For sake of argument, let's just say aliens do exist... then, that begs the question, where are they? Why can you never find an alien when you need one? Mike gets explanations and theories from Jim Al-Khalili, author and professor of theoretical physics at the University of Surrey, on both sides of the argument of whether or not aliens exist and if they do, where they might be hiding. Got questions? Email Mike at ivegotquestions@audacy.com