Is Relativity Incorrect? Examining Motion and Perception Evidence

[Hurkyl]

Let's run some actual numbers.

Suppose your setup is 10m long. In the lab frame, all 6 (identical) clocks are stationary and set to 0.

A' is at the left end, M' is in the middle, and B' is at the right end.


Suppose that A', M', and B' are all accelerated in exactly the same way to a velocity of 1 m/s. In this moving frame, the clock readings are no longer synchronous; B' > M' > A'. In particular, according to the moving frame, when A' reads 0, M' reads 5.56 * 10^-17 seconds, and B' reads 1.11 * 10^-16 seconds.

Note that the descrepancy is less than a millionth of a nanosecond. The differnce between B' and A' is less than a millionth of the frequency of a Cs-133 atom. Hardly a surprise it should go unnoticed. Heck, NIST's clock is only accurate to about one part in 10^15, still not enough to detect the difference.

 

[ram2048]

uhhh

if they're all accelerated the same way (i'm assuming you mean same direction and rate of accel) why are they not synchro anymore?

 

[Hurkyl]

If they gave the same readings at the same time in the lab frame...
And they all underwent the exact same acceleration in the lab frame...
Then they still give the same readings at the same time in the lab frame.

But that is no reason to think they give the same readings at the same time in the moving frame, unless you've already assumed simultaneity is absolute.

 

[ram2048]

but why should you think that it isn't the same in the first place.

if all variables for the clocks are the same then how can the result be different

the only answer is there's some external effect happening that we haven't thought of

 

[Hurkyl]

if all variables for the clocks are the same then how can the result be different

They can't.

But, according to SR, there are very few frames where all of the variables are the same. The lab frame is one of them, (and thus the readings in the lab frame would remain synchronized)


In most other inertial frames, the readings were not synchronized before the acceleration began, and they remain unsynchronized when the acceleration finished.


And if you actually want to consider the accelerated frames of A', M', and B', it turns out that the fact that A' is accelerating towards B', but B' is accelerating away from A' is important; it's the temporal analog of centrifugal force.

 

[ram2048]

And if you actually want to consider the accelerated frames of A', M', and B', it turns out that the fact that A' is accelerating towards B', but B' is accelerating away from A' is important; it's the temporal analog of centrifugal force.

i don't think that makes a difference. they're both accelerating away from their starting positions at the same rate, it wouldn't matter what direction they were going in.

 

[Hurkyl]

Well, the general result is that in accelerated frames, observations of clocks are affected by more than just time dilation. In particular, if you're accelerating towards a clock, you perceive it running faster, and if you're accelerating away from a clock, you perceive it running slower (/stopped/backwards).

So in A''s accelerated frame, B' will run fast. However, in B''s accelerated frame, A' will run slow.

 

[ram2048]

sounds like doppler effect, not time dilation

you're intercepting the photons that say what time it is faster than a person who is stationary

you
1:00--------59----------58----------57-----------56----------55---------54-------53(o) <-- clock
guy

guy stays still and waits for the light from clock to hit him, thus registers time as standard.

you move towards the clock and intercept incoming light from clock sooner than him just by virtue of being closer

 

[geistkiesel]

I take it you're only considering the case when both photons came from the same direction, then? (I.E. you are not considering the case when the actual sequence of events goes something like "Pass A, see photon A, see photon B, pass B")

(P.S. I'm not faulting you for doing this; it is a fairly messy task to account properly for all the possibilities)


So the criterion for simultaneous emission, according to the moving observer, is that:

c * (y - z) = v (x - w)

Note that I think you have one of the sides reversed; if the moving observer passed A before B, then he should expect to get B's photon first if emission was simultaneous, making both sides positive. (And similarly if B was passed before A)


As an aside, this is a nifty equation, because it renders calculation of time dilation irrelevant; any sort of dilation of times cancels out!


So let's remember this criterion and go back into the stationary frame. We have an experimental setup consisting of two stationary lamps, A and B. We watch a moving observer pass by both lamps with velocity v, and then, by some means, we trigger A and B simultaneously.

Notice that, in particular, this corresponds to the previous setup; the moving observer will pass A, then pass B, then get B's photon, then get A's photon. Thus, let us compute the times these occur.

For simplicity, the stationary observer sets his clock to 0 when the moving observer passes A. Let's suppose A was at position 0, and B was at position p.

Then, the moving observer passes B at time p / v.

Let's trigger the lamps at time 2p/v. The moving observer is at position 2p when this happens...

Thus, it takes time p / (c - v) for the photon from A to reach him, and time 2p / (c - v) for the photon from A to reach him.

