Forget the Mayan Apocalypse: 5 ways the world might actually end

DRESDEN, GERMANY - NOVEMBER 08: A sky caiman vomits water on one of the last pages of the 12th-century Dresden Codex, also known as the "Codex Dresdensis", one of four historic Mayan manuscripts that still exist in the world and that together suggest modern civilization will come to an end on December 21, at the Saxon State Library on November 8, 2012 in Dresden, Germany. The documents enumerate the Mayan calendar, which will complete its 13th cycle on December 21, 2012 and many people across the globe are interpreting the calendar to mean impending global devastation and the birth of a new order are near. (Photo by Joern Haufe/Getty Images)

As you may know, December 21, is the last day in the Mayan calendar. Many people have interpreted that as a sign of the apocalypse, our last day on Earth.But even if the world doesn't end today, that doesn't mean we're off the hook.

As you may know, December 21, is the last day in the Mayan calendar. Many people have interpreted that as a sign of the apocalypse, our last day on Earth.

But even if the world doesn't end today, that doesn't mean we're off the hook. There are plenty of doomsday scenarios still left and our next guest makes it his life's work to think about them.

Stuart Armstrong, a research fellow at the Future of Humanity Institute at the University of Oxford, joins the show to explain the top five ways the world might actually end:

1) Synthetic biology
2) Nuclear war
3) Artificial intelligence
4) Pandemics and plagues
5) Nanotechnology