Regardless of what your watch tells you, it’s 100 seconds to midnight. That’s the interval on the symbolic Doomsday Clock between the present moment and “planetary catastrophe.” The alternative rock band R.E.M. put it another way: “It's the End of the World as We Know It.”

In 1947, a group of scientists who had worked on the first nuclear weapons dreamed up the Doomsday Clock as a metaphor warning just how close humanity was to destroying itself. The iconic clock has been the symbol of the Bulletin of the Atomic Scientists ever since, and on its 75th anniversary the group’s experts say we’re closer than ever to that dreadful wakeup call. 

The clock