A Brief History of Time: From the Big Bang to Black Holes

Stephen William Hawking was born in Oxford, England on January 8, 1942. He received a first class honors degree in natural science from Oxford University and a Ph.D. from Cambridge University. He was a theoretical physicist and has held the post of Lucasian Professor of Mathematics at Cambridge University from 1982 until his death. In 1974, he was elected a Fellow of the Royal Society, the world's oldest scientific organization. In 1963, he learned he had amyotrophic lateral sclerosis, a neuromuscular wasting disease also known as Lou Gehrig's disease. The disease confined him to a wheelchair and reduced his bodily control to the flexing of a finger and voluntary eye movements, but left his mental faculties untouched. He became a leader in exploring gravity and the properties of black holes. He wrote numerous books including A Brief History of Time: From the Big Bang to Black Holes, Black Holes and Baby Universes, On the Shoulders of Giants, A Briefer History of Time, The Universe in a Nutshell, The Grand Design, and Brief Answers to the Big Questions. In 1982, he was named a commander of the British Empire. A film about his life, The Theory of Everything, was released in 2014 and was based on his first wife Jane Hawking's book Traveling to Infinity: My Life with Stephen. He died on March 14, 2018 at the age of 76.

A respected planetary scientist best known outside the field for his popularizations of astronomy, Carl Sagan was born in New York City on November 9, 1934. He attended the University of Chicago, where he received a B.A. in 1954, a B.S. in 1955, and a M.S. in 1956 in physics as well as a Ph.D. in 1960 in astronomy and astrophysics. He has several early scholarly achievements including the experimental demonstration of the synthesis of the energy-carrying molecule ATP (adenosine triphosphate) in primitive-earth experiments. Another was the proposal that the greenhouse effect explained the high temperature of the surface of Venus. He was also one of the driving forces behind the mission of the U.S. satellite Viking to the surface of Mars. He was part of a team that investigated the effects of nuclear war on the earth's climate - the "nuclear winter" scenario. Sagan's role in developing the "Cosmos" series, one of the most successful series of any kind to be broadcast on the Public Broadcasting System, and his book The Dragons of Eden (1977) won the Pulitzer Prize in 1978. He also wrote the novel Contact, which was made into a movie starring Jodie Foster. He died from pneumonia on December 20, 1996.