Activity 3: What is your time? The faster you move in space, the slower you move in time. Suppose a space traveler in a spaceship passed by you at a whooping speed, almost the speed of light. The space traveler, in his clock, measured a time elapsed of one second. Will you measure the same elapsed time? Why? Why not?
You might think that the time measured by the spaceman and your measured time should not matter. However, the time for each frame of reference really matters. One of the consequences of Einstein's postulates of the Special Theory of Relativity is the stretching of time. If we agree that the laws of Physics are the same for all observers in inertial reference frames and that the speed of light is constant, then it would only be possible that time is not absolute. This means that observers in different frames will observe and experience time in different ways. Time then becomes something personal for every observer. Very odd indeed! We call this time dilation. How much time stretches can be derived using simple geometry. Here is the equation:
This equation is not as scary as it appears. You just have to remember what each letter represents:
- t0: proper time (In the frame of reference moving with the clock)
- t: relative time (Another frame of reference not with the moving clock)
- v: speed of the clock (Relative to the outside observer)
- C: speed of light (This is constant. You can use 3.0 x 10^8)