The Doomsday Clock, the Bulletin of the Atomic Scientists’ ticking nudge to the world’s conscience, moved two minutes closer to nuclear midnight yesterday, the closest to doomsday it has been since the Cold War. North Korea’s nuclear bomb test, Iran’s nuclear plans, and atomic energy projects posed as an answer to climate change prompted the scientific journal to move the hands of the clock on its cover to 11:55. Midnight represents doomsday on the clock, for six decades a symbolic indicator of the threat posed by nuclear proliferation.