It uses the analogy of the human race being at a time that is "minutes to midnight" where midnight represents destruction by nuclear war.
Since its introduction, the clock has appeared on the cover of each issue of the Bulletin of the Atomic Scientists.
The number of minutes before midnight, a measure of the degree of nuclear threat, is updated periodically. The clock is currently set to five minutes to midnight (the 1st time ever set to 5 minutes), having been advanced by two minutes on January 17, 2007.
The furthest the clock has been is 11:43, 17 minutes to midnight, in 1991 when the USA and Russian signed a nuclear arms reduction treaty. The closest the clock has been set to midnight was in 1953. The USA and USSR both tested nuclear arms within weeks of each other. The clock was set to 11:58, two minutes to midnight.
The clock was started at seven minutes to midnight during the Cold War in 1947, and has subsequently been advanced or rewound at intervals, depending on the state of the world and the prospects for nuclear war. Its setting is relatively arbitrary, set by the Board of Directors at the Bulletin of the Atomic Scientists in response to global affairs.
The setting of the clock has not always been fast enough to cope with the speed of global events, either; one of the closest periods to nuclear war, the Cuban Missile Crisis in 1962, reached its head and resolution in a number of weeks, and the clock either could not be changed or was not changed to reflect any of this at the time. Nevertheless, the changing of the clock usually does provoke attention.
The clock's hands have been moved 18 times in response to international events since its initial start at seven minutes to midnight in 1947.
Neil Steinberg at the Chicago Sun-Times declares the Doomsday clock to be one of the most successful PR endeavors a magazine has ever developed. By simply illustrating how near they believe the world is to global nuclear destruction a relatively obscure magazine has gained enormous political significance and newsworthy importance (http://www.suntimes.com/news/steinberg/217470,CST-NWS-stein19.article ).
When a scientist says it's five minutes to midnight it makes headline news.
That there is awe and respect given to the University of Chicago’s Doomesday Clock is not surprising. Alarmist tactics have always been able to generate respect and serious consideration as long as they have not come from Christians.
When a physicist, a scientist or Al Gore say that the world is in trouble and a state of decay people declare them to be insightfull, discerning and courageous. When a Christian believes that sin has damaged God’s creation and the only hope of rescue is Jesus Christ we’re denegrated as unreasonable, nonsensical wackos.
When a preacher says that Jesus is coming back soon it makes people mad.
Jesus had the same complaint concerning the people of his day.
They would look to the weather, the sun, the stars and moon and draw conclusions based upon what they saw. “And he said also to the people, When ye see a cloud rise out of the west, straightway ye say, There cometh a shower; and so it is. And when ye see the south wind blow, ye say, There will be heat; and it cometh to pass. Ye hypocrites, ye can discern the face of the sky and of the earth; but how is it that ye do not discern this time? Yea, and why even of yourselves judge ye not what is right?” ( Luke 12:54-57 ).
He declared them to be hypocrites because they could discern the face of the sky but they could not discern the signs of the times ( http://bible.cc/matthew/16-3.htm ).
Is there really a clock that is measuring the time remaining for the earth? Yes.
Is it located in the physics department of the University of Chicago? No.