So we have the following: In our frame,
He passes A at time 0.
He passes B at time p/v.
He receives the photon from B at time 2p/v + p/(c-v)
He receives the photon from A at time 2p/v + 2p/(c-v)


Remembering from our aside that dilation is irrelevant for the criterion that the moving observer computes the emission to be simultaneous. Let's substitute the times into the equation:

c * (y - z) = v (x - w)

yielding

c * ((2p/v + 2p/(c-v)) - (2p/v + p/(c-v))) = v ((p/v) - 0)
simplifying...
c * p / (c-v) = p
cancel out p...
c / (c - v) = 1
et cetera...
c = c - v
v = 0

Since the observer is moving, this equation clearly cannot hold, thus we conclude the moving observer does not compute that A and B were activated simultaneously.

Maybe so. The simple model I used had the moving sorces passing by the stationary observer. He was able to make the determination that one or the other photons were emitted before the other. Do all the calulations you desire. The experiment I deswcribed in my summary still holds. If one measures the emission of the photons simulaneously then any theoretical construct that contradicts the expemenatl observation is flawed.

 

[geistkiesel]

Let's run some actual numbers.

Suppose your setup is 10m long. In the lab frame, all 6 (identical) clocks are stationary and set to 0.

A' is at the left end, M' is in the middle, and B' is at the right end.


Suppose that A', M', and B' are all accelerated in exactly the same way to a velocity of 1 m/s. In this moving frame, the clock readings are no longer synchronous; B' > M' > A'. In particular, according to the moving frame, when A' reads 0, M' reads 5.56 * 10^-17 seconds, and B' reads 1.11 * 10^-16 seconds.

Note that the descrepancy is less than a millionth of a nanosecond. The differnce between B' and A' is less than a millionth of the frequency of a Cs-133 atom. Hardly a surprise it should go unnoticed. Heck, NIST's clock is only accurate to about one part in 10^15, still not enough to detect the difference.

Your analysis is totally bogus. Come on Hurkyl. The A', M' and B' clocks are on the same rigid frame and are all accelerated together, at the same time. How in th e heck do you get the inequaliies you do? Do you make this up as you go along? It is the same train man. The clocks are just set at diffeent points in the train. Are you trying to be purposfully obscuring the hypothetical experiment in an attempt to confuse me or any observer to this thread?

 

[geistkiesel]

I take it you're only considering the case when both photons came from the same direction, then? (I.E. you are not considering the case when the actual sequence of events goes something like "Pass A, see photon A, see photon B, pass B")

(P.S. I'm not faulting you for doing this; it is a fairly messy task to account properly for all the possibilities)


So the criterion for simultaneous emission, according to the moving observer, is that:

c * (y - z) = v (x - w)

Note that I think you have one of the sides reversed; if the moving observer passed A before B, then he should expect to get B's photon first if emission was simultaneous, making both sides positive. (And similarly if B was passed before A)


As an aside, this is a nifty equation, because it renders calculation of time dilation irrelevant; any sort of dilation of times cancels out!


So let's remember this criterion and go back into the stationary frame. We have an experimental setup consisting of two stationary lamps, A and B. We watch a moving observer pass by both lamps with velocity v, and then, by some means, we trigger A and B simultaneously.

Notice that, in particular, this corresponds to the previous setup; the moving observer will pass A, then pass B, then get B's photon, then get A's photon. Thus, let us compute the times these occur.

For simplicity, the stationary observer sets his clock to 0 when the moving observer passes A. Let's suppose A was at position 0, and B was at position p.

Then, the moving observer passes B at time p / v.

Let's trigger the lamps at time 2p/v. The moving observer is at position 2p when this happens...

Thus, it takes time p / (c - v) for the photon from A to reach him, and time 2p / (c - v) for the photon from A to reach him.

So we have the following: In our frame,
He passes A at time 0.
He passes B at time p/v.
He receives the photon from B at time 2p/v + p/(c-v)
He receives the photon from A at time 2p/v + 2p/(c-v)


Remembering from our aside that dilation is irrelevant for the criterion that the moving observer computes the emission to be simultaneous. Let's substitute the times into the equation:

c * (y - z) = v (x - w)

yielding

c * ((2p/v + 2p/(c-v)) - (2p/v + p/(c-v))) = v ((p/v) - 0)
simplifying...
c * p / (c-v) = p
cancel out p...
c / (c - v) = 1
et cetera...
c = c - v
v = 0

Since the observer is moving, this equation clearly cannot hold, thus we conclude the moving observer does not compute that A and B were activated simultaneously.

