# Why the phenomenon of relativity is not progressive in nature.

1. Jun 14, 2012

### PressMan

My Question is, “why the phenomenon of relativity is not progressive in nature”. For example we say that a person moving with ‘c’ faces the time dilation say t. But since the person is still in inertial frame (constant velocity or zero acceleration) and also moving with ‘c’ with new time why he didn’t see another time dilation. My means if it occurs then his time will shift from t to say t1 which will be far slower than t. Tell me reason.
Thanks.

2. Jun 14, 2012

### DaveC426913

You must be exact in what reference point you use and who does the observing.

A person p moving with respect to a chosen reference point (say a moon) at speed s will experience no time dilation in his own frame of reference (you are always stationary in your own frame of reference), but he will see time dilation of things that are not in his frame of reference.

For example, if p looked down upon the moon, moving by at speed s, he would see the people m there with time dilation t.

At the same time, the people m of the moon are looking up and seeing p zoom by at speed s experiencing time dilation t.

What you cannot do is try to look through the eyes of someone else moving in a different frame of reference. So p can't look through the eyes of m and see himself.

3. Jun 14, 2012

### FroChro

The theory of special relativity does tell us how to transform from one inertial frame to another. Imagine spacetime like some kind of "objective" reality with its points corresponding to events. You as observer want to label these points using coordinates. You label each event with three space coordinates and one time coordinate. In the case you have done this in "a standard way" and you were not accelerating the theory tells you how another inertial observer moving with respect to you would label them. (Those points/events.)

What I am trying to say using all this "unclear terminology" are three things:
1. Theory tells us how different (inertial) observers would label the events using "the standard or natural way".
2. Because we are talking about labeling events using some kind of (here unspecified) standard/natural way, it tells us how those observers *see* the spacetime/reality.
3. Because the theory tells us how to transform from one inertial frame to another, it also tells us how differently different inertial observers perceive the spacetime. For example if you have to events in spacetime you can tell what is their (coordinate) distance in time and space according to different observers.

So there is no "absolute" time dilatation or any other relativistic effect. You as an observer, no matter how you move, as long as you do not accelerate, will see just "normal" spacetime. There will be no time dilation or any contraction "per se". These effects results only because different observers see things differently.