Feb 152013

According to JPL:

The meteor entered the atmosphere at about 40,000 mph (18 kilometers per second). … The size of the object before hitting the atmosphere was about 49 feet (15 meters) and had a mass of about 7,000 tons.

Plugging in the mass and velocity, we get a kinetic energy of 1134000000000000 joules. This works out to the equivalent of 271 kilotons.

There are a number of “bomb effects calculators” online that will show you what sort of damage you can expect from what sort of yield. Here’s one, putting a 271 kiloton blast in default New York City (apparently the Gold Standard in places to blow up):

newk york

Note that it puts an overpressure of 0.25 psi – what will blow out most windows – at a distance of 12 miles, much greater than the 50 km or so distances for such damage in Russia. Of course the Russian blast was at much greater altitude… that would certainly play into the effects. Exactly *how,* I’m a little unclear on.

The old-school Nuclear Bomb Effects Computer gives roughly equivalent results… for a 271 kton air blast, range to .25 psi is about 14 miles.

It should, I hope, concern everyone that a chunk of space debris massing 7,000 tons – more than a Los Angeles class attack sub – and about 15 meters across apparently managed to completely evade detection until it hit the atmosphere.

 Posted by at 4:00 pm
  • Nick P.

    It does concern me.

    It also concerns me if the *BIGGER* asteroid that flew by today went through the so called ‘keyhole’ or not potentially leading to a future impact, haven’t heard yet.

    It concerns me even further that it seems very unlikely for an asteroid to so spectacularly enter our atmosphere on the same day that the aforementioned rock happens to be sailing by, thus conjuring notions that perhaps this is a cluster of rocks in a common orbit with more possible hits on the way.


    If someday something big enough hits us and blocks out the sun for a spell due to dust-and-such I propose eating the politicians first when we inevitably descend to cannibalism just before the final crash into anarchy and collapse.

    • hemorrhoid

      So they say their paths were perpendicular; what if the asteroid and a cloud of smaller rocks were, as you say, in a common orbit, say tracing out a double helix. In that case, the path of the asteroid and the rocks WOULD be perpendicular when they struck the earth.

      • Anonymous

        > tracing out a double helix

        Such orbits do not exist.

    • Anonymous

      > perhaps this is a cluster of rocks in a common orbit

      Nope. Completely different orbits. Just a cosmic coincidence.

  • General Zhukov

    The nuke calculator assumes the “bomb” goes off at the optimum altitude to maximize destrution, something which is unlikely with a boloid, assuming, of course that it hasn’t been actively aimed by some intelligence. 🙂