Admiral Grace Hopper joined the U.S. Navy in 1944 at the age of 37. She was one of the first programmers of the Harvard Mark I computer and wrote the first compiler for a computer programming language. When asked by Letterman how she knew so much about computers then, Hopper responds: “I didn’t. It was the first one”. In this video, Admiral Hopper explains to David Letterman what a nanosecond is: “When an admiral asks you why it takes so damn long to send a message via satellite, you point out to him that between here and the satellite there are a very large number of nanoseconds”.