In exclusive interviews, Stephen Hawking, NASA leaders, and Nobel Prize-winning astronomers talk about how their discoveries have affected life's big questions.

If we send a message into space, will extraterrestrial beings receive it? Will they understand? The endlessly fascinating question of whether we are alone in th

“Fascinating . . . memorable . . . revealing . . . perhaps the best of Carl Sagan’s books.”—The Washington Post Book World (front page review) In Cosmos

Discusses activities astronauts do while they're in space.