INCOMING!: метеорита в Челябинске, Russian Meteor - February 2013 Options

[volcanopele]

Looks like a small meteoroid decided to spoil 2012 DA14's big day by exploding over Russia...

http://zyalt.livejournal.com/722930.html?nojs=1

[Mongo]

Russian meteor largest in a century -- Nature

A meteor that exploded over Russia this morning was the largest recorded object to strike the Earth in more than a century, scientists say. Infrasound data collected by a network designed to watch for nuclear weapons testing suggests that today's blast released hundreds of kilotonnes of energy. That would make it far more powerful than the nuclear weapon tested by North Korea just days ago and the largest rock crashing onto the planet since a meteor broke up over Siberia's Tunguska river in 1908.

"It was a very, very powerful event," says Margaret Campbell-Brown, an astronomer at the University of Western Ontario in London, Canada, who has studied data from two infrasound stations near the impact site. Her calculations show that the meteoroid was approximately 15 metres across when it entered the atmosphere, and put its mass at around 7,000 metric tonnes. "That would make it the biggest object recorded to hit the Earth since Tunguska," she says.

Although there are reports of fragments of the meteor, or meteorites, striking the ground, Klinkrad says that he believes the vast majority of damage in the region was caused by shockwaves of the explosion, as the rock broke up in the upper atmosphere. Campbell-Brown says that the infrasound data shows a very shallow angle of approach — a feature that funnelled much of the energy from the blast to the city below. Still, she adds, "It's lucky that there wasn't more damage."

The impact effects website I have been using says that the energy released during the major explosion, with these numbers, would be around 320 KT. Allowing for shock wave interference effects and shoddy Russian window construction, I suppose the observed damage is possible. Needless to say, it's still one heck of an explosion.

edit -- Since I wrote the above, I learned that:

The meteor entered the Earth's atmosphere at a hypersonic speed of at least 54,000 km/h and shattered about 30 to 50 kilometres above the ground, the Russian Academy of Sciences said in a statement.

It released the energy of 300 to 500 kilotons above the Chelyabinsk region, the academy said.