# Thread: Is time universal? NO (and its proof)

1. Originally Posted by Aer
Again, the reason is because of the relativity of simultaneity.
The reason doesn't really matter, but since I'm in the mood...
The satellite clock is not inertial in your example.
Correct. We're specifically talking about the satellite clock's rest frame. Not any particular instantaneous comoving frame.
As such, the satellite stationary clock did not start at the same time as the satellite clock in the instantaneous reference frame that the satellite is in upon meeting up with the satellite-stationary clock.
Correct. But the satellite stationary clock did start at the same start as the satellite clock in the satellite clock's rest frame - which is the frame under consideration.

The satellite clock does still think that the satellite stationary clock ticks slower than it's own clock.
That seems to be a pretty empty assertion (Much like "I have been the only one in this thread to accurately describe relativity". That's one of Mac's favourite lines, did you know?).
How exactly do you measure tick rates?

Anyway, like I said before it really doesn't matter. The physical effect is what matters, rather than the explanation.

So this is the important bit. The reasoning you ascribe to it is irrelevant, as long as you agree to the physical predictions:

Do you agree that SR predicts that less time elapses on the Satellite clock than the Satellite-Stationary clock between each meeting?

Do you agree that SR predicts that less time elapses on the Surface clock than the Surface-Stationary clock between each meeting?

2. Originally Posted by Aer
Originally Posted by Pete
and that the ratio of the two elapsed times is the same in all frames?
No, I do not agree. I don't have the will power to try to explain it, but I just simply do not agree with that statement.
That's your right, of course, but you've got to agree that it's pretty unconvincing, and also disappointing. I expected more from sciforum's most argumentative.

When the two clocks are at the same time and place, the two "ticks" of the two clocks at that meeting point are essentially the same event, so they're obviously simultaneous in all frames, right?

Eg if Satellite clock ticks to 10 and Satellite-Stationary clock ticks to 20 as they pass, then everyone agrees that Satellite clock ticked to 10 at the same time as Satellite-Stationary clock ticked to 20.

And if at a later meeting, Satellite clock ticks 20 and Satellite-Stationary clock ticks 35 as they pass, then those ticks are also simultaneous in all frames.

So, between those two meetings, all observers in all frames agree that 10 units passed on the Satellite clock while 15 units passed on the Satellite-Stationary clock.

Since this is a repeating relationship, it's clear that the Satellite clock will accumulate 2/3 the ticks that the Satellite-Stationary clock accumulates, and that this is true in all frames.

Now personally, I'd equate "accumulates fewer ticks over time" as "ticks at a slower rate", but you're welcome to not make that connection if you so desire.

3. Originally Posted by Pete
The reason doesn't really matter, but since I'm in the mood...
The relativity of simultaneity does matter and is the source of your error in stating that 1 clock ticks at a slower rate than the other clock in all frames. That is not right. The so called "tick rate" in a given frame is a function of the instantaneous velocity of each clock to said given frame.

Originally Posted by Pete
Correct. We're specifically talking about the satellite clock's rest frame. Not any particular instantaneous comoving frame.
This is what you don't understand. That frame is not inertial. As such, you can only analyze instantaneous frames for this clock.

Now please read the following very carefully because it is the heart of the difference between special relativity and MacM relativity (the following is true according to special relativity, what you have described is true according to MacM relativity):

As such, according to special relativity when the satellite clock meets back up with the stationary satellite clock, the events of the satellite clock and the stationary satellite clock starting simultaneous in the stationary satellite frame is not simultaneous according to the instantaneous frame of the satellite clock upon meeting back up with the stationary satellite clock. This loss of simultaneity of when the clocks started is what allows special relativity to state that each clock sees the other as slower than their own clock according to their respective rest frames.

4. Originally Posted by Pete
That seems to be a pretty empty assertion (Much like "I have been the only one in this thread to accurately describe relativity". That's one of Mac's favourite lines, did you know?).
You are taking what I said out of context, but I believe you did that unintentionally...

I only claimed to have correctly described special relativity as the theory is stated.

MacM claims to describe "relativity" correctly in reality which he claims is different from "special relativity". Specifically, I refer to his "relativity" as "MacM relativity". It seems that you have bought into MacM's relativity as you are trying to tell me that relativity behaves according to the rules of "MacM relativity" and not "special relativity". And I must say I am truely amazed by this.

5. MacM, you are in error as I suspected. Please see the discussion by Prof. Ashby here http://relativity.livingreviews.org/...es/lrr-2003-1/ for details.

6. Originally Posted by Pete
GR says that the orbiting clock's rest frame is inertial, but SR doesn't.
It was claimed here by James R that orbit is inertial in that it is in free fall. Technically it is not inertial however but is treated so for most applications.

SR says that the orbiting clock's rest frame is not inertial, and that in the orbiting clock's rest frame, the surface clock ticks faster (or less time elapses between specified events, if you prefer to think of it like that!)
I think this is where you are wrong. It is the reality but SRT claims the surface bound clock would tick slower. (GR disregarded).