Your hypothetical to me was confusing. You had the frame moving, then the observer. Any way all that is your problem. I am standing by the hyopothetical that have the photons observed to be emitted simultaneously. When you tire of your trivial calculations and want to discuss the experimental result, just say so.

edit added: If your source of photons is the same as the hypothetical arrangement that /b/measured[/b] the photons being emitted simultaneously then what ever your conclusions are merely adds a few more centimeters to the depth of the grave hole that is being dug for SR theory. Every SR analysis conflictingwith the experuimental results proves my point why continue? Your analysis above is just another shovel of dirt thrown out by that eternal and tireless worker, Dellawsa Fizzicks.

 

[geistkiesel]

Bogus physics

Let's run some actual numbers.

Suppose your setup is 10m long. In the lab frame, all 6 (identical) clocks are stationary and set to 0.

A' is at the left end, M' is in the middle, and B' is at the right end.


Suppose that A', M', and B' are all accelerated in exactly the same way to a velocity of 1 m/s. In this moving frame, the clock readings are no longer synchronous; B' > M' > A'. In particular, according to the moving frame, when A' reads 0, M' reads 5.56 * 10^-17 seconds, and B' reads 1.11 * 10^-16 seconds.

Note that the descrepancy is less than a millionth of a nanosecond. The differnce between B' and A' is less than a millionth of the frequency of a Cs-133 atom. Hardly a surprise it should go unnoticed. Heck, NIST's clock is only accurate to about one part in 10^15, still not enough to detect the difference.

Then make he train go faster and make it as long as mecessary. Your setting the clocks synchronization is totally bogus. The clocks are on the same frame man. The clocks are accelerated slowly together to reach a velocoty v = 1.

SR demands the simultaneous emission of photions in the stationar6y frame are nonsimulatneous whenread from the moving frame. Discuss the contradiction between experiment and theory. If you re able to do so.

Are you trying to toss in some of your confusion here in order to throw the direction of the thread away from the primary focus of ciontradiciton od theory by experimental results?:
Is this an honest effort on your part or are you playing the role of faithful propagandist??

 

[geistkiesel]

uhhh

if they're all accelerated the same way (i'm assuming you mean same direction and rate of accel) why are they not synchro anymore?

Uhhh.

They are all obeying the same law of physics. They are all on the same rigid frame when accelerated. The clocks are identical. There is no fram3e-to-frame synchroni=zsation.
The laws of physics are identical in all stationary frames are they not?
When you say "i'm assuming you mean same direction and rate of accel)" , you are telling me you haven't a clue to what the experimental conditions are.

Why don't you find out what is poing on here, or are you and Hurkyl just trying to confuse the observers and posters to this thread?

 

[geistkiesel]

If they gave the same readings at the same time in the lab frame...
And they all underwent the exact same acceleration in the lab frame...
Then they still give the same readings at the same time in the lab frame.

But that is no reason to think they give the same readings at the same time in the moving frame, unless you've already assumed simultaneity is absolute.

You mean that taking identical clocks and subjecting them to identical acceleration conditions will result in random clock dilations? What does simultaneity is absolute" mean anyway? Is this some random and incompetently formed physical enquiry?, or are you just trying to divert the thread away from the impending disaster of discovering that SR is flawed and useless physical construction?

I am assuming the constancy of he lasws of physics acting on identical bodies when acted upon in identical ways will result in identical results. Do you agree with this?

 

[geistkiesel]

but why should you think that it isn't the same in the first place.

if all variables for the clocks are the same then how can the result be different

the only answer is there's some external effect happening that we haven't thought of

It is apparent that the external effect you haven't thought of is the laws of physics. Why not review those?

You haven't addressed the primar issue here. you are trying to obscue the laws of physics, intetionally, or unintenionally. What is your problem?

 

[ram2048]

Uhhh.

They are all obeying the same law of physics. They are all on the same rigid frame when accelerated. The clocks are identical. There is no fram3e-to-frame synchroni=zsation.
The laws of physics are identical in all stationary frames are they not?
When you say "i'm assuming you mean same direction and rate of accel)" , you are telling me you haven't a clue to what the experimental conditions are.

Why don't you find out what is poing on here, or are you and Hurkyl just trying to confuse the observers and posters to this thread

actually i was just trying to get hurkyl to clarify his new "setup" before i tried to figure out what he was saying in his proposition.

not trying to confuse anyone, just trying to make things clearer for myself.

i've already explained the way i view the situation, need me to elaborate? it's pretty straightforward if you view it from a certain standpoint.

 

[geistkiesel]

Well, the general result is that in accelerated frames, observations of clocks are affected by more than just time dilation. In particular, if you're accelerating towards a clock, you perceive it running faster, and if you're accelerating away from a clock, you perceive it running slower (/stopped/backwards).

So in A''s accelerated frame, B' will run fast. However, in B''s accelerated frame, A' will run slow.

