Known for his vast contributions in the field of astronomy and biology, Carl Sagan went on to work for the University of California-Berkley, Harvard, and even the Smithsonian. In his later years, he won the Pulitzer Prize for his work on examining the atmospheres of other planets.

Born in New York City, the young Carl became obsessed with learning about the night sky and the stars that were just beyond his reach. His interest sustained throughout his adolescence and he went on to receive not only a BA in astronomy, but also a PhD in 1960. Thereafter, he served several academic posts and became director of Cornell University’s Laboratory for Planetary Studies. Furthermore, he worked with NASA in the United States, serving on a counsel that was directly involved in the examination and eventual space-probe missions to study several planets.

Going against the modern scientific belief of his day that Venus was a cool planet which might sustain life, Sagan explained that the planet could be the exact opposite – one that was extremely hot and one that would not sustain life. Scientists were searching for a reason why charged particles, or radio emissions were being found in its atmosphere. Sagan concluded further that if the planet had an extreme surface temperature, the radio signals would actually be a natural part of the carbon dioxide being trapped in the atmosphere. A probe sent by the Soviet Union proved his theories correct. Sagan proved a similar theory about the surface of Mars, when he concluded that the light and dark spots on the planet were canyons and high ridges bombarded with constant dust storms.

Carl Sagan entered the public limelight with his book The Cosmic Connection in which he promoted the use of space exploration for the search of life elsewhere in the universe. His Dragons of Eden, a book about the evolution of the human mind and intelligence, won him the Pulitzer Prize. In his work, he also warned about how nuclear capabilities on Earth would cause its eventual destruction.

• Edwin Hubble
• Robert Goddard
• Isaac Newton
• Galileo Galilei
• Copernicus