Carl Edward Sagan (1934 –1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is his research on the possibility of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued in favor of the hypothesis, accepted since, that the high surface temperatures of Venus are the result of the greenhouse effect.
Sagan was a popular public advocate of skeptical scientific inquiry and the scientific method; he pioneered the field of exobiology and promoted the search for extra-terrestrial intelligent life (SETI). He spent most of his career as a professor of astronomy at Cornell University, where he directed the Laboratory for Planetary Studies.
Sagan and his works received numerous awards and honors, including the NASA Distinguished Public Service Medal, the National Academy of Sciences Public Welfare Medal, the Pulitzer Prize for General Non-Fiction (for his book The Dragons of Eden), and (for Cosmos: A Personal Voyage), two Emmy Awards, the Peabody Award, and the Hugo Award.