Why are you comparing acelerated clock readings? What possible significance does your speculations have on the expeimental results that proved the photons in the experiment that is the focus of the thread were emitted simultaneously?

GET BACK ON TRACK.

 

[geistkiesel]

actually i was just trying to get hurkyl to clarify his new "setup" before i tried to figure out what he was saying in his proposition.

not trying to confuse anyone, just trying to make things clearer for myself.

i've already explained the way i view the situation, need me to elaborate? it's pretty straightforward if you view it from a certain standpoint.

If you elaborate about the experimental esults that proved the photons were emitted simultaneously, OK. but why digress to some point that is not directed at the issue of the contradiction between expeimental results and SR theory?

 

[ram2048]

because i was trying to figure out where he was going with that line of thought.

he never comes out and directly says something (well seldomly). he'll throw up a crapload of subtlely linked hypotheticals at you and have you wear yourself out trying to solve them

then when you're weak and tired he'll dry-gulch you with what he had originally intended in the first place and you'll be too brain fried to refute it... :D

in any case please verify for me:

let's state our facts.

1. the clocks are not moving
2. the clocks will always face the observer
3. there is a defined midpoint between the two clocks
4. lightspeed is constant within the system

now our subject matter.

4. the clocks may or may NOT be synchronized.
5. the observer moves towards the midpoint from ANY direction at ANY speed
6. he reaches the midpoint at the EXACT time to view the same time displayed on both clocks

what can we conclude from this?

7. the clocks ARE synchronized

is that what we've been arguing about? because i don't see the problem...

 

[Hurkyl]

I am standing by the hyopothetical that have the photons observed to be emitted simultaneously.

And that's the whole problem. Your hypothetical is in direct violation of Special Relativity, thus you should be getting results that disagree with Special Relativity.

What does simultaneity is absolute" mean anyway?

Absolute simultaneity is precisely what you have been assuming: things are either simultaneous or they are not. It is not relative to anything.

The alternative is relative simultaneity which is part of SR. It only makes sense to speak about simultaneity relative to something (in SR's case, relative to the choice of reference frame).


For another example of "absoulte" vs "relative" consider that of position.

"Absolute position" means that I can give three numbers that unambiguously state where I am in the universe.

"Relative position" means that I can give three numbers that unambiguously state where I am, with respect to a chosen origin and choice of directions.

are you just trying to divert the thread away from the impending disaster of discovering that SR is flawed and useless physical construction?

Sort of like how you've steered the thread away from the example where I got you to explicitly state a condition for events to be simultaneous in a moving frame, and show that condition fails, despite the events being simultaneous in the stationary frame?

 

[Hurkyl]

1. the clocks are not moving
2. the clocks will always face the observer
3. there is a defined midpoint between the two clocks
4. lightspeed is constant within the system

now our subject matter.

4. the clocks may or may NOT be synchronized.
5. the observer moves towards the midpoint from ANY direction at ANY speed
6. he reaches the midpoint at the EXACT time to view the same time displayed on both clocks

what can we conclude from this?

7. the clocks ARE synchronized

is that what we've been arguing about? because i don't see the problem...

The problem is #1: the clocks are not moving. (and less so, #6 is a problem)

If #1 is false, one generally would not conclude the clocks are synchronized. This corresponds to the difference between the "moving" frame and the "stationary" frame; in the former the clocks are moving.

 

[geistkiesel]

The problem is #1: the clocks are not moving. (and less so, #6 is a problem)

If #1 is false, one generally would not conclude the clocks are synchronized. This corresponds to the difference between the "moving" frame and the "stationary" frame; in the former the clocks are moving.

Hurkyl

Quote:
1. the clocks are not moving
2. the clocks will always face the observer
3. there is a defined midpoint between the two clocks
4. lightspeed is constant within the system

now our subject matter.

4. the clocks may or may NOT be synchronized.
5. the observer moves towards the midpoint from ANY direction at ANY speed
6. he reaches the midpoint at the EXACT time to view the same time displayed on both clocks

what can we conclude from this?

7. the clocks ARE synchronized

is that what we've been arguing about? because i don't see the problem...

The problem is #1: the clocks are not moving. (and less so, #6 is a problem)

If #1 is false, one generally would not conclude the clocks are synchronized. This corresponds to the difference between the "moving" frame and the "stationary" frame; in the former the clocks are moving.

" You ask what can we conclude from this?"

You can conlcude anything you desire from this, I conclude that you have altered the experimenal arrangement wher the clocks on the moving frame and the clocks in the stationary frame are such that A = A', B=B' M = M' where M is the midoint between the photon sources. The clocks on each inertial frame[/size] are synchronized within each frame. As the moving frame passes the stationary frame with the locations as defined at that instant, photos were emitted and clock times noted within the frames and these noted times were exchyanged as a matter of courtesy to the other frame.

