Jack_:
That's the first time I've heard anybody say that.
so what
So, since I am highly educated about relativity and it seems a little strange to me that you are using terminology that I have never come across in relation to relativity.
What do you mean when you say two frames are co-located? Recall that a reference frame extends throughout the whole of space.
I mean the same thing as is the case when Einstein with his R of S experiment claimed two frames were co-located.
Can you please post an extract of a reference where Einstein claims two frames are co-located?
No. The emission point of a light pulse, as I explained to you, is a fixed point in spacetime. It does not move.
Oh? So exactly where is this point?
We will need it because SR contends that emission point is the one used to decide t = d/c for a multitude of frames.
I want you to explain this.
Ok. No problem.
You have to be careful in distinguishing events and objects from coordinate systems.
Here's a simple analogy: Put your chair somewhere in the middle of the room you're in, but not at the centre of the room. Now, my question is: where is the chair, precisely?
One answer (A) might be: "The chair is 2 metres from the west wall and 1.3 metres from the North wall."
Another answer (B) might be: "The chair is 3 metres from the east wall and 3.7 metres from the South wall."
Suppose the room is 5 metres by 5 metres in size.
Next question: did the chair move between answers (A) and (B)? The answer, as you should be able to see, is "No". The chair stayed in exactly the same position. What happened was that the
coordinate system used to specify the chair's location moved, or to put it another way (A) and (B) use two different coordinate systems to describe the same object.
Similarly, in relativity, when you describe an event in spacetime, you can use two different coordinate systems (one specific to each reference frame), but that doesn't affect where the event is located in spacetime.
Does that make sense to you?