Carl Sagan

Carl Sagan was one of the most well-known scientists of the 1970s and 1980s. Sagan helped to popularize science through the writing of hundreds of articles and over two dozen books. In 1975, he won a Pulitzer Prize for his book "The Dragons of Eden." His television series "Cosmos" was one of the most watched shows in public television history, and has been seen by more than 500 million people in 60 different countries. Scientists have paid tribute to Sagan's deathless phrase "billions and billions," by naming a unit of measurement after him. The sagan is a number equal to at least 4 billion.