The Doomsday Clock has been used to examine the world’s vulnerability to global catastrophe for nearly a century.

In the sense of the Doomsday clock, it means how close we are to catastrophe. U.S. figure skater Spencer Lane, 16, shared a photo from inside American Eagle Flight 5342 before it took off from Wichita,

You can stop a clock from ticking, but it's a lot harder to figure out how to stop humanity's relentless march toward self-annihilation.