Some of the comments here remind me of the old Far Side cartoon with a bunch of generals around a war table.

So, the Bush Administration has intelligence indicating that a small dictatorship has weapons of mass destruction?

Something that has kept me up all night worrying on more than one occassion is the realization that, in some respects, building a nuclear bomb is not really all that hard. It takes a lot of effort and investment, but it's not really rocket science. Not anymore.

Think of it this way: the two A-bombs that killed almost 200,000 people in Japan and forced a sudden end to World War II were built with the technology of the early 1940's.

Do you know what it was they called a "computer" at Los Alamos? It was a guy sitting at a desk with a table of logarithms and a mechanical adding machine. They'd have a whole big room full of these guys to calculate numerical solutions to differential equations.

It wasn't until after World War II that the first electronic computers were built. From the very start these were brought to bear on the problem of designing more powerful weapons, but even these were orders of magnitude slower, and had orders of magnitudes less memory than today's desktop computers.

You want to design a nuke? Get someone with a PhD in physics and give him a Linux box with Mathematica and MATLAB. You'll have your design in no time.

Today's modern nuclear weapons factories enrich uranium through diffusion of a gaseous uranium compound. It's a very difficult, tricky process, and has to be done on an enormous scale to produce significant quantities. But that's not how they did it back during the Los Alamos days. They used large mass spectrometers, devices they called calutrons.

They're hard to get working right too, but in principle they are very simple - you send a beam of electrically charged uranium atoms through a magnetic field, created by a large electromagnet. The charged particles travel a curved path, bent by the magnetic field, with the more massive isotopes traveling a somewhat less curved trajectory. At the end of the path you collect the material on a metal plate. One side of the blob produced will be somewhat enriched. Scrape it off and run it through again.

Fissile uranium occurs plentifully in nature. You just have to dig it up out of the ground. It's not concentrated enough to explode, but all you need to enrich it to bomb grade is a large industrial plant and lots of electricity.

The industrial facilities and electic capacity of the 1940's United States are within reach of many third world countries of the early 21st century.

Scientific American published an article a while back about what the UN inspectors found in Iraq after the first war. Underground facilities full of calutrons, powered by underground cables that were laid over a hundred miles from the power plants that fed them - see, so know one would suspect.

Manhattan project scientists filed a number of top-secret patents that described ways to make the calutrons work better. But with the invention of gas diffusion, these patents were declassified because the technique was thought to be obsolete. Copies of these now-publicly-available patents were also found in Iraq.

Fissile plutonium does not occur in nature. You have to make it in a reactor, and it is produced only in tiny quantities so it takes a long time. The bombs are hard to make, with explosive lenses and a delicately balanced initiator that starts off the reaction.

But to make a uranium bomb, you just shoot a chunk of uranium out a cannon into another chunk of uranium so the two of them form a critical mass. Simple as pie.

These kinds of bombs are often referred to in the press as "crude" and "primitive" compared to the modern, more compact and much more powerful weaponry possessed by Russia and the US. But it was two such crude and primitive bombs that rained Hellfire over Hiroshima and Nagasaki.

Now for the reading I promised:

• The Making of the Atomic Bomb by Richard Rhodes
• Dark Sun: the Making of the Hydrogen Bomb, also by Richard Rhodes

I haven't read the hydrogen bomb book yet, but I looked through all the pictures while browsing in a bookstore. Especially disturbing are two pictures of the New York City skyline. On one is superimposed the mushroom cloud of a Hiroshima sized A-bomb, of such a size it could destroy the center of the city. On the other is placed the blast of a hydrogen bomb, so much bigger that it would vaporize New York in its entirety.

It really makes you stop to think: the bombs dropped on Japan were fifteen kiloton devices, equivalent to the explosive power of fifteen thousand tons of TNT. But hydrogen bombs are measured in MEGATONS. The first H-bomb test in the Pacific blew an island clean off the map and almost killed the observers who thought they were at a safe distance. I understand the most powerful bomb ever, tested by the Soviets, had a yield of I think 56 megatons.

There's a little joke I used to tell people, back in 1994, when the North Koreans were up to no good. I wasn't doing so well mentally, and was deeply worried, not just about the Koreans, but about every country that might have reason to want to become a nuclear power. I used to laugh in a manic sort of way when I would tell people. I felt it was my personal responsibility to warn the public so we wouldn't all get blown up.

Q: What did they call the first hydrogen bomb?

A: Mike.

-- Mike

-- "You're not as big an asshat as everyone seems to think." - Kurosawa Nagaya.

Both are complete BS, but serve effectively to whip us into a panic - dare I say terrify us?

Scared people are herded with ease. Serious discussion about the evidence for obviously far-fetched theories (WMDs? ICBM attacks?) only serve to reinforce that fear, since the threats appear plausible.

Baaa! Baaa! nucular tests! Baaa! Baaa!

After reading your article, I have decided to conduct nuclear tests in my backyard, for the sole purpose of telling the CIA to mind their own fucking business when they come knocking at my door asking what that was.

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Life is a tragedy to those who feel, and a comedy to those who think

I only hope that Willy Wonka and his cybrog Oompa-Loompas can prevail against this threat.

If it was a nuke, expect the Pacific Rim to go to hell in a handbasket (in terms of diplomacy and politics) in a hurry.

If North Korea has nukes, then Japan will quickly realize that the best option they have is a reliable deterrent. So Japan will develop its own nuclear weapons. They already have ICBMs (if a rocket can put a satellite in orbit, it can send a warhead on a sub-orbital flight).

Japan is not popular amongst its neighbors. Long memories over there, and things that are difficult to forget. A nuclear armed Japan means a nuclear armed Taiwan, and South Korea also (even more than North Korea having nukes). The PRC already has nukes and ICBMs.

I think the purpose of that was to calibrate the yield of the a-bomb. It was, if I recall correctly, fifteen kilotons (the explosive energy of fifteen thousand tons of TNT).

What better way to measure a-bomb yield than by comparing it to the actual power of a few kilotons of explosive. Sit some ways away with a seismograph and compare the needle wiggles.

Also, more recently, the US has used large quantities of explosives to simulate the blast from nuclear weapons, without having to violate the atmospheric test ban treaty. For example I read an article in which they tested the survivability of some mobile ICBM launchers by setting of an enormous hemispherical pile of ammonium nitrate right next to a prototype launcher.

If I'm right, then expect to see an actual nuke test soon.

-- "You're not as big an asshat as everyone seems to think." - Kurosawa Nagaya.