Twin paradox (Pete and MacM)

[MacM]

Or better yet, take two clocks neither is motion, but clock A runs at .229 the rate of clock B and is modulated with a 229KHz carrier. I receive at clock "B", do the division...

Result? 1 tick per second! But clock "A" in this scenerio is running slower that clock "B".

Since any time dilation would effect the carrier frequency by the same factor as the clock, you would get a "1 tick per second" answer with your system whether time dilation occurs or not.

The only way your system "proves" that both clocks run at the same rate is to assume universal absolute time.

So just as you cannot prove SR with SR, you cannot prove universal time by assuming universal time.

I could only accept your opinion if you were to agree that the simultaneity issue is a matter of information delay between the clocks, which I effectively by-passed by employing a digital signal which is bassed on physical time in reality.

And how do you explain the above scenario using the video tapes? The entire scenario is palyed out assuming relativity and is recorded.

Result? Both tapes are exactly alike (same length in feet and same time play on the same recorder at the same speed) when compared after the fact of having seen Relativity's time dilation carried out.

Both observers saw the supposed time dilation. The entire scenario is allowed to flow per relativity and the result is no actual shift in reality for time.

 

[James R]

MacM:

I have been struggling to find a way to make you see that your suggested "calibration" method is useless. It seems that Janus58's example is an excellent one to make my point.

Suppose that clock A is wildly inaccurate, and ticks once every 0.01 seconds. If clock B, running accurately, was sitting beside A, stationary, then for every 1 tick of B, there would be 100 ticks of A. Now, with the clocks still sitting on the bench, let A send a modulated signal to B at a frequency of 0.229 MHz, modulated at 0.0229 MHz. There are 10 waves per modulation in A's signal, and the signal frequency is unimportant.

B receives the signal from A, divides the carrier frequency by the modulation frequency and gets the number 10. B then says "Ah! 10 means I need to set my clock to 1 tick per second", and B does that.

Is clock B now running at the same rate as clock A? Of course not. A is still running 100 times faster than clock B.

This method quite clearly fails to synchronise the clocks. If you can't understand that at this stage, we really have no hope of making any further progress with this, and might as well quit now.

You said to Janus58:

I could only accept your opinion if you were to agree that the simultaneity issue is a matter of information delay between the clocks, which I effectively by-passed by employing a digital signal which is bassed on physical time in reality.

In the explanation I just gave, there is no significant signal delay. At all times the clocks are sitting right next to each other on the bench. Yet they still end up running at different rates. The lack of calibration is clearly not due to signal delays.

Even if you calibrated the clocks while they were together and then sent them off in relative motion, your procedure could not guarantee that they would be calibrated when in motion, because the information you send in your procedure doesn't reflect anything useful about the actual rates at which the clocks run.

In my next post, I will address your misconceptions about relativity, which are a separate issue, in more detail.

 

[James R]

MacM:

I have two clocks, neither in motion but in addition to what I have
done in this system, after modulating the 1 MHz carrier at "A" I pass the
signal through a frequency converter and reduce its frequency to 229KHz and
transmit. I receive it at clock "B", I do the division and applly the number 10 to the digital to frequency converter which is running on "B's" 1MHz carrier frequency.

Result? 1 tick per second.

Result: One tick per second, as determined by whatever clock B measures as 1 second, which may have no relationship to A's measure of 1 second.

The assumption you are making is exactly the thing you are setting out to prove. So, you're begging the question, arguing in a circle.

You can't start by assuming what you want to show. That's doing exactly the same thing you keep going on about. It is like trying to prove relativity using relativity. I think we can both agree you can't assume in advance what it is you are setting out to prove.

It does not matter that the frequency is shifted by electronics or
Relativity, the process loop regenerates the actual signal as it is in reality.

I have already explained that this may not be the case. It is pointless to repeat the explanation yet again.

Me: But notice that B can only set his clock by referencing his own
clock. He knows that he has to set his monitor to 1 tick per second,
but how does he measure a second? He has no information from A on how long a second is. He only has his own clock to determine how long a second
is.

You: Absolutely, unless you are now going to argue that "B's" proper time
has changed? Of course not he is still at 1 MHz the common standard
between clocks. Relativity does not allow changes in the local proper time or
any other component of its physics. That is a hall mark of Relativity.

B's proper time is simply the time measured by B's local clock. We can agree that doesn't change. But here we are trying to synchronise two different clocks, which may each have their own local times. We cannot assume in advance that those local proper times are the same, as you are trying to do. That is begging the question.

All physics in "B's" inertial frame are identical to the physics of "A's"
inertial frame although there is relavistic velocity between them.

Not true. All the laws of physics have the same form for both A and B, but A and B can still measure different values of physical parameters such as time. This is a simple misunderstanding of the relativistic postulates.

Lets reduce this arguement to something easier to see. Lets forget all
about light signals, timing, frequency changes, ratios codes, etc.