7. Originally Posted by Aer
The relativity of simultaneity does matter
Of course. I never suggested otherwise.
I said that the reason for the difference in elapsed times doesn't matter - the fact of the elapsed times is what's important.
I notice it's what you ignored. Are you deliberately sidetracking to avoid talking about the actual physical predictions of SR?

Originally Posted by Aer
The so called "tick rate" in a given frame is a function of the instantaneous velocity of each clock to said given frame.
Spoken like a true rote learner.
"Tick rate", by definition, is the number of ticks per unit time, right?

Originally Posted by Aer
This is what you don't understand. That frame is not inertial. As such, you can only analyze instantaneous frames for this clock.
The irony is killing me. How many times have you "reminded" me that SR can handle accelerating frames? It's now clear that you just don't know how, do you?

Originally Posted by Aer
Now please read the following very carefully because it is the heart of the difference between special relativity and MacM relativity (the following is true according to special relativity, what you have described is true according to MacM relativity):

As such, according to special relativity when the satellite clock meets back up with the stationary satellite clock, the events of the satellite clock and the stationary satellite clock starting simultaneous in the stationary satellite frame is not simultaneous according to the instantaneous frame of the satellite clock upon meeting back up with the stationary satellite clock.
The events of the satellite clock and the stationary satellite clock starting simultaneous in the stationary satellite frame happened in the same place (the previous meeting), therefore they are simultaneous in all frames.

You do understand that two events that happens at the same place and time are simultaneous in all frames, don't you?

8. Since you missed the most important part, the part that's actually directly relevant to the discussion, I'll repeat it for you.

I need to know whether you agree to the physical predictions. It's not terribly important if we disagree on the causes of these predictions, but it is important that we agree on the physical predictions themselves:

Do you agree that SR predicts that less time elapses on the Satellite clock than the Satellite-Stationary clock between each meeting in all frames?

Do you agree that SR predicts that less time elapses on the Surface clock than the Surface-Stationary clock between each meeting in all frames?

Note that these questions are identical to asking whether less time elapses on the travelling twin's clock than the stay-home twin's clock in all frames.

You might also want to think more on the other post you ignored. I know it burns you up inside when you know that someone's wrong, but you just can't find where their mistake is... but can you try to work past it and just consider the possibility that perhaps I might actually be talking sense?

9. Originally Posted by Pete
Yers, of course it does, and I never suggested otherwise.
I said that the reason for the difference in elapsed times doesn't matter - the fact of the elapsed times is what's important, and I notice it's what you ignored.
I have not ignored any such thing. You just do not understand that acceleration breaks the simultaneity and it makes no sense to talk about "elapsed time" according to a non-inertial frame. In which frame does the "elapsed time" occur? The frame at the end of the acceleration? How about the frame at the start of the acceleration? Or maybe an average of the two as some kind of middle frame?

Originally Posted by Pete
Spoken like a true rote learner.
"Tick rate", by definition, is the number of ticks per unit time, right?
Yet again you fail to grasp what I was saying to you. I said so called "tick rate" becuase the "per unit time" requires an elapsed time which is ill-defined for a noninertial frame.

Originally Posted by Pete
The irony is killing me. How many times have you "reminded" me that SR can handle accelerating frames? It's now clear that you just don't know how, do you?
Wrong. I have correctly explained to you how to apply SR to accelerating frames on many occations. You just have your own incorrect ideas on how to approach such a problem (GR, I believe? ha, still makes me laugh) and as such you do not know how to properly do it with SR. This is very evident here as you are trying to assume the noninertial frame as the rest frame and speak of "elapsed times".

Originally Posted by Pete
The events of the satellite clock and the stationary satellite clock starting simultaneous in the stationary satellite frame happened in the same place, therefore they are simultaneous in all frames.
The reasoning here is just wrong on so many levels. Space and time are relative and different in all frames. How can you define a point in space/time as the same in all frames? Is your all not all inclusive?

10. Pete, you can ask the same questions over and over. But that isn't going to make the correct answer change.

I've given you the correct answer to all of your questions and explained exactly where you are going wrong. I'll leave it to James R or someone else to sort you out.

11. I have not ignored any such thing. You just do not understand that acceleration breaks the simultaneity and it makes no sense to talk about "elapsed time" according to a non-inertial frame. In which frame does the "elapsed time" occur? The frame at the end of the acceleration? How about the frame at the start of the acceleration? Or maybe an average of the two as some kind of middle frame?
Oh, so now you claim that the satellite's rest frame doesn't exist because it's not inertial?
By "elapsed time" I mean "how much time has passed on the satellite clock".
Don't you think that's a meaningful definition?

Elapsed time in a non-inertial frame is very well-defined, Aer. Does the satellite clock not tick because it's accelerating?

I have correctly explained to you how to apply SR to accelerating frames on many occations.
Hmmm... let me count... zero. I'll count again... yep, still zero.

