The Doomsday Clock is inching closer to midnight. What exactly does that mean?

You've probably heard that the Doomsday Clock is inching closer to midnight. We wanted to find out what exactly that means and if it's actually as terrifying as it sounds. Dr. Rachel Bronson, president and CEO of the Bulletin of the Atomic Scientists joins KYW Newsradio In Depth to break down what the Doomsday Clock means, who determines what time it is, and how to measure the existential threats facing humanity.