Lets simply calibrate two clocks and install on them a digital display which
shows tick rate. Now from deep space moving at any velocity I view
clock "A" with a high power scope. What does "B" now see "A's clock rate as?

B sees A's clock running slower, due to the relativistic Doppler shift which we have agreed on previously. (More about this in my next post.)

If it still reads 1 tick/second (which it will) then its accumulated time must be the same as it was at rest.

According to it, yes. According to an observer in relative motion... That is yet to be established (and relativity says no).

Physics are the same in all inertial frames. The physics cannot change
based on another frames view. Your view of his physics, certainly I
will accept that but not a change in physics reality.

The physics do change. It is only the forms of the laws of physics which do not change.

If observer A sees a mass m acted on by force F, then A will be able to calculate the acceleration using a=F/m. An observer B in relative motion will also be able to calculate an acceleration a'=F'/m', using the same form-invariant law, but there is no guarantee at all that a'=a, F'=F or m'=m. In fact, quite often these things are different for different observers.

 

[James R]

MacM:

For comparison with relativity, I would like to show you how your scenario would actually work in a Newtonian universe with absolute time and no relativity of simultaneity. Hopefully, by showing you this, we can separate issues of relativity from issues of signal delay and so on, and show you that they are completely separate.

A world with universal time

So, let's assume that there is a universal time t. At time t=0, clocks A and B are sychronised. Clock B moves at 0.9c in the positive x direction relative to A, while A remains stationary (from A's point of view). A emits a signal at 1 MHz, which is received by B and used to calibrate B's monitor of A's clock.

First question: In the Newtonian universe, what frequency does B receive?

The answer is given by the following formula.

f = fo / (1 + v/c)

If fo = 1 MHz, then

f = 1 MHz / (1 + 0.9) = 0.526 MHz.

So B receives a lower frequency than A sent. Why? Doppler shift. The formula quoted is the non-relativistic Doppler shift formula. There are no effects of relativity in this observed shift - only the effects of relative motion.

B has received a signal of 0.526 MHz. We want B's monitor of A's clock to tick at the same rate as A's clock, so what do we do? Easy. A frequency of 0.526 MHz means 526000 waves per second are received from A, as measured on B's local clock. So, for every 526000 waves B receives from A, B must increase the A clock monitor by one tick (one second).

Thus, we have a system by which B can monitor A's clock simply by counting the number of waves received from A and dividing by 526000 to get the number of seconds to display on B's monitor of A's clock.

There are no relativistic effects in this.

Note that in calibrating B's monitor, B had to account for the signalling delay caused by his relative motion away from A.

The relativistic universe

How does the above situation change in the relativistic world?

The most glaring thing we notice is that, under exactly the same conditions, B no longer receives a frequency of 0.526 MHz from A. Instead, he receives a frequency of 0.229 MHz. The relevant formula is the relativistic formula for the Doppler shift:

f = fo sqrt[(1 - v/c)/(1 + v/c)]

which, for v=0.9c, fo = 1 MHz, gives:

f = 1 MHz sqrt[(1-0.9)/(1+0.9)] = 0.229 MHz.

A very simple question to ask is: when you do an actual real-world experiment, which Doppler shift formula is found to be correct for light? Experimentally, do we find that the Newtonian formula is correct, or is it the relativistic one? Answer: the relativistic one is found to be correct. There is no doubt at all about this. The two formula give quite different results, as you can see, and actual experimental tests have been done which very accurately measure the frequency shift.

How is the figure of 0.229 MHz explained in relativity, then?

Well, notice the following fact:

0.229 MHz = 0.526 MHz / 2.294

What is this 2.29 number, do you suppose, and where does it come from?

The relativistic gamma factor for a speed v is:

g = 1/sqrt(1 -(v/c)²)

which in this case gives:

g = 1/sqrt(1 - (0.9)²) = 2.294

So, the observed frequency difference between the Newtonian solution and the relativistic one is:

f(Relativity) = f(Newton) / gamma

How do we account for this? The Newtonian picture, with its universal time, has already taken into account all the signal delay problems caused by the relative motion, yet the relativistic answer is STILL different.

-----------
Let's take time out for a minute to review your argument, MacM. You have been claiming in this thread that the effects of relativity are entirely explainable as a perceptual effect, due to signal delays. Yet what I have shown you here is that even after all signal delays have been factored out of the problem, there is STILL a remaining discrepancy between the relativistic Doppler shift and the Newtonian one. There can be only one conclusion:

Whatever causes the relativistic Doppler shift is only partially due to signal delays. We can't account for the entire shift using only signal delays alone.
-----------

So, why is there a gamma factor come into the equation above?

Answer: relativistic time dilation.

That is, even AFTER B factors out the signal delay caused by his motion relative to A, he still needs to introduce an extra factor of gamma to properly synchonise his monitor of A's clock. Why? Because B sees A's clock as running SLOWER than his.

