It's Carl Sagan's birthday! Time to party like the starstuff that we are.Robbie Gonzalez11/09/12 5:14pm18EditPromoteGo to permalinkHappy birthday, Carl Sagan! The legendary astronomer, astrophysicist, cosmologist and science educator would have been 78 today. To celebrate, we've rounded up a handful of our favorite Sagan posts and curated some stellar content from other websites that are honoring him today. Feel free to contribute in the comments!