Einstein's special theory of relativity, points out that any movement of the inertial system measured a inertial frames to two events with is not the same as the time interval is greater than its natural time, this is the so-called clock slow effect. The movement of the relativity, two relative motion relative to the other party objects of the passage of time are slow, this in some specific circumstances appeared contradictions. But at the same time, by the clock slow effect can also get some more meaningful