It is quite clear that this effect is completely separate from the relative motion effects. We have discussed the relative motion effects when we looked at the Newtonian case. Newton only accounts for part of the observed rate difference. Einstein accounts for the rest.

Since the relativistic Doppler shift formula is unambiguously supported by actual experiments, you have no alternative but to accept that relativistic time dilation exists. Therefore, we conclude that there is no such thing as universal time.

 

[James R]

MacM:

Your example with the astronauts is simply the familiar twin paradox all over again. It doesn't add anything to the current discussion which is not already covered by examination of the two clock problem.

Therefore, I see it is an unnecessary distraction, and won't discuss it now.

 

[MacM]

MacM:

I have been struggling to find a way to make you see that your suggested "calibration" method is useless. It seems that Janus58's example is an excellent one to make my point.

Suppose that clock A is wildly inaccurate, and ticks once every 0.01 seconds. If clock B, running accurately, was sitting beside A, stationary, then for every 1 tick of B, there would be 100 ticks of A. Now, with the clocks still sitting on the bench, let A send a modulated signal to B at a frequency of 0.229 MHz, modulated at 0.0229 MHz. There are 10 waves per modulation in A's signal, and the signal frequency is unimportant.

B receives the signal from A, divides the carrier frequency by the modulation frequency and gets the number 10. B then says "Ah! 10 means I need to set my clock to 1 tick per second", and B does that.

Is clock B now running at the same rate as clock A? Of course not. A is still running 100 times faster than clock B.

This method quite clearly fails to synchronise the clocks. If you can't understand that at this stage, we really have no hope of making any further progress with this, and might as well quit now.

You said to Janus58:



In the explanation I just gave, there is no significant signal delay. At all times the clocks are sitting right next to each other on the bench. Yet they still end up running at different rates. The lack of calibration is clearly not due to signal delays.

Even if you calibrated the clocks while they were together and then sent them off in relative motion, your procedure could not guarantee that they would be calibrated when in motion, because the information you send in your procedure doesn't reflect anything useful about the actual rates at which the clocks run.

In my next post, I will address your misconceptions about relativity, which are a separate issue, in more detail.

Of course you MUST be aware of what you have just tried to do. You make the assumption that the initial calibration matching the clocks or the subsequent operation of a clock fails and because of that you come back and say "See it doesn't work".

Please stick with the stated scenario where the clocks are calibrated to be identical before the test and remain calibrated and functional throughtout the test.

 

[James R]

I agree that the clocks can be calibrated before the test. But we need to ensure that their respective monitors STAY calibrated once we move the clocks away from each other. Your procedure does not do that. My procedure would do that.

 

[MacM]

MacM:

Result: One tick per second, as determined by whatever clock B measures as 1 second, which may have no relationship to A's measure of 1 second.

The assumption you are making is exactly the thing you are setting out to prove. So, you're begging the question, arguing in a circle.

You can't start by assuming what you want to show. That's doing exactly the same thing you keep going on about. It is like trying to prove relativity using relativity. I think we can both agree you can't assume in advance what it is you are setting out to prove.

False. The clocks are calibrated to 1MHz common standard while both are at rest. There is no basis in physics or Relativity to suggest the local frequency in any way changes. Are you going to now state that it does? I'm waiting to see that desperate step.

I have already explained that this may not be the case. It is pointless to repeat the explanation yet again.

And I have given an apropriate answer which has not been shown invalid.

B's proper time is simply the time measured by B's local clock. We can agree that doesn't change. But here we are trying to synchronise two different clocks, which may each have their own local times. We cannot assume in advance that those local proper times are the same, as you are trying to do. That is begging the question.

False. If you think I have not sustained that point here then consider the case I presented using video recorders which travelled through Relavistic time recording all the time dilation Relativity predicts and the end results shows I am correct. Both times remained the same in terms of physical reality neither twin gets younger, and time is undilated but is only being shifted through perception of the time flow.

Not true. All the laws of physics have the same form for both A and B, but A and B can still measure different values of physical parameters such as time. This is a simple misunderstanding of the relativistic postulates.

B sees A's clock running slower, due to the relativistic Doppler shift which we have agreed on previously. (More about this in my next post.)

According to it, yes. According to an observer in relative motion... That is yet to be established (and relativity says no).

The physics do change. It is only the forms of the laws of physics which do not change.

If observer A sees a mass m acted on by force F, then A will be able to calculate the acceleration using a=F/m. An observer B in relative motion will also be able to calculate an acceleration a'=F'/m', using the same form-invariant law, but there is no guarantee at all that a'=a, F'=F or m'=m. In fact, quite often these things are different for different observers.

But you fail to realize a' is only an observation (perception) of a's value and is not involved in the physics perse'. The a' perception did not alter the physics of a.

