From December 23rd to January 1st, we will be showcasing our most notable conversations of the year. Today's show: Inside our individual worlds we’re asking, “when will this all end?” The answer, at least when it comes to the actual universe, is give or take a couple billion years. North Carolina State University theoretical astrophysicist Katie Mack joins host Krys Boyd to talk about the math, science and mystery that allows space to predict our demise back here on Earth. Her book is “The End of Everything (Astrophysically Speaking).”