Friday, February 15, 2013

Playing Whack-a-Mole

The big news this morning was that we had spectacular round of Whack-a-Mole in Chelyabinsk, Russia.  As I said in that linked piece, from 2010,
Remember the arcade game?  Moles pop up in a field of holes and you club them down with a mallet?

Unfortunately, our planet is engaged in cosmic game of whack-a-mole.  How bad is it?  I've undertaken realistic scientific simulations using a common sledge hammer and a hamster and I have to say it's not pretty.  In fact, it's so "not pretty" that decorum prevents me from posting pictures of it.
It didn't take long for authorities to say they believe they found the impact point of a big surviving chunk, as it punched a pretty nice hole in the ice of Chebarkul Lake
Army units found three meteorite debris impact sites, two of which are in an area near Chebarkul Lake, west of Chelyabinsk. The third site was found some 80 kilometers further to the northwest, near the town of Zlatoust. One of the fragments that struck near Chebarkul left a crater six meters in diameter.
The meteor was estimated, according to Russia Today, to be 10 metric tons, and moving at 30km/sec or 67,000 MPH.   Turning that into the energy released, it's (1/2) mV^2 or 10,000 kg times (30,000 m/sec) times (30,000 m/sec) or 9,000,000,000,000 (9 trillion) joules of energy. The handy-dandy "convert to" website says that's the same as 2150 tons of TNT - a 2 kiloton bomb.  NASA says the meteor was "only about the size of a bus and weighed an estimated 7,000 tons, it exploded with the force of 20 atomic bombs". They don't provide enough numbers to test their calculations. 

There are some cool videos that give a good look at the fireball so you can see how bright it was, like this one.  and a longer video that shows a street scene so you can see how many windows and doors were blown out by the explosion.  A real shaky-cam with lots of excited commentary in Russian (I assume). 

Of course, this meteor was not related to the much publicized asteroid 2012 DA14 which passed by uneventfully as predicted. 

That's the thing about the Great Cosmic Whack-A-Mole game: not every piece that can cause some damage is known about.  Most of these unknown, untracked hunks, like this one, could knock over buildings or pretty thoroughly mess up a city.  It's a game.  You're in it.  No, you were not asked to join. It's part of the risks that come with life.  The next one could come in a second or not for 100 years.  It could land in the Pacific (most likely - it covers the most area of the globe), or it could land in your backyard.   


  1. Brit press (Telegraph) is reporting that, "according to NASA, the meteorite weighed about 10,000 tons and exploded with a force equivalent to 500 kilotons."

    1. That's a bit more precise than the NASA page I quoted. After all, what does "20 atomic bombs" mean? 20 small (20 kiloton) bombs or 20 big (1 megaton) bombs?

      I suspect that number is going to be revised for a while as they examine reports of damage.