As you move faster, time slows down for you. Even though that’s true when you’re riding in a car, the slowdown is so teeny-tiny that it’s not worth measuring. But, if you were to travel to another galaxy at almost the speed of light, time would slow down—for you—to the point where you would age more slowly than your pals back on Earth.
When you got back from your trip, your friends would be old and wrinkly but you’d be ready to graduate from high school.
Back to the beginning of The Western Civ User’s Guide to Time & Space