 

[James R]

MacM:

The clocks are calibrated to 1MHz common standard while both are at rest.

Agreed. Both the local clocks are calibrated to tick at the same rate while both are at rest. What we aim to examine with this test is whether the clocks remain calibrated once they start moving.

You can't just assume they do. That is the whole point of the test.

There is no basis in physics or Relativity to suggest the local frequency in any way changes. Are you going to now state that it does? I'm waiting to see that desperate step.

I have already agreed that the proper or local frequencies do not change. A always measures 1 MHz for his own broadcast beam. B always measures 1 MHz for his own broadcast beam. What is at issue is whether B always measures 1 MHz for A's broadcast beam, and how this affects B's monitoring of A's clock (and vice versa).

We have already clearly established that B does not measure A's beam as being a 1 MHz beam. B measures it as being a 0.229 MHz beam.

My post above explains how B accounts for the shift in frequency.

False. If you think I have not sustained that point here then consider the case I presented using video recorders which travelled through Relavistic time recording all the time dilation Relativity predicts and the end results shows I am correct. Both times remained the same in terms of physical reality neither twin gets younger, and time is undilated but is only being shifted through perception of the time flow.

As I said, the bait and switch tactic will not work here. The VCR example is in essence no different from the original scenario, and you're not adding anything new by introducing it. You bring all the same misconceptions to the VCR problem that you bring to the original problem. So, let's stick with the original problem until we sort it out. Then we can discuss any other situations you wish to raise, including the VCR one.

But you fail to realize a' is only an observation (perception) of a's value and is not involved in the physics perse'. The a' perception did not alter the physics of a.

But you are arguing, without any support, essentially that a=a' at all times for all observers. That is wrong in the case of a and a', and it is equally wrong in the case of the times displayed on clocks A and B.

 

[MacM]

MacM:

For comparison with relativity, I would like to show you how your scenario would actually work in a Newtonian universe with absolute time and no relativity of simultaneity. Hopefully, by showing you this, we can separate issues of relativity from issues of signal delay and so on, and show you that they are completely separate.

A world with universal time

So, let's assume that there is a universal time t. At time t=0, clocks A and B are sychronised. Clock B moves at 0.9c in the positive x direction relative to A, while A remains stationary (from A's point of view). A emits a signal at 1 MHz, which is received by B and used to calibrate B's monitor of A's clock.

First question: In the Newtonian universe, what frequency does B receive?

The answer is given by the following formula.

f = fo / (1 + v/c)

If fo = 1 MHz, then

f = 1 MHz / (1 + 0.9) = 0.526 MHz.

So B receives a lower frequency than A sent. Why? Doppler shift. The formula quoted is the non-relativistic Doppler shift formula. There are no effects of relativity in this observed shift - only the effects of relative motion.

B has received a signal of 0.526 MHz. We want B's monitor of A's clock to tick at the same rate as A's clock, so what do we do? Easy. A frequency of 0.526 MHz means 526000 waves per second are received from A, as measured on B's local clock. So, for every 526000 waves B receives from A, B must increase the A clock monitor by one tick (one second).

Thus, we have a system by which B can monitor A's clock simply by counting the number of waves received from A and dividing by 526000 to get the number of seconds to display on B's monitor of A's clock.

There are no relativistic effects in this.

Note that in calibrating B's monitor, B had to account for the signalling delay caused by his relative motion away from A.

The relativistic universe

How does the above situation change in the relativistic world?

The most glaring thing we notice is that, under exactly the same conditions, B no longer receives a frequency of 0.526 MHz from A. Instead, he receives a frequency of 0.229 MHz. The relevant formula is the relativistic formula for the Doppler shift:

f = fo sqrt[(1 - v/c)/(1 + v/c)]

which, for v=0.9c, fo = 1 MHz, gives:

f = 1 MHz sqrt[(1-0.9)/(1+0.9)] = 0.229 MHz.

A very simple question to ask is: when you do an actual real-world experiment, which Doppler shift formula is found to be correct for light? Experimentally, do we find that the Newtonian formula is correct, or is it the relativistic one? Answer: the relativistic one is found to be correct. There is no doubt at all about this. The two formula give quite different results, as you can see, and actual experimental tests have been done which very accurately measure the frequency shift.

How is the figure of 0.229 MHz explained in relativity, then?

Well, notice the following fact:

0.229 MHz = 0.526 MHz / 2.294

What is this 2.29 number, do you suppose, and where does it come from?

The relativistic gamma factor for a speed v is:

g = 1/sqrt(1 -(v/c)²)

which in this case gives:

g = 1/sqrt(1 - (0.9)²) = 2.294

So, the observed frequency difference between the Newtonian solution and the relativistic one is:

f(Relativity) = f(Newton) / gamma

How do we account for this? The Newtonian picture, with its universal time, has already taken into account all the signal delay problems caused by the relative motion, yet the relativistic answer is STILL different.

