The test likely pushed Pyongyang's scientists and engineers closer to their goal of building a warhead small enough to place on a missile that can reach the U.S. mainland. But South Korea's spy agency ...

SEOUL, South Korea (AP) — North Korea says it has conducted a hydrogen bomb test. The surprise announcement that complicates already difficult efforts to curb the country's push for a working nuclear ...

SEOUL, South Korea (AP) – North Korea says it has conducted a hydrogen bomb test. The surprise announcement that complicates already difficult efforts to curb the country’s push for a working nuclear ...

SEOUL, South Korea -- North Korea says it has conducted a hydrogen bomb test. The surprise announcement that complicates already difficult efforts to curb the country's push for a working nuclear ...

SEOUL, South Korea — North Korea’s declaration that it had tested a hydrogen bomb for the first time was greeted with widespread condemnation — but also skepticism — as world powers vowed Wednesday to ...

SEOUL, South Korea — North Korea says it has conducted a hydrogen bomb test. The surprise announcement that complicates already difficult efforts to curb the country's push for a working nuclear ...

A successful H-bomb test would be a big advance in North Korea's nuclear weapons program. Fusion is the main principle behind the hydrogen bomb, which can be hundreds of times more powerful than ...

TOKYO — The announcement Wednesday from North Korea that it had carried out a nuclear test brought to the front lines of global attention a phrase not often heard since the Cold War — "the H-bomb." As ...

A Handley Page Hastings (TG 582) flying over London, Christmas Island (now Kiritimati), Line Islands, in August 1956, at the time of the British H-bomb test. The United Kingdom’s secretary of state ...

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) Matthew Bunn, Harvard Kennedy School (THE CONVERSATION) Richard Garwin, who died on ...