He roamed the halls of NASA as a little kid. Now he's one of the world's foremost astrophysicists. Harvard astrophysicist Jonathan McDowell joins the show. We talk Black Holes, Time Travel, Dark Energy and Space Exploration. Then, John Shull brings us back down to earth with his deja vu theory. And we discuss the Top 5 fictional dogs.Jonathan McDowell: Learn more about your ad choices. Visit megaphone.fm/adchoices