What is the Doomsday Clock? It's 2025 and scientists have reset the clock closer to midnight and global catastrophe. Here's what it all means.

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.

The science that guides the Doomsday Clock, which represents how close humanity is to global catastrophe, has been moved to 89 seconds to midnight, the closest it has ever been.