With the exception of the addition of the clocks and method of determining the instant the photons left A and B, by triggering that emission by the passing moving frame, Eisnteins example of he loss of simultaneity is faithfully recreted. maybe you have a quarrle with our manner of mesuring or the way in which we carefully considered the SR imperatives of time and matter shrinking in arriving ar=t the construction of the frame that guarantees A=A' B=B' and M = M" as coordinates for an instant, a mimimum quantum instant.

You say the clocks cannot be synchrionized? You mean the moving frame clocks and technology cannot determine a midpoint between the clocks, just like the stationary frame? You say the laws of physics are different for the moving frame? You say we cannot predict the time dilation and shrinking and build an oversized frame that will shrink to the dimensions such that A =A', B = B' and M =M' when achieving some velocity v =1? Prove it then, with more than 'it cannot be done'" statements.

If you want to casually ignore the laws of physics to suit your collpased SR theory reconstruction purposes, be reminded that in the moving frame we will synchronize those clocks the same way the statioanry frame synchronized their clocks, only with respect to the particlular frame. We aren't talking about frame-to-frame synchronization, is this understood? By synchronize I mean only that all clocks will measure the same time wherever located on the frame. If errors develop for any reason, such as through sabotage by unscrupulous SR Theorists, the error can be repaired, just like in the stationary frame.

What would an unscrupulous SR Theorist look like if suddenly ejected from a spaceship dressed only in his clothes? Would he be able to tell what time it was?

 

[geistkiesel]

because i was trying to figure out where he was going with that line of thought.

he never comes out and directly says something (well seldomly). he'll throw up a crapload of subtlely linked hypotheticals at you and have you wear yourself out trying to solve them

then when you're weak and tired he'll dry-gulch you with what he had originally intended in the first place and you'll be too brain fried to refute it... :D

I was brain fried the first time I went through this post. If nothing else I am becoming more aware as these posts continue, of the ol' dry-gulching scenario. I missed your candor assuming in my paranoia that all are the enemy. My humble apologies, it always a relief to meet another monk along the endless path.

Roses are red
violets are blue,
I'm schizophrenic,
and so am I
Herb Caen

Hell, I expect it. It makes me strong, as it is easier to point out a conscious cheater than merely one convinced honestly of their position. I did fall into the trap, my generous nature, to agree to anything my enemy proposes. He had me making calculations on how I would determine if the photons from two sources on moving frames emitted photons simultaneously. I thought my answer was rather trivially simple, but he was scuffing his toes in the dirt and clouded it up, or tried to.

Then it dawned on me, why I was so generous, I mean my only concern is to expose the contradiction between experiment and theory in the case of simultaneity among inertial frames. All the elaborate means I went through to build a situation where for only a single instant, A = A', B = B' and M = M' where the symbols are coordinates. This and the switch on the moving frame triggering photons simultaniously at A and B.

Now Hurkyl screams at me that the moving platform crosses M = M' with the frame pointed at any angle. He is denying me the switch I inserted that triggered the emission of the photons in both frames simultaneously. Damn, all that money and effort, to lose now because of the unexpected "any angle of motion through M" bushwhack. Well, I found out later that my instrumentation group had installed a switch at M that emitted a pulse at M that sent a signal to A and B to emit the photons at A and B when M = M' simultaneously, which is what occured. While the rest of the moving frame was passing through M, like an arrow, the photons from sources at A and B were detected at points along the moving frame arrow especially at the shortest distance from A and B which are symmetrically located. (inserted with a continuous line of photo diodes) at the same time, the same instant. (We have aslo added the "single emitted" photon restriction to accommodate a short pulse of photons.) All the detected points on the wave front of the photons from A and B were 100% consistent with simultaneous emission of the photons, measuring the spherical radiation of the photons emitted with detectors at A' and B'

While I was going around the M=M' point slowly rotating my moving frame arrow around M = M', it dawned on me that there would be a severe problem when the arrow was pi/2 to the directed line of motion of photons between A and B. Problem to Hurkyl, that is. All measurements along the arrow from tip to feather, lined as the shaft was, with the tiniest photo diode sensitive detectors possible, all measured all arriving photons from A and B simultaneously, for the duration of the continuous emission of the photon pulse. What else could the mesurement and theory determine? In the case of the theory, an exception, as here reality and theory agree, embarasssingly agree.

Hurkyl, you aren't supposed to stir up dust with your toes, you're supposed to draw a line in the sand, don't cha know?

Then I saw him, the enemy, lurking prone,
setting up another bushwhack,
when he found me alone.

