the very first "cosmos" exactly 40 years ago, carl sagan and stevens odor and i celebrated the libraryf alexandria. the library of congress means so very much to me because of the democratic idea of the world's knowledge to all of us so it is my honor to be here. to talk about possible worlds, the book i have written and the television series i had the pleasure of producing, writing and directing with my collaborator. why "cosmos: possible worlds," why a third "cosmos" after 30 years? the first "cosmos" was an effort to give the broadest possible public, a global public its coordinates in space and time. it was carl sagan's dream, one that i completely share, that how we find our way in the cosmos, the great story of 40,000 generations of human beings who in one way or another added to our current understanding, the wonderful inspiring stories to a global audience so as many of us as possible could have a cosmic perspective for space and time and in that original series there was the cosmic calendar in which we compressed what was then thought to be something like 18 billion year of co