infrasound sensors that were set up by the Comprehensive Test Ban Treaty Organization to detect nuclear blasts.

No fatalities were reported, but Russia's Interior Ministry said about 1,100 people sought medical care after the shock wave. About 50 were hospitalized. Most of the injured were cut by glass from windows that were shattered by the blast's shock wave. More than 200 children at Chelyabinsk schools were said to be among the injured.

City officials told AP that 3,000 buildings in the Chelyabinsk region were damaged, including a zinc factory warehouse that lost its roof and part of a wall because of the shock wave's battering. Russia's Itar-Tass news agency said as many as 10,000 police were mobilized to aid in the recovery and remove debris.

There were no significant disturbances to public utilities or communications, Vladimir Stepanov of the Emergency Situation Ministry told Itar-Tass. "No serious consequences have been so far recorded," Stepanov said. "There has been no disruption in the rail and air transport work."

A search was conducted to find any fragments that survived when the space rock blew itself apart. A photo provided by the Chelyabinsk regional police department showed a 20-foot-wide (6-meter-wide) hole in the ice covering a lake near the town of Chebakul where some of the fragments reportedly fell.

The fireball hit just hours before a 150-foot-wide asteroid, known as 2012 DA14, came within 17,200 miles of Earth during an unusually close but harmless flyby. NASA officials said there was no connection between the two events. "It's simply a coincidence," said Paul Chodas, an asteroid researcher at NASA's Jet Propulsion Laboratory.

The asteroid has safely passed Earth, reaching its nearest point to the planet, and is now traveling away from us. According to Bill Nye, if the Earth had been 15.5 minutes further along in its orbit or if the asteroid had been 15.5 minutes closer, than it would probably have destroyed a city.

Using NASA's WISE infrared satellite, astronomers estimate there are about 5,000 known meteors that can impact the Earth with sizes of about 100 feet or larger -- that is, larger than the Chelyabinsk meteor. Smaller ones are fainter and thus harder to find.

More information:
» Asteroid 2012 DA14

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