Carl Edward Sagan (1934-1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, author, science communicator, and advocate for science and reason. He sought to explain the universe and the value of the scientific method to a broad audience.
Sagan made significant contributions to planetary science, including research on the atmosphere of Venus and the seasonal changes on Mars. He advised NASA, briefing Apollo astronauts and contributing to the Mariner, Viking, Voyager, and Galileo missions. He was also a pioneer in exobiology, exploring the possibility of extraterrestrial life, and he encouraged the search for extraterrestrial intelligence (SETI). Sagan's ability to communicate complex scientific concepts to the public led to his widespread recognition. His book Cosmos became a bestseller, and the Emmy and Peabody award-winning television series Cosmos: A Personal Voyage, which he co-wrote and narrated, was watched by over 500 million people in 60 countries. He also authored over 600 scientific papers and articles and more than 20 books.