In his Theory of Relativity, Einstein said that as a body approaches the speed of light, time slows down. Most people accept this without explanation because; it has been proven, by physicists, as true. Still, the reason escapes the average person. It needs a metaphor and the best one I know of was in the comedy “Young Einstein” with YAHOO SERIOUS playing the titular role.
In the movie, Young Einstein is at rest beside the face of a giant clock at noon. Suddenly, both Einstein and the face of the clock are fired off at the speed of light. When Einstein glances over at the face of the clock, it still reads noon, therefore he is NOT aging. If he should slow down, the clock would read 12:01 0r 12: 02, the faces of the clock following behind noon, therefore, he would be aging but if he went faster than light (an impossibility) the clock would read 11:59 or 11:58, the faces of the clock before noon, and he would be getting younger.
Are you following this? If not, rent the movie and you’ll see what I mean. The concept, however, fascinates people and they play with it. Here is a perfect example of the philosopher’s Calvin and Hobbs exploring Einstein’s theory with hilarious results.