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Saturday, February 16, 2013

Update on Chelyabinsk, Russia Meteor

The meteor that crashed near Chelyabinsk, Russia on Feb. 15, 2013 was about 50 now 55 feet in diameter when it entered the earth's atmosphere at an angle of 20 degrees to the horizon, moving at a speed of some 40,000 MPH and is estimated to have weighed 10,000 tons and delivered an explosive force of 300 now 500 kilotons of TNT, about 15x 25x the explosive force of the atomic bomb dropped on Nagasaki, ending WWII. It was about 1/3rd the size of mini-asteroid 2012 DA14 that coincidentally swept by the earth that same day at a distance of 17,200 miles. Although the chances of both coming so close to earth on the same day were minuscule, according to NASA the two were unrelated since the Chelyabinsk Meteor came from a completely different direction. Over 1,100 people were injured, mostly by breaking glass from the exploding fireball.

Orbits of asteroid 2012 DA14 and the Chelyabinsk Meteor. The Chelyabinsk Meteor was estimated at 15 feet in diameter (contrary to the caption here), weighing 10,000 tons, entering the earth's atmosphere from the direction of the sun in daylight. NASA has traced it's orbit back originating in the asteroid belt between Mars and Jupiter. Asteroid 2012 DA 14 was some 3x larger in size, comparable to the size of the Space Shuttle, and passed close by earth at a distance of 17,200 miles, between the ring of orbiting geosynchronous satellites and the surface of our planet.

It is not uncommon for stony meteors to explode in flight. The Chelyabinsk Meteor exploded into fragments at a height of about 12-15 miles, according to NASA. You can see and hear the explosion in many of the videos that were posted online.

Chelyabinsk is a large industrial city about 920 miles west of Moscow in the Ural Mountains. It is the location of one of only two plutonium processing plants in Russia whose output is used in making nuclear bombs. Had this meteorite struck during the cold war it could have mistakenly  triggered nuclear armageddon.

Comparison of different size meteors and the damage they can inflict. The Tunguska Event, also in Russia in 1908, destroyed 800 square miles of Siberian Forest. Had it fallen in a populated area it would have been an unparalleled disaster. The 10 kilometer asteroid that fell 65 million years ago in what is now Mexico was a planet killer, wiping out the dinosaurs and some 90% of the species then living.

As of this writing the only sign of the meteoroid on the ground is this 30 foot wide hole a fragment of it made in the ice covering Lake Chebarkul near the town of Chelyabinsk. The temperatures here get below 0 degrees Fahrenheit at night, so the ice is probably over 12 inches thick. So far Russian divers have found nothing in the lake, an unfortunate place for a large chunk to have landed since it will quickly become contaminated with debris from earth.

A thirty-foot hole in Lake Chebarkul marks the landing place of a fragment of the Chelyabinsk Meteorite.

Here is a terminological clarification:

Meteor: A streaking light in the sky, caused by a rock from space burning up as it enters the earth's atmosphere. Also called a "shooting star".
Meteoroid: The rock that burns up in the earth's atmosphere.
Meteorite: What a meteoroid is called when it strikes the earth, leaving pieces of itself behind.
Bolide: A meteor so bright that it can be seen in the daytime.
Fireball: Common name for a bolide.

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