What do the movies Peggy Sue Got Married, X-Men, Men in Black 3, Star Trek IV, and Back to the Future have in common?The same thing the novels A Christmas Carol, Rip Van Winkle, and Harry Potter and the Prisoner of Azkaban have in common. They all feature time travel, a popular device in film and fiction.Time travel overcomes the limits of reality. Like the ancient human desire to fly, time travel frees us from one of the basic limitations of existence—and least for as long as it takes to finish the book or movie.There’s precious little chance that science will