So, with most careful arrow's aim I wait, to hurry?, oh no.
When speaks the last refrain then?
When I thrust home.


I will respond to the other half of your post post haste.

 

[Hurkyl]

We never get to talk about the results of your thought experiment becuase you continually deny SR in the setup of the experiment. You talk about things like instants of time, synchronized clocks, and simultaneous events, but in SR all of those things only have any meaning relative to some reference frame.


The primary way you've been misleading yourself with this thought experiment is the presence of multiple clocks per reference frame. Using your assumption that both sets of clocks will be synchronized, you are able to arrive at the conclusion you want.

Furthermore, you have avoided doing any sort of other calculations with your experimental setup; one of the main points of this thought experiment is that if you don't use relativity, you must measure the speed of light to be something other than c.


I had to, more or less, trick you into doing one of these computations. You did a good job of computing a criterion for the moving observer to identify whether the photons were emitted simultaneously, so you're certainly capable of doing these sorts of calculations.

I wasn't stirring up dust, I was handing you rope.

Unfortunately, I was too impatient and opted to derive the final result myself instead of getting you to derive it, leading to the predictable result that you simply ignored the results without any sort of critical reasoning whatsoever. It seemed you felt the need to heap on some insults to rationalize this behavior, though, which I take as a good sign.


I do find it peculiar that you have been writing the last couple of pages as if you have actually performed an actual, physical experiment.


Anyways, if you're going to take anything away from this post, let it be the following two sentences:

You synchronized the clocks in the stationary frame.
How do you justify the assertion they are synchronized in the moving frame?

 

[geistkiesel]

Hurkyl is about to lunge onto his sword. Hurkyl is an honorable man.

We never get to talk about the results of your thought experiment becuase you continually deny SR in the setup of the experiment. You talk about things like instants of time, synchronized clocks, and simultaneous events, but in SR all of those things only have any meaning relative to some reference frame.


The primary way you've been misleading yourself with this thought experiment is the presence of multiple clocks per reference frame. Using your assumption that both sets of clocks will be synchronized, you are able to arrive at the conclusion you want.

See the posts between ram2048 and myself (#219 and 223). These were meant for your consumption also, amd anyone else interested. There is much for you to pick at. Some might call it "poetic"?

Np assumtions regarding synchronization at all. I made it abundantly clear that I was not synchronizing clocks between frames. I was synchronizing clocks within one frame, without reference tio the other frame. Do you have this clearly fixed in your mind?

If the stationary frame observers can assure themselves that their clocks are all calibrated to give the same time, then the same law of physics applied in the inertial moving frame also provides assurance that the clocks in that moving frame all tell the same time.

no clock sysnchrionization is conducted between frames. got it hurkyl?[/size]

The conclusion I want is the truth.

Furthermore, you have avoided doing any sort of other calculations with your experimental setup; one of the main points of this thought experiment is that if you don't use relativity, you must measure the speed of light to be something other than c.


I had to, more or less, trick you into doing one of these computations. You did a good job of computing a criterion for the moving observer to identify whether the photons were emitted simultaneously, so you're certainly capable of doing these sorts of calculations

The calculations are your job. I assume you will always get something consistent with SR. My job, only, is to demonstarte that the photons emitted at A and B simultaneously were also emitted simultaneously in the moving frame. I did this. I am still waiting for your honorable surrender, but that ain't going to happen will it?

Thank you for the compliment on my calculations. You recognize don't you, that my method was able to determine if the pulses were sent simultaneously from a moving frame to a stationary observer? And that under the conditions you set up, the photons were emitted simultaneously in the moving and and stationary frames and this is what I calculated. You do remember that do you not? You gave it all away Hurkyl, just now. you said basically, " good job".[/size]

I assume all the postulates that are used in SR. The constancy of the laws of physics and the constancy of the measured speed of light.

I wasn't stirring up dust, I was handing you rope.

Unfortunately, I was too impatient and opted to derive the final result myself instead of getting you to derive it, leading to the predictable result that you simply ignored the results without any sort of critical reasoning whatsoever. It seemed you felt the need to heap on some insults to rationalize this behavior, though, which I take as a good sign

You are telling me I had a close call, that I bit on your ruse, but your impatience was cause for my escape? Why would you hand me rope? I thought, LOL, we were in a science discussion, seeking he truth.

You wouldn't got me to do any more of your derivations. I was muttering to myself all along, as to why I was doing the calculations I was doing, this was your job. You fooled me big H.. Well as you said, I did get the right answer.

Hey, hurkyl, you just complimented me on my calculations where I contradicted your SR theory,you complimented me, remember?.