-----------
Let's take time out for a minute to review your argument, MacM. You have been claiming in this thread that the effects of relativity are entirely explainable as a perceptual effect, due to signal delays. Yet what I have shown you here is that even after all signal delays have been factored out of the problem, there is STILL a remaining discrepancy between the relativistic Doppler shift and the Newtonian one. There can be only one conclusion:

Whatever causes the relativistic Doppler shift is only partially due to signal delays. We can't account for the entire shift using only signal delays alone.
-----------

So, why is there a gamma factor come into the equation above?

Answer: relativistic time dilation.

That is, even AFTER B factors out the signal delay caused by his motion relative to A, he still needs to introduce an extra factor of gamma to properly synchonise his monitor of A's clock. Why? Because B sees A's clock as running SLOWER than his.

It is quite clear that this effect is completely separate from the relative motion effects. We have discussed the relative motion effects when we looked at the Newtonian case. Newton only accounts for part of the observed rate difference. Einstein accounts for the rest.

Since the relativistic Doppler shift formula is unambiguously supported by actual experiments, you have no alternative but to accept that relativistic time dilation exists. Therefore, we conclude that there is no such thing as universal time.

First let me correct something you have repeatedly said. You keep referring to doppler shift as information delay. Doppler Shift is not information time delay. Doppler Shift is only a measure of relative velocity.

I'll prove my point. I transmit a 1 MHz signal. You recieve that signal but at 0.229MHz.

Question: What is our distance of seperation and amount of information delay.?

If you had been listening closely you would have heard in fact that I have not challenged the mathematics. I have and still do with your interpretation that the inclusion of Relativity Time Dilation is a change in physical reality and not simply perception caused by "Actual" delay of information. That delay has nothing to do with doppler shift.

The bottom line is that your Relavistics mathematics do not prove a time alteration in any manner. Indeed my video recorder shows that time flow of the twins are identical tick by tick from birth to death. The tapes are the same length running at the same speed on the same VCR.

We saw the affect of information delay while the video's were being recorded but the reality was that time flowed at the exact same rate for both twins.

 

[MacM]

MacM:

Your example with the astronauts is simply the familiar twin paradox all over again. It doesn't add anything to the current discussion which is not already covered by examination of the two clock problem.

Therefore, I see it is an unnecessary distraction, and won't discuss it now.

Well I very much take exception. It does indeed contribute. It is not the infamous twin paradox. In the twin paradox you claim an actual shift in ages in the twins. These video recorders seem to disagree with that assessment.

Please address the issue of the video tapes in the final analysis having been the exact same length when played on the same VCR at the same speed. They show the twins at simultaneous birth, they show your "Time-Dilation" issue. I have not rejected Relativity, the production of the videos show that affect.

But upon conclusion after the twins death, review of these tapes provides that time was not actually physically altered in any way. Both twins died at the same age and their lives consumed the same amount of real time per a common standard.

The apparent time dilation during production is as I have been trying to show nothing more than a perception of time flow and not an actual change of time flow.

It is like saying a 1 hour real time movie about some process, played in "Slow Motion" changes the length of the process. It doesn't it only changes the rate that you view the movie. In real time the process took 1 hour. It is still a 1 hour movie.

Although I might not be fully convienced that certain things will actually occur per Relativity I am and have not argued that they don't. I have and do argue that you are mis-interpreting what it means if it does.

i.e - perception vs reality.

 

[James R]

MacM:

First let me correct something you have repeatedly said. You keep referring to doppler shift as information delay. Doppler Shift is not information time delay. Doppler Shift is only a measure of relative velocity.

I'll prove my point. I transmit a 1 MHz signal. You recieve that signal but at 0.229MHz.

Question: What is our distance of seperation and amount of information delay.?

You can't calculate distance from Doppler shift alone.

As for information delay, if you receive 229000 waves every second instead of 1 million waves per second, then you have received less information in a given amount of time. That much is obvious.

If you had been listening closely you would have heard in fact that I have not challenged the mathematics.

The mathematics say simultaneity is relative. The mathematics says there is no universal time. The mathematics says time dilation occurs. Since you disagree with all these things, you MUST be challenging the mathematics.

I have and still do with your interpretation that the inclusion of Relativity Time Dilation is a change in physical reality and not simply perception caused by "Actual" delay of information.

I can't tell what this sentence means. I assume you've left out some words. Please try again.

The bottom line is that your Relavistics mathematics do not prove a time alteration in any manner.

Correct. The mathematics alone is just a model. What PROVES the time dilation etc. is that the mathematics gives a correct prediction of actual experimental results.

Indeed my video recorder shows that time flow of the twins are identical tick by tick from birth to death.

It shows no such thing. All it shows is that the proper times experienced by both twins are the same. It says nothing useful about whether particular events in the twins lives (such as their 50th birthdays, for example) occur simultaneously or not.

