Related by context. Frequent words. (Click for all words.) 67 Carl Sagan 58 Richard Feynman 52 Feynman 50 Buckminster Fuller 48 Albert Einstein 48 Neil deGrasse Tyson 48 James Lovelock 47 Reinhold Niebuhr 47 Niels Bohr 47 Mandelbrot 47 Dr. Jonas Salk 47 Linus Pauling 46 Professor Stephen Hawking 46 Sigmund Freud 46 HG Wells 45 Edwin Hubble 45 Voyager spacecraft 45 Edward Teller 44 Bertrand Russell 44 Johannes Kepler 44 Isaac Asimov 44 Norman Vincent Peale 44 Terkel 44 Einstein 44 Wernher von Braun 44 Michael Crichton 44 Kurt Vonnegut 44 Horkheimer 44 Lindzen 44 Timothy Leary 44 Jacques Derrida 44 Arthur Schlesinger Jr. 44 Jeremy Rifkin 43 Friedrich Engels 43 Nikola Tesla 43 Galileo Galilei 43 Jonas Salk 43 Osamu Tezuka 43 Clyde Tombaugh 43 Professor Hawking 43 Ray Kurzweil 43 Daniel Dennett 43 Astrophysicist 43 Aleksandr Solzhenitsyn 43 Jane Goodall 43 interplanetary spacecraft 42 Walter Lippmann 42 Francis Crick 42 Steven Pinker 42 physicist Stephen Hawking 42 Calvin Trillin 42 science fiction novels 42 Dom DeLuise 42 Premier Zhou Enlai 42 Stephen Hawking 42 Revkin 42 Thomas Alva Edison 42 extraterrestrials 42 Dick Cavett 41 Ram Dass 41 Boorstin 41 Aldous Huxley 41 astronomer 41 Randy Pausch 41 Walter Cronkite 41 astrobiologists 41 Thomas Malthus 41 Swami Vivekananda 41 Isaac Bashevis Singer 41 Ralph Waldo Emerson 41 Carl Jung 41 Theodor Herzl 41 Isaac Newton 41 classical antiquity 41 mathematician 41 alien civilizations 41 Susan Sontag 41 Gene Roddenberry 41 physicist 41 Roland Barthes 40 Rebecca Solnit 40 Stanley Kubrick 40 Michael Shermer 40 Harlan Ellison 40 Louis Pasteur 40 physicists 40 Halley Comet 40 Rod Serling 40 Grace Paley 40 Zhou Enlai 40 Betty Friedan 40 Nobel Laureate 40 Nobel Laureates 40 Alexis de Tocqueville 40 Brahe 40 author Toni Morrison 40 Seracini 40 Andrei Sakharov 40 Allen Ginsberg 40 Nobel Prize winners 40 Michael Beschloss