The Doomsday Clock now stands at 89 seconds to midnight, the closest to catastrophe in its nearly eight-decade history. Here's a look at how — and why — it's moved.

(Saul Loeb/AFP via Getty Images ... The Bulletin has reset the clock 26 times since 1947, when it debuted at 7 minutes to midnight.

In the past few years, to address rapid global changes, the group has changed from counting down the minutes until midnight to counting down the seconds. The group said the clock could be turned ...

The Doomsday Clock has moved one second closer to midnight, the metaphorical point ... Between 1988 and 1991, the clock was moved back by 11 minutes with the fall of the Soviet Union, the end ...