The tapes are the same length running at the same speed on the same VCR.

As measured locally. As measured by the other twin, the tapes run at quite different speeds.

We saw the affect of information delay while the video's were being recorded but the reality was that time flowed at the exact same rate for both twins.

You have not shown that. To do so would require that you compare the twins clocks while the recordings are happening. And to do that would require some experimental setup such as the 2 clock setup we started off with. Which brings us back to the original problem.

Let's drop this irrelevant twin example. It will only result in doubling the length of posts we need to resolve the issues here. All the basic issues are the same in both experiments, and, quite frankly, I can't be bothered explaining everything twice in two superficially different contexts.

 

[MacM]

MacM:

Agreed. Both the local clocks are calibrated to tick at the same rate while both are at rest. What we aim to examine with this test is whether the clocks remain calibrated once they start moving.

You can't just assume they do. That is the whole point of the test.

False. There is nothing in Relativity to suggest a change in calibration of either clock. Relativity merely states that B's view of A's clock reads differently than A reads his clock. From the get go you have a case of perception and not a change in calibration of clocks. If clock calibration changed then clock time would physically be wrong due to the relative motion of some observer. It would be intersting to see the clocks calibration and accumulated time with 10,000 moving observers at different velocities.

I have already agreed that the proper or local frequencies do not change. A always measures 1 MHz for his own broadcast beam. B always measures 1 MHz for his own broadcast beam. What is at issue is whether B always measures 1 MHz for A's broadcast beam, and how this affects B's monitoring of A's clock (and vice versa).

I have agreed B sees A's beam and clock data differently. That is not at issue. The issue is the difference between calling that reality vs perception since neither A or B clock change their accumulated times in reality..

We have already clearly established that B does not measure A's beam as being a 1 MHz beam. B measures it as being a 0.229 MHz beam.

My post above explains how B accounts for the shift in frequency.

No arguement. But it is perception not a change in A's time in physical reality.

As I said, the bait and switch tactic will not work here. The VCR example is in essence no different from the original scenario, and you're not adding anything new by introducing it. You bring all the same misconceptions to the VCR problem that you bring to the original problem. So, let's stick with the original problem until we sort it out. Then we can discuss any other situations you wish to raise, including the VCR one.

This is no bait and switch. It is very much on point and makes more clear than ever that time does not change. Please address the fact that after recording, even showing your time dilation affects, the two tapes are of identical lengths, palyed at the same speed on the same recorder.

HINT: Time didn't change, it was perception like viewing the 1 hour video of a process in slow motion. Doing so gives the illusion the process has changed but it didn't actually change the speed of the rocess. It is an illusion, not reality.

But you are arguing, without any support, essentially that a=a' at all times for all observers. That is wrong in the case of a and a', and it is equally wrong in the case of the times displayed on clocks A and B.

I haven't said that at all. I have said that the difference between "a' " and "a" is perception not reality, not that they remain equal mathematically in a distorted perception of the physics. We can apply your F=ma example in the 1 hour movie case. Video record a physics test of F = ma for an hour. Now play that video in slow motion. have you changed the process?

Of course not, you have only changed your perception of the F = ma test.

 

[James R]

Sorry, I just saw your latest post.

Please address the issue of the video tapes in the final analysis having been the exact same length when played on the same VCR at the same speed. They show the twins at simultaneous birth, they show your "Time-Dilation" issue. I have not rejected Relativity, the production of the videos show that affect.

But upon conclusion after the twins death, review of these tapes provides that time was not actually physically altered in any way. Both twins died at the same age and their lives consumed the same amount of real time per a common standard.

I agree with everything except the last sentence here.

The twins indeed died at the same subjective age. And their lives did indeed consume the same amount of subjective time for each of them. But it does not follow at all that this means there is some kind of universal time which applies to both of them.

Say, for example, that one twin waits until his biological age (measured somehow through cell degradation or whatever) indicates 1 year has passed. Then he takes the time measured on a mechanical clock he carries with him and divides his biological age advancement by the mechanical time. What does he find? Surprise! He seems to age 1 biological year for every timed year on his clock.

But does this mean that the twin will age 1 biological year for every timed year on somebody else's clock (say, an observer in relative motion)? Not at all. And that's the crux of the issue here. We're comparing the times measured by different observers, not the same observer.

It is like saying a 1 hour real time movie about some process, played in "Slow Motion" changes the length of the process. It doesn't it only changes the rate that you view the movie. In real time the process took 1 hour. It is still a 1 hour movie.

No! Not at all.

For an observer watching the movie in slow motion, it REALLY IS longer than 1 hour. If he measures the time it takes to watch the movie, it really does take longer than an hour. But for the person in the movie, the elapsed time on that person's watch is only an hour.