I give you the results contradicitng what you you derived, agreeing with what I derived and which you complimented me on.. You used SR and you got the expected SR results didn't you? Good, Now we have an unmabiguous meeting ground. I discoverd experimental proof that the photons were emitted simultaneously (your 'synchronization concerns satisfied as the same laws of physics and speed of light in inertial frames are invariant) in both frames, got it? Experimental results vs theory: The contradiction to be resolved by? Answer:Experimental results.

I do find it peculiar that you have been writing the last couple of pages as if you have actually performed an actual, physical experiment.

Well I did the same experiment that Einstein did, that is what this thread is all about, remember? Postulations, or mind rules, use of physical laws, are what we are talking about. How many times did Einstein go into a physics lab and tweak knobs and record ammeters and the such? I have never heard him doing this. It has been my personal experiience that when approaching any thing vaguely appearaing like a science lab, I hear glass breaking. I go not where the clues direct me elsewhere. But I did approach the labs. How about you H, are you a bigtime experimentalist?

Anyways, if you're going to take anything away from this post, let it be the following two sentences:

You synchronized the clocks in the stationary frame.
How do you justify the assertion they are synchronized in the moving frame?

I synchronized,calibrated is a better word, the clocks again in the moving frame using the same laws of physics and the constancy of the speed of light used in the stationary frame[/size]

This is your current coda? I am supposed to be breathless, awestruck and humbled aren't I? taking these two sentences away? OK, if you say so. You're the mentor.

 

[Hurkyl]

Np assumtions regarding synchronization at all. I made it abundantly clear that I was not synchronizing clocks between frames. I was synchronizing clocks within one frame, without reference tio the other frame. Do you have this clearly fixed in your mind?

If the stationary frame observers can assure themselves that their clocks are all calibrated to give the same time, then the same law of physics applied in the inertial moving frame also provides assurance that the clocks in that moving frame all tell the same time.

And how did that work again? Oh yes, it went something like:

A and A' are both set to 0 when they meet
M and M' are both set to 0 when they meet
B and B' are both set to 0 when they meet

In the stationary frame, since A, M, and B are all set to zero simultaneously, they must tell the same time afterwards. Also, in the stationary frame, A', M', and B' are set to zero simultaneously, so they must tell the same time afterwards.


However, you've given no justification for your assertion that they all meet simultaneously in the moving frame. In fact, it is a fairly trivial fact of Minowski geometry (the geometry used in SR) that two events are simultaneous in all frames if and only if they are at the same place at the same time; i.e. if they're the same event.

The conclusion I want is the truth.

Where "truth" is defined as whatever you believe?

The calculations are your job.

We've done a few. You don't listen. They must not satisfy your definition of "truth".

My job, only, is to demonstarte that the photons emitted at A and B simultaneously were also emitted simultaneously in the moving frame.

You're missing a crucially important part of your "job". If your goal is to prove Special Relativity is logically inconsistent, you must make this demonstration within the confines of Special Relativity. If you merely wish to show that Special Relativity doesn't reflect reality, then you must make this demonstration with an actual experiment, not a thought experiment.

You recognize don't you, that my method was able to determine if the pulses were sent simultaneously from a moving frame to a stationary observer?

I think I agree with the spirit of this statement. The pulses, though, weren't sent from a "moving frame"; they were sent from (moving) light sources.

And that under the conditions you set up, the photons were emitted simultaneously in the moving and and stationary frames and this is what I calculated.

I do not recognize this, because it is not true. I did the calculations comparing the two frames and showed precisely the opposite; they were simultaneous in one frame and not on the other. You, however, have not done the calculations for both frames under the conditions I set up.

I assume all the postulates that are used in SR. The constancy of the laws of physics and the constancy of the measured speed of light.

And you also assume a few more which are not made by SR.

Why would you hand me rope? I thought, LOL, we were in a science discussion, seeking he truth.

Why would I kick up dust? Or shovel out dirt? You're the one who wanted to bring up colorful analogies, I was just supplying one that is more apt.

How many times did Einstein go into a physics lab and tweak knobs and record ammeters and the such?

He did do more than just invent Special & General Relativity, you know.

are you a bigtime experimentalist?

Nope, I'm not a mathematician. And I'm certainly not the one going around implying that I have done this experiment.

I synchronized,calibrated is a better word, the clocks again in the moving frame using the same laws of physics and the constancy of the speed of light used in the stationary frame

Saying it does not make it so.

This is your current coda? I am supposed to be breathless, awestruck and humbled aren't I? taking these two sentences away? OK, if you say so. You're the mentor.

You can be breathless, awestruck, and humbled if you like. I merely wanted to make it crystal clear that this is where my primary objection to your analysis lies; it is more or less pointless to speak about anything else unless it is going to relate directly to this objection.

