Carl Edward Sagan (; November 9, 1934 – December 20, 1996) was an American
astronomer,
cosmologist,
astrophysicist,
astrobiologist, author, science popularizer, and
science communicator in astronomy and other natural sciences. His contributions were central to the discovery of the high surface temperatures of
Venus. However, he is best known for his contributions to the scientific research of
extraterrestrial life, including experimental demonstration of the production of
amino acids from basic chemicals by
radiation. Sagan assembled the first physical messages that were 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.