Today on Cool Science Radio, John and Lynn's guests are:(0:50) Sean Carroll, a theoretical physicist at the California Institute of Technology, host of the popular Mindscape podcast and a best selling author. Sean’s newest book is The Biggest Ideas in the Universe…Space, Time, and Motion.Then (25:36) Randell Munroe who is the The #1 New York Times bestselling author of What If? is back answering more of the weirdest questions you never thought to ask in his new book What if 2?