Time Dilation

Time dilation is a different passing of time for two different reference frames, a reference frame being any non accelerating frame, such as a room or a car travelling at 60 mph. The theory says that if a spaceship were to zoom past you at a very high speed, you would see its onboard clock tick more slowly than it should. For whoever is on the ship, though, everything would be normal, time would pass as it should. The implication is that the person standing watching the ship will age faster than the person travelling on the fast ship. This will affect our global positioning system in a very significant manner when we explore that later.