The Science Behind North Korea's H-Bomb Claim

Did North Korea really join the H-bomb club? It will take weeks for the rest of the world to confirm the exact nature of Pyongyang's latest test. In the meantime, here's a look at the science involved in the process:

• Fission vs. fusion: The Atlantic explains the difference in terms of water balloons. North Korea has previously detonated atom bombs that use fission. "Like a dropped water balloon hitting a sidewalk, atomic bombs crack open the dense atomic nuclei of large, unwieldy elements like uranium and plutonium to release tremendous amounts of energy." A hydrogen bomb is akin to "filling up a water balloon until it bursts." Nuclear fission factors into only the initial detonation, which "[ignites] a secondary fusion stage by compressing lighter atoms of deuterium and tritium together until they explode."
• The concern: "A fission weapon typically yields around 10 kilotons, while a fusion weapon is measured in megatons (1,000 kilotons)," notes Daily Intel. To put it in perspective, we're talking about a potential weapon "hundreds of times more powerful" than what decimated Hiroshima and Nagasaki.

• Maybe just 'boosted': Instead of a full-fledged hydrogen bomb, this could have been an atom bomb "boosted" by a small amount of fusion. "Weapon designers can easily boost the destructive power of an atom bomb by putting at its core a small amount of tritium, a radioactive form of hydrogen," reports the New York Times.
• But even so: A boosted atom bomb would be in the 50-kiloton range, which would be catastrophic if used on a densely populated city such as Seoul, writes analyst Bruce Bennett at CNN. "About 250,000 people could be killed in such a strike, or about 2.5% of the population."
• Enough experience: Be skeptical, but remember that North Korea has had a nuclear program, resulting in three previous detonations, for 20 years now, writes Jeffrey Lewis at 38 North. "We should not expect that they will test the same fission device over and over again." Still, he thinks a "staged thermonuclear weapon" is likely too advanced for the North at this point, with the "boosted" theory more plausible.
• History.com looks back at America's first hydrogen bomb test in 1952.

(More North Korea stories.)