Carl Edward Sagan (November 9, 1934 to December 20, 1996) was an American astronomer, planetary scientist 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 exposure to light. He published more than 600 scientific papers and articles, and was author, co-author or editor of more than 20 books, including the bestseller, The Dragons of Eden. The following recording is Sagan's 1985 testimony before the US Congress on climate change.