It has been maintained since 1947 by the members of the Science and Security Board of the Bulletin of the Atomic Scientists, who are in turn advised by the Governing Board and the Board of Sponsors, including 18 Nobel Laureates. The closer they set the Clock to midnight, the closer the scientists believe the world is to global disaster.
The Clock originally hung on a wall in the Bulletin’s office in the University of Chicago and represented an analogy for the threat of global nuclear war. An international group of researchers called the Chicago Atomic Scientists who had participated in the Manhattan Project came up with idea of an actual doomsday clock. After the atomic bombing of Hiroshima and Nagasaki, they started to publish a newsletter and then a bulletin. The Clock has been depicted on every cover of the Bulletin of the Atomic Scientists. Since 2007 the clock also now reflects climate change and new developments in the life sciences and technology that could inflict severe harm to humanity.
In 2009, the Bulletin stopped its print edition and was one of the first print publications in the US to become entirely digital. The clock has been adjusted 21 times since 1947, when the Clock was initially set to seven minutes to midnight. Today it stands at 3 minutes til midnight.