Carl Sagan was an American astronomer and champion of skeptical inquiry and the scientific method. His PBS miniseries, Cosmos: A Personal Voyage, is still one of the most highly regarded science documentaries of all time. Sagan was an outspoken advocate for education and promoted the search for extra-terrestrial intelligence.
"The brain is like a muscle. When it is in use, we feel very good. Understanding is joyous."
Picture by Espenartman