dr. caleb scharf it's wonderful here to have you. i found your book fascinating and a terrific read and i'm thrilled to be here. the great thing is i get to about -- get to ask you about some big questions that most people would not dare to answer and that's the real fundamental thought. so your book is called "the copernicus complex." maybe you could tell us a little bit about what that is. >> guest: absolutely. the copernicus complex is really a phrase that's trying to capture one of the aspects of what i think is perhaps the biggest questions can ask and sometimes we ask it nonscientific way. the book is really about the scientific question of whether or not we are alone in the universe. the copernicus complex refers to way we feel about ourselves. on the one hand, from copernicus we wrote that we are not central, we are not special in any way and that idea has propagated through the centuries and is really driven a lot of modern science. it is really the core of modern science and idea that has become known as cosmic mediocrity.