The H-bomb: What is it? Who has it? Why it matter

North Korea announced Wednesday that it had successfully tested a hydrogen bomb.

If true, it now possesses something much more powerful than the weapons it has tested in the past.

The nuclear age is has entered its eighth decade, and while relatively few nations possess the power, the potential consequences of North Korea upping its nuclear game from a basic atomic bomb to a hydrogen bomb has caught the world's attention.