Nuclear Autopsy: Dissecting the latest tests on the Korean peninsula

This month in “humanity’s march towards total annihilation”, North Korea claimed to have detonated a hydrogen bomb and the international community cried foul (and bullshit). North Korea has the range to target many nations – including the United States – if it developed small enough warheads. Such a situation could lead to North Korea passing the U.S. for the “most people killed by nuclear weapons” award. In fact, the U.S. almost left the competition in the radioactive dust when it nearly decimated Goldsboro, North Carolina! These weapons are certainly frightening, but the design of a thermonuclear bomb is actually pretty inventive. I’m going to guide you through the basics of hydrogen bombs, and what evidence leads us to believe that North Korea does not actually have thermonuclear capabilities.

 Let’s start with your run-of-the-mill atomic bomb. They are powered by fission reactions, where atoms are split into atoms with smaller nuclei. You start with a small mass of a radioactive isotope, usually uranium or plutonium, that is unable to sustain fission chain reactions. You can then either shoot a smaller pellet of that radioactive isotope at the mass or compress it with 360 degrees of explosions. Either way, you create a mass capable of sustaining fission reactions and you end up with mushroom clouds. These reactions release kilotons (equivalent to thousands of tons of TNT) of explosive energy.

Why bother giving you that fission bomb refresher? Because in order to provide enough heat and energy for a hydrogen bomb, you need to detonate an atomic bomb first! This is why hydrogen bombs are commonly referred to as thermonuclear bombs – they require immense heat. Below is a generalized diagram of this weapon. The “primary” or first reaction is the fission bomb, which creates subatomic shrapnel and heat. In the “secondary” reaction, the heat and subatomic shrapnel causes fission of the fusion fuel, which releases hydrogen atoms. The immense heat and pressure causes these hydrogen atoms to fuse, meaning that their atomic nuclei join to create an entirely new helium atom. When the hydrogen atoms fuse and form helium, they release energy that catalyzes more rounds of fission and fusion. But don’t blink! All of these necessary chain reactions happen within milliseconds before the bomb explodes.

You might recognize the fusion of hydrogen as that thing the sun does. Therefore, using the transitive property of terrifying physics, you can imagine what it would be like creating a tiny sun right here on earth. While those puny atom bombs can be measured in kilotons, hydrogen bombs actually release megatons (equivalent to millions of tons of TNT) of energy. What does it mean to have weapons thousands of times more powerful than atomic bombs? Check out this comparison from CNN of atom bombs (little boy, fat man, and ivy king) to hydrogen bombs (B53, Castle Bravo, and Tzar Bomba).

In other words, Tzar Bomba is the colon blow to little boy’s fart in the wind. While I’m certainly concerned that countries have these weapons, the immense scale of their power should give you a clue as to why the world feels North Korea is lying about their claims of testing a hydrogen bomb. Here’s a map of nuclear tests performed by North Korea and the corresponding earthquakes each one caused.

Given that true hydrogen bombs are thousands of times more powerful than atomic bombs, don’t you think one might cause a greater earthquake than the last atomic bomb North Korea tested in 2013? Experts certainly think so, which is why they concluded the latest test was just another atomic bomb.

While a lot of creative science goes into making hydrogen bombs, I’m sure many of you like myself are perplexed by North Korea’s intentions. Why would they lie about detonating a hydrogen bomb in the first place? My brother actually visited North Korea in 2013, and I figured his insider information could give a fresh perspective. When asked about North Korea’s motives, he replied:

They saw what happened in Japan. The Korean peninsula has been invaded by multiple empires, and the USA is building bases and positioning ships closer and closer, and showing off its might with military practices. The leaders are scared. When that happens, the people are scared. And much like NRA members in the USA, they feel safer with something dangerous around…for protection, of course!

Maybe the second amendment can be applied to national defense, but the right to bear nuclear arms is a discussion best left for political scientists. However, I do think it’s important to be mindful of the risks we take in the pursuit of such ideals. Nuclear physics is as powerful as it is enthralling, and I hope humanity will continue to tap into its potential rather than its destructive force. Just remember that when it comes to identifying nuclear explosions, trust the earthquakes and not the rhetoric.

Austen (President)
austen_avatarAusten is a 5th year graduate student and president of Science ACEs. His dream is to go fishing every day once he’s finished with this bacterial pathogenesis thing. You can follow him on twitter @austenleet.
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