Originally Posted by Aer
Originally Posted by Pete
The events of the satellite clock and the stationary satellite clock starting simultaneous in the stationary satellite frame happened in the same place, therefore they are simultaneous in all frames.
The reasoning here is just wrong on so many levels. Space and time are relative and different in all frames. How can you define a point in space/time as the same in all frames? Is your all not all inclusive?
Come on Aer, this is really basic stuff
Do you really think that if two events happen together (same time and place), that they don't happen together in all frames?

12. Originally Posted by Aer
Pete, you can ask the same questions over and over. But that isn't going to make the correct answer change.
Of course not... but you haven't given any answer yet...

Oh, that's right. You don't know what "elapsed time" means

Let's try again, with language you can (presumably) understand:

If the times on Satellite clock the Satellite-Stationary clock are recorded at a meeting, then recorded again at a later meeting, then is the difference between readings greater for the Satellite clock or the Satellite-Stationary clock?

13. You just have your own incorrect ideas on how to approach such a problem (GR, I believe? ha, still makes me laugh) and as such you do not know how to properly do it with SR.
GR can handle time dilations due to acceleration in flat spacetimes. So can SR. Agree?

14. Originally Posted by Pete
Oh, so now you claim that the satellite's rest frame doesn't exist because it's not inertial?
No, I've told you that you can not apply special relativity and talk about such things as "elapsed time". I'll note for you that within the framework of a "local ether" such things that you state such as "elapsed times" are clearly defined for an accelerating frame. They are not in special relativity, the simultaneity of events (such as the tick of a clock) is dependent on the instantaneous inertial frame you are in.

Originally Posted by Pete
By "elapsed time" I mean "how much time has passed on the satellite clock".
Don't you think that's a meaningful definition?
What is meaningful? SR is nonintuitive, remember? You are apply your intuition to relativity. Which as I've pointed out, your intuition seems to lead you to the "Local Ether" model.

Originally Posted by Pete
Elapsed time in a non-inertial frame is very well-defined, Aer. Does the satellite clock not tick because it's accelerating?
You are developing a good disproof of relativity.

Originally Posted by Pete
Hmmm... let me count... zero. I'll count again... yep, still zero.
That is exactly how many times you understood the explanation I gave you.

Originally Posted by Pete
Come on Aer, this is really basic stuff
Do you really think that if two events happen together (same time and place), that they don't happen together in all frames?
Does it matter what I think? I thought we were talking about relativity?

15. Originally Posted by James R
GR can handle time dilations due to acceleration in flat spacetimes. So can SR. Agree?
GR in flat spacetime is SR - so technically, yes I do agree.

But Pete believes there is some kind of pseudo-frames or something (I don't recall) that you can apply to GR that gives you a different explanation for time dilation than given by SR. This, I do not agree with and was what I was refering to.

16. Originally Posted by James R
GR can handle time dilations due to acceleration in flat spacetimes. So can SR. Agree?
Agree

17. Originally Posted by Pete
Of course not... but you haven't given any answer yet...
I've answered all your questions regarding all frames stating that one satellite has time dilated compared to the other satellite as NO. For clarification, this NO, means: YOU ARE WRONG.

18. Originally Posted by Aer
I've told you that you can not apply special relativity and talk about such things as "elapsed time".
Yes, I put that on my "Aer's unsupported assertions" list, and after due considereation transferred it to the "Aer's bullshit assertions" list.

Originally Posted by Aer
Do you really think that if two events happen together (same time and place), that they don't happen together in all frames? ”
Does it matter what I think? I thought we were talking about relativity?
If I wasn't interested in what you think, I'd be ignoring you.
Do you think that if two events happen together (same time and place), that they don't happen together in all frames?
Do you think that SR says that if two events happen together (same time and place), that they don't happen together in all frames?

19. Originally Posted by Aer
I've answered all your questions regarding all frames stating that one satellite has time dilated compared to the other satellite as NO. For clarification, this NO, means: YOU ARE WRONG.
So you are answering NO to this question?

Originally Posted by Pete
If the times on Satellite clock and the Satellite-Stationary clock are recorded at a meeting, then recorded again at a later meeting, then is the difference between readings greater for the Satellite clock or the Satellite-Stationary clock?
Then what do you answer to this question:

If the times on the travelling twin's clock and the travelling twin's clock are recorded before the traveller departs, then recorded again when the traveller returns, then is the difference between readings greater for the stay-home twin or the travelling twin?

20. Originally Posted by Pete
Yes, I put that on my "Aer's unsupported assertions" list, and after due considereation transferred it to the "Aer's bullshit assertions" list.
Do you know what is wrong with MacM's claims about comparing clocks for different frames? Comparing clocks requires they either meet or one accelerates to the frame of the other. In both situations, one frame is noninertial and as such has a shift of simultaneity.

It appears that you are in agreement with MacM that one clock is actually dilated compared to the other clock in all frames. This is one of MacM's famous claims against special relativity

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