Carl Sagan Biography - American Astronomer, Planetary Scientist, Cosmologist, Astrophysicist
Carl Sagan - Pale Blue Dot
This Speech Will Change Your Life | Carl Sagan
Carl Sagan - 'A Glorious Dawn' ft Stephen Hawking (Symphony of Science)
Carl Sagan warning about Donald Trump in 1994
Carl Edward Sagan 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.