North Korea warned this week that it might test a hydrogen bomb in the Pacific Ocean, after saying the country had already successfully detonated one. A hydrogen bomb has never be ...

The 80th anniversary of the atomic bombing of Hiroshima and Nagasaki is this week. It was the only time nuclear warheads were used during war. Here’s a look at the history and current U.S. stockpile.

THE FIRST NUCLEAR reactor on earth went critical 2 billion years ago in western Africa when groundwater seeped into a rich vein of uranium ore. It controlled itself elegantly, its water moderator ...