The Bulletin of the Atomic Scientists is a nonprofit organization concerning science and global security issues resulting from accelerating technological advances that have negative consequences for humanity. The Bulletin publishes content at both a free-access website and a bi-monthly, nontechnical academic journal. The organization has been publishing continuously since 1945, when it was founded by Albert Einstein and former Manhattan Project scientists as the Bulletin of the Atomic Scientists of Chicago immediately following the atomic bombings of Hiroshima and Nagasaki. The organization is also the keeper of the symbolic Doomsday Clock, the time of which is announced each January.

The Doomsday Clock is a symbol that represents the likelihood of a human-made global catastrophe, in the opinion of the members of the Bulletin of the Atomic Scientists. Maintained since 1947, the clock is a metaphor, not a prediction, for threats to humanity from unchecked scientific and technological advances. That is, the time on the clock is not to be interpreted as actual time. A hypothetical global catastrophe is represented by midnight on the clock, with the Bulletin's opinion on how close the world is to one represented by a certain number of minutes or seconds to midnight, which is then assessed in January of each year. The main factors influencing the clock are nuclear warfare, climate change, and artificial intelligence. The Bulletin's Science and Security Board monitors new developments in the life sciences and technology that could inflict irrevocable harm to humanity.