Monday, September 13, 2004

What didn't happen in North Korea
from the mind of  Duke.

There has been a lot of speculation on just what happened in North Korea. Some of it is informed; some of it is not. So I'm going to do something a little different and make of list of things that I don't think happened.

1. It really was a nuke and everyone is covering it up!

In order for this explanation to work, you'd need the complicity of the following groups: every nation on the planet, every seismologist who knew what to look for, and the operators of all the satellites that happened to be overhead when the electromagnetic pulse hit.

But it was a mushroom cloud, and everyone knows that mushroom clouds are the result of nuclear weapons!

Nope. You don't need a nuke to make these suckers. I remember as a kid on the fourth of July being able to reliably create little mushroom clouds with black cat firecrackers and some dirt (both being in ample supply). Good times. Scientific American has a good summary of the physics involved:
"A mushroom cloud forms when an explosion creates a very hot bubble of gas... The hot air is buoyant, so it quickly rises and expands. The rising cloud creates a powerful updraft which picks up dust, forming the stem of the mushroom cloud. The central part of fireball is hottest, creating a rolling motion as it interacts with the outer portions.
Open question: just what do the seismologists have to say? I recon we'll be hearing from them soon.

2. It was a test of a weapon like our BLU-82 (Daisy Cutter) or GBU-43 (MOAB) .

This seems unlikelygiven that the explosion happened at night. You simply don't test weapons at night. The only reason you might do so is to keep something secret, which is clearly impossible with an even of this magnitude.

A better argument against the MOAB theory is the North Korea aircraft inventory. I don't think there is anything here that is really capable of delivering such a weapon.

3. They really were building a dam... or something.

I don't know if anyone really believes this, but what the hell. The thing is, big explosions pretty much suck for the purposes of excavation. Yes, some coal mining is done with explosives, but these are long strings of smaller detonations, rather than one big one.

Back in the day when I wrote physics simulations for a living, I once attempted to write an asteroid impact simulator. There were all sorts of variables: composition of the asteroid, density of the rock at the impact area, velocity, angle of impact, and so on. But one interesting thing quickly became apparent: past a certain (poorly defined) energy threshold, the resulting craters all started looking alike. Most of the material thrown up by the explosions quickly fell right back down into the hole and refilled it. Big craters were almost invariably quite flat with a shallow rim. This was rather disappointing to someone like me who was hoping to render some cool pictures of big, deep craters.

Perhaps the North Koreans really will flood the area and say "See? It really was a dam!" I'm sure the French will believe it.

So what do I think happened? I don't think we can rule out an accident yet. Communist countries have a lousy record of keeping things from blowing up by accident. I'm guessing that the North Korean version of OSHA is a little underfunded.

Another possibility is that this was a test meant to examine blast pressures like those produced by a nuclear detonation. Our military has conducted similar tests. The test ban treaty forbids using actual nuclear weapons, so we just piled up enough conventional explosives and moved the instruments closer to ground zero to simulate a farther distance from a larger nuke (the inverse-square law is your friend here). I believe that yields of several kilotons have been achieved in such tests. Of course, this still runs afoul of my "it happened at night" objection, but it's at least a little more believable.

I'm sure we'll have more information to work with in the next few days.

1 Comments:

Blogger BillyBudd said...

Thanks for blowing up my MOAB theory! Also thanks for the education. You can bet the little bastard is up to something though.

10:13 PM  

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