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Russian meteor not related to asteroid 2012 DA14, scientists say

February 15, 2013|By Monte Morin
  • A meteorite trail is seen above a residential apartment block in the Russian city of Chelyabinsk.
A meteorite trail is seen above a residential apartment block in the Russian… (Oleg Kargopolovoleg )

The meteor that blazed over a portion of Russia early Friday, blasting windows and triggering car alarms with a series of explosive booms, was not related to asteroid 2012 DA14 and had a very different trajectory, according to scientists at NASA.

As numerous videos of the event were viewed worldwide, experts said the meteor was likely about one-third the size of 2012 DA14, too small to track and therefore a surprise.

The largest noise heard on video of the event was likely the main mass of the meteor exploding 100,000 to 150,000 feet above the Earth's surface, and not a sonic boom, scientists said.

"The shock wave that broke all this glass and I think collapsed a tin roof in a building, that was from the explosion," said Paul Dimotakis, professor of aeronautics and applied physics at Caltech.

"Meteors come in as solid matter, but the heat from aerodynamic friction begins to melt everything," Dimotakis said. "As the temperature continues to rise, everything gets vaporized, from rocks to metals to everything."

It is this transition from liquid to gas that creates an explosive shock wave, because there is such a rapid and immense increase in volume.

The dynamic, Dimotakis said, is very similar to a nuclear explosion. "It's like inflating a balloon instantly. It creates a shock wave," Dimotakis said.

Subsequent explosive noises were likely sonic booms created by pieces of the meteor that broke off prior to the explosion, he said.

"Looking at the pictures of the trail, it looked like this thing was shedding stuff before it exploded," Dimotakis said. "That's not the trail of something that remains intact until the explosion."

Those meteorites that are recovered are the smaller portions that broke off, Dimotakis said. After breaking off from the main mass, they decelerated and did not vaporize before landing. "They fell to earth as rocks," he said.

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