How do we account for the difference? We quite correctly conclude that the movie person's watch is running slow relative to the watcher's watch.

The reason for this in the movie case has to do with mechanical effects only. In the relativistic case, of course, there is a much more fundamental reason, tied up with the nature of space and time themselves.

Before you jump on this and go back to claiming that it is all just perception due to signal delays, bear in mind that I have already shown you that relativistic doppler shift is not just due to such delays. Hence, something more is needed than the type of mechanical explanation which works for the slowed movie.

I know I'm going to regret giving you this example, because I'm sure you'll ignore all the qualifications I've made here, and all the subtleties, and crow about how this somehow disproves relativity.

To avoid further bait-and-switch tactics on your part, I will tell you in advance that I have no intention at all of expanding any further on this movie example.

 

[James R]

MacM:

False. There is nothing in Relativity to suggest a change in calibration of either clock. Relativity merely states that B's view of A's clock reads differently than A reads his clock.

I posted a lengthy post showing that you are wrong only a couple of hours ago.

If we lived in a universe with absolute time, then we would expect one value of the shift in the rate at which A's clock seems to tick from B's point of view. That can be calculated using the Newtonian Doppler shift formula. But, as I showed, when we have factored out that shift, we are still left with an additional effect. That effect (time dilation) is accounted for perfectly by the theory of relativity.

So, it is correct to say: "Relativity merely states that B's view of A's clock reads differently than A reads his clock."

But Newton's theory of absolute time ALSO "merely" states that B's view of A's clock reads differently than A reads his clock.

The important point is that relativity correctly explains to what extent B's view of A's clock differs from his own, while Newton does not.

It's not simply a matter of the effect itself, but the precise nature of the effect.

If the answer was all in the perception of the moving observer, then Newton's laws would account for the entire effect. But they do not. Even after we've factored out the perceptual effects of signalling delays, something else remains: time dilation.

From the get go you have a case of perception and not a change in calibration of clocks. If clock calibration changed then clock time would physically be wrong due to the relative motion of some observer. It would be intersting to see the clocks calibration and accumulated time with 10,000 moving observers at different velocities.

There's no such thing as "physically wrong" when you're talking about relative times. The times are correct as long as one observer can correctly derive any other observer's time, given his own and the relative state of motion. Relativity allows him to do that, for 2 clocks or for 10000 clocks. Newtonian absolute time does not.

I have agreed B sees A's beam and clock data differently. That is not at issue. The issue is the difference between calling that reality vs perception since neither A or B clock change their accumulated times in reality..

The perception is factored out in the Newtonian analysis. That still leaves a real discrepancy. How do you account for that?

 

[MacM]

Sorry, I just saw your latest post.



I agree with everything except the last sentence here.

The twins indeed died at the same subjective age. And their lives did indeed consume the same amount of subjective time for each of them. But it does not follow at all that this means there is some kind of universal time which applies to both of them.

Now that is a mouth full that would take some explaining.

****"their lives did indeed consume the same amount of subjective time for each of them. But it does not follow at all that this means there is some kind of universal time which applies to both of them"*****

You agree that there lives take the same amount of actual time but that that doesn't prove universal time?

Say, for example, that one twin waits until his biological age (measured somehow through cell degradation or whatever) indicates 1 year has passed. Then he takes the time measured on a mechanical clock he carries with him and divides his biological age advancement by the mechanical time. What does he find? Surprise! He seems to age 1 biological year for every timed year on his clock.

But does this mean that the twin will age 1 biological year for every timed year on somebody else's clock (say, an observer in relative motion)? Not at all. And that's the crux of the issue here. We're comparing the times measured by different observers, not the same observer.

The video tapes disagree with your conclusion. They show in fact that whatever is the cause of the affect in Relativity it must be perception and not a physical change in time.

No! Not at all.

For an observer watching the movie in slow motion, it REALLY IS longer than 1 hour. If he measures the time it takes to watch the movie, it really does take longer than an hour. But for the person in the movie, the elapsed time on that person's watch is only an hour.

That is because the process (the person in the movie where the process was recorded is real time and not an observers perception of his time. Your perception is certainly longer than an hour but it (in real time) is still a 1 hour movie. Distortion of reality (called perception) is over an hour but not the actual process being recorded.

How do we account for the difference? We quite correctly conclude that the movie person's watch is running slow relative to the watcher's watch.

That is a most obvious error. While it might be a great illusion and caused you to think the process had been miss tested and you go and have the watch tested you find out that the watch works just fine, that it was the VCR (Relativity) that screwed up the perception of the test.

The reason for this in the movie case has to do with mechanical effects only. In the relativistic case, of course, there is a much more fundamental reason, tied up with the nature of space and time themselves.

This frankly is a very poor escape goat excuse. It doesn't fly. It is unjustified. There is no basis what-so-ever to inject it. The video tape proceedure is an absolute proof of my point. You cannot now start to make up magic where Relativity works in some strange way beyond mechanics.

