If ever there was "a riddle wrapped in a mystery inside an enigma" --Winston Churchill's inimitable phrase-- it is a black hole. In this spirited exchange from NOVA Online, one man struggles to explain these deeply weird outerspace entities while his interlocutor struggles just as hard to understand them. The first is astrophysicist Steven Ritz of NASA's Goddard Space Flight Center and the University of Maryland, and the second is Tom Lucas, producer of "Monster of the Milky Way." Will their conversation help you get a better fix on just what these mind-bendingly strange objects are? We hope so, but regardless we think you'll enjoy the ride.