When was the American astronomer, cosmologist, astrophysicist, astrobiologist died who's introduction is in The Space Gods Revealed?
Carl Sagan 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. He is best known for his work as a science popularizer and communicator. His best known scientific contribution is research on 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 the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.
Steven J. Dick Steven J. Dick (born October 24, 1949, Evansville, Indiana) is an American astronomer, author, and historian of science most noted for his work in the field of astrobiology. Dick served as the Chief Historian for the National Aeronautics and Space Administration from 2003 to 2009 and as the Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology from 2013 to 2014. Before that, he was an astronomer and historian of science at the United States Naval Observatory in Washington, DC, from 1979 to 2003.