Carl Sagan
Born November 9, 1934
Died December 20, 1996

Perhaps the most well-known scientist of the latter half of the twentieth century, Carl Sagan was an astrophysicist, an astronomer, and a popularizer of science. According to the official Carl Sagan Portal, his official title for much of his scientific career “was the David Duncan Professor of Astronomy and Space Sciences and Director of the Laboratory for Planetary Studies at Cornell University.” He wrote close to twenty books, often with various coauthors including his wife Ann Druyan. Many of these books were written to help educate and popularize science, skepticism, and critical thinking.

Sagan was responsible for the discoveries of several new findings about our universe. Among them include determining the nature of Venus, and then discovering the reason Venus has such a nature; why Mars appears to have seasonal changes, finding evidence for a subsurface ocean within the moon of Europa, and many other facts. Sagan, interestingly, collected many of his incorrect hypotheses and theories concerning the planets in a chapter of his later books. In addition to these findings, he was instrumental in helping NASA find ways of probing the universe. He helped design the Galileo, Viking, Mariner, and Voyager missions, all of which returned to us incredible new data about our solar system.

For those not directly involved in the astrophysics community, Sagan is best remembered for his advocacy of the scientific method, his admonitions of the dangers of science used improperly, and his support for the search for extraterrestrial life. He always tried to help the world understand the necessity of science, the need for rationality and skepticism, while at the same time pointing out the dangers that science running unchecked could cause. He fought against the nuclear arms escalations in the 1980s, and argued that Reagan's Strategic Defense Initiative was worthless and would work against ending the crisis of the Cold War. Sagan strongly supported attempts to contact life beyond our planet, and helped get the Search for Extraterrestrial Life going strongly. He was responsible for the creation of several messages to the stars from earth, in the hope that someone somewhere would reach them, and talk back to us. This thought is what forms the basis of his lone work of fiction, Contact.