Let us see a bar on the ground. We go around the bar and find its length in our tranverse direction(x) and length in longtitudinal direction (y) varies according to what angle to the bar we are. Bar Length^2 = x^2 + y^2 is kept constant during our walk.Time dilation can be shown mathematically but what is the physical phenomenon due to which it occurs?
First of all, it cannot be shown mathematically. It's shown physically.Time dilation can be shown mathematically but what is the physical phenomenon due to which it occurs?
I like the perspective it's the geometry of spacetime; however that is one step after the most favored irreducible reply, that c is invariant. Am surprised no one mentioned causality. That's a fun one to think of as being the cause of time dilation / length contraction.I know that things do not actually change size in their reference frames but only is observed to be doing so. I am asking if time dilation occurs due to the time taken by the light to reach us or something of that sort.
There's also the Block Universe interpretation:There's no physical phenomenon, its a point-of-view phenomenon. It's like asking "when I look at circle head-on, it looks like a circle, but when I view it from an angle, it looks like an ellipse. What is the physical phenomenon which causes this?"
Different inertial frames have different "points of view", they divide spacetime up into space and time in different ways. People in different inertial systems disagree about the time between two events in the same way people viewing a circle at different angles will disagree on what it looks like. They both understand why they disagree, just as relativity explains why two inertial systems may disagree.
I would have mentioned causality and other things but I was too busy to comment and the thread has gone on for a while now.I like the perspective it's the geometry of spacetime; however that is one step after the most favored irreducible reply, that c is invariant. Am surprised no one mentioned causality. That's a fun one to think of as being the cause of time dilation / length contraction.
For a simply put book on SR, Relativity (a brief insight) by Russell Stannard is one I like. He put's a fair amount of emphasis on measurement (in turn perspectives); which I find important when developing an understanding of the concept in general.
"Hermann Minkowski developed the concept of three-dimensional space combined with time to form a four-dimensional space-time. The importance of this concept is that... the effect of relative movement... appears in the same manner as does the effect of a rotation in three-dimensional space." -- Dr. Ron DavisIt sounds like you are invoking a mechanical metaphor by using the word rotation, but I can't follow what you are saying (and I am not implying that is your fault). Can you clarify?
Coordinate transformation for rotation is given by, say ##\theta## is rotaion angle,appears in the same manner as does the effect of a rotation in three-dimensional space."