https://www.scientificamerican.com/article/north-korea-panics-the-world-but-h-bomb-test-changes-little/ >The following essay is reprinted with permission from The Conversation, an online publication covering the latest research. >North Korea has conducted its sixth nuclear device test, and based on what we know so far it looks like by far the biggest yet. Pyongyang’s own news agency, KCNA, described the test as a “perfect success”, and claimed the device was an advanced hydrogen bomb small enough to fit atop a long-range missile.