Abstract
While space is measured directly, time is measured indirectly through an event. In general, we use a periodic event to measure time. We only need to count the number of periods between the starting point and the ending point of the event. In other words, we measure time through frequency. To investigate whether time dilates at a speed approaching light speed, it is convenient to study the behavior of periodic events at such a high speed. In the present paper, we discuss time dilation by means of thought experiments (in German: Gedankenexperimente) involving periodic events occurring aboard a spaceship traveling at a speed approaching the speed of light. We conclude that the two postulates of Special Relativity simply cannot coexist. (C) 2017 Physics Essays Publication.