These affects are all about mechanics (i.e. - the person's watch in the movie). There is no priori to make such a claim. You are desperate. I can tell. That is good.

Before you jump on this and go back to claiming that it is all just perception due to signal delays, bear in mind that I have already shown you that relativistic doppler shift is not just due to such delays. Hence, something more is needed than the type of mechanical explanation which works for the slowed movie.

Hardly. You have mislabled doppler shift as signal delay. It isn't. Time dilation and signal delay are the same thing and they aren't doppler shift.

There is nothing more needed (unless of course you need something more to continue to argue your point). Good luck at finding it. The video tapes played right in concert with your Relativity. It was not ignored.

Result: "their lives did indeed consume the same amount of subjective time for each of them."

Time was not altered, the perception of time flow was altered. There exist therefore a universal time in reality.

I know I'm going to regret giving you this example, because I'm sure you'll ignore all the qualifications I've made here, and all the subtleties, and crow about how this somehow disproves relativity.

Well, I'm not crowing but I certainly am looking to see a valid explanation to my question. I haven't seen one yet.

To avoid further bait-and-switch tactics on your part, I will tell you in advance that I have no intention at all of expanding any further on this movie example.

This is not a bait and switch. You have already agreed that this is the same situation we have been discussing. I just realized it is a bit more direct and to the point, making the issue very much clearer.

Now if you are looking for a dodge (which your comments here seem to be doing, saying that their is more to this than the mechanical functions of the video recorder", then this is your opportunity, since I see this as the better of the two presentations. It is clean, simple and to the point without frequencies, doppler shift, simultaneities, ratios, etc, etc.

This is very direct and to the point.

Now that you have agreed that the twins lives comsumed the same amount of universal time, even with one flying around at high relavistic velocity, why don't you just acknowledge that Relativity is a perception and not physical reality?

You complained that you don't want to challenge or respond to two themes at the same time. I agree with that but you are deliberately picking the wrong theme. I am more than willing to stop the discussion on clocks and concentrate on the video tapes.

It is easier and requires no math and makes the point in a very clear way.

 

[Pete]

One-Off.

What is being sent is at "A" its (using James R's frequencies) 1 MHz carrier is modulated by a 100KHz frequency which corresponds to a tick rate of 1/second. That is 10 carrier pulses per second = 1 tick/sec and an accuracy out to 1 decimal place. 1 tick/2 seconds would be modulated at 50KHz, etc.

Upon receipt by "B" receeding at 0.9c the carrier would be received at 0.229MHz (229KHz) with a modulated side band of 0.0229MHz (22.9KHz)

229/22.9 = 10 (unitless) that encoded 10 tells "B" "A's" true tick rate. That signal is applied so as to set the monitor counter of "A" to 1 tick per second by calibration via "B's" local 1 MHz carrier frequency.

So, B knows that A's clock is still running locally at 1MHz, and A's local tick rate is still 1 tick per second.

But that ratio doesn't seem to tell B anything about A's tick rate in B's frame? The carrier frequency does, but not the ratio.


If SR were true, and simultaneity is relative, what sort of modulated signal do you think B would receive from A, and why?

 

[MacM]

So, B knows that A's clock is still running locally at 1MHz, and A's local tick rate is still 1 tick per second.

But that ratio doesn't seem to tell B anything about A's tick rate in B's frame? The carrier frequency does, but not the ratio.


If SR were true, and simultaneity is relative, what sort of modulated signal do you think B would receive from A, and why?

I do believe that has been covered. Both A and B transmit carriers at 1 MHz and both receive the others beams as 0.229MHz. The side modulation based on a 10 to one ratio means the modulation frequency is 100KHz by both clocks and each clock receives the modulation as 0.0229MHz. Still 10/1.

Applied to B's local and A's local 1MHz beam establish true clock rate of the other clocks as 0.229Mhz/0.0229MHz = 10/1.

The 1 tick/second clock rate, which is applied to the monitor using the local 1 MHz carrier.

The result B's view of A and A's view of B are not shifted (dilated) each sees the others clock running in their real time, which will correspond exactly with each other when such clocks are brought back together. i.e. the twin did not get younger or age slower in reality.

 

[Pete]

You agree that there lives take the same amount of actual time but that that doesn't prove universal time?

"Subjective time". Not "Actual time". They're not necessarily the same thing, if you want "actual" to mean "universal".

I know you believe that they are the same thing, but can you prove it?

 

[MacM]

"Subjective time". Not "Actual time". They're not the same thing, if you want "actual" to mean "universal".

Just to clarify. "Actual" is to mean "Universal". If they and "Subjective" are not all equal lthen the tapes would necessarily be of different lengths.

It is only the perception of viewing these tapes at less than the actual flow rate that crreates the illusion of time dilation.