Carl Sagan (November 9, 1934 - December 20 1996) was an American Astronomer, Astrophysicist, author and promoter of science and reason. He was Director of the Laboratory of Planetary Studies at Cornell and a leader of our space program from the very beginning. He was also one of the most outstanding (unofficial) philosophers of our time. If our world was led by men like him, we'd have an impressive society and a bright future indeed.
Happy Carl Sagan Day. Go watch The Cosmos, or read Contact, or listen to/read some of Sagan's lectures today while you work. It's a shame such a brilliant man was taken from us too soon.