North Korea tested a nuclear device today that Kim Jong-un claims was a miniaturized hydrogen bomb, capable of being fitted to an ICBM. But some experts doubt that claim, which raises questions why Kim would lie about the test. What makes some experts skeptical is that the first measurements of the blast yield suggest they detonated either a high yield fission weapon or a very small, low yield fusion device. At an estimated 100 kilotons, the test was about 10 times more powerful than any previous nuclear test by North Korea. But successfully testing a hydrogen device carries with it engineering challenges that many believe is beyond the capability of the North to solve. A thermonuclear device is triggered by a fission explosion, much like the bomb used to destroy Hiroshima. The heat from the detonation fuses hydrogen atoms which release enormous amount of energy. But miniaturizing such a device requires the capability of manufacturing a warhead  with...(Read Full Post)