 

[ram2048]

it seems to me this is how things have been going for quite a while.

Geist defines a setup as such and asks Hurkyl to resolve it using SR
Hurkyl says that setup is no good for SR, how about THIS one
Geist says no that one doesn't work for me how about THIS one...

etc etc.

if you guys would agree on working with one setup you could probably resolve this quite efficiently... :D

 

[geistkiesel]

comiong to gether with defonitions.

it seems to me this is how things have been going for quite a while.

Geist defines a setup as such and asks Hurkyl to resolve it using SR
Hurkyl says that setup is no good for SR, how about THIS one
Geist says no that one doesn't work for me how about THIS one...

etc etc.

if you guys would agree on working with one setup you could probably resolve this quite efficiently... :D

I agree. I will confine myself to Einsteins gedunken of the train. M is the midpoint between two light sources at A and B. M' the midpoint of A' and B' on a moving inertial frtame, where A' = A and B' = B and M' =M when two photons are emitted from A and B. along the line of the moving platform moving toward B. The photon from B reaches M' before the photon from A.

The colocation of A = A', B = B" and M = M" is determoned from calulations of the shrinking of the moving frame consistent with the known velocity of the moving frame, say v = 1. AS the photons are emitted, the clocks at all are marked and stored in a data base. The clock at B' read the same as the clock at A', similarly the clock at A reads the same as the clock at B. These calibrations are accomplished by the same laws of physics that apply invariantly to both. There is no pretense to correlate the clocks in the two frames, other than to note the times of the emitted photons are stored in the stationary frame's computer for the stationary data. The time data are stored in the moving frame's computer for the moving frame data, the times recorded when all the coordinates were colocated as described.

It is my position that "simultaneity of the emitted photons" is defined at that instant in time when the photons were actually emitted into the universe. Under the conditions described here the photons were emitted simultaneously in both inertial frames.[/size]

It is my position that challenges to the claim here that the indicated readings of the clocks in the moving frame are not verifiable is not valid.. The clocks in the moving frame are calibrated with the same laws of physics used in the stationary frame used to calibrate clock there.

So are claims that A = A' and B = B' and M = M' cannot be achieved. Using SR theory we can calculate shrinkage and time dilation consistent with a known and repeatable velocty v = 1. These two measurments are only provided to guarantee he emission of thephoyons into the universe simultaneously.

There is no measurement of any passage of time by these clocks that are used in any calculation. The clocks are inserted and are used for the singular purpose of marking the simiultaneous nature of the emitted photons. The only exceoption is that the clock at M' is used to measure the arrival times of pulses from B then A ariving at M' where these times are referenced to the location of M' colocated with M when the photons were emitted.

From this I say my link has proved the simultabeous nature of he emitted photons. Likewise, Hurkyl has admitted that a calculation I made if a hypothetical he presented was calulated properly by myself and that I predicted the photons were emitted positively simultaneously. SR would have predicted otherwise, which escaped Hurkyl. he complimented me on my calulation.

 

[ram2048]

i want pictures of trains.

all this A B M and A' B' M' means little to me. what is that two trains?

 

[geistkiesel]

it seems to me this is how things have been going for quite a while.

Geist defines a setup as such and asks Hurkyl to resolve it using SR
Hurkyl says that setup is no good for SR, how about THIS one
Geist says no that one doesn't work for me how about THIS one...

etc etc.

if you guys would agree on working with one setup you could probably resolve this quite efficiently... :D

I just took short drive on some personal business and came up with a compromise measuring device. Along the length of the moving platform is a long cylindrical rod. Along the rod are embedded semiconductor high impedence photo-diodes. The distance between centers of the diodes are the state of the art minimum based on todays commercial art. [I think photo-lithograhic exposures are in the x-ray, or near x-ray range for device geometry definitions. but whatever the stae of the art comeical minimum is].

Each device is marked only by a number that defines its location along the rod. We start at M' = 0 and count + and minus up to and passed a fail safe distance insuring that all diodes will be provided over the disnce A to B in the stationary frame. The distance of x to M distance units in the positive direction is equal to the distance x distance units in the minus direction. tThe Number 10 stimulated device in the positive direction is equal tio the number 10 in the negative direction. All we will measure is the number of the device at the location of the the emitted photon at the loction of A and B when the photon is emitted. Period.

All distances measured along the rod in the moving inertial frame are equivalent if photons move equal distances in equal times along any segment of the rod in the moving frame.

As I see the experiment it is exactly like Einsteins except for the presence of the measuring rod in the moving frame. One of the devices is guaranteed to be colocated to a distance less than the wave length of the emitted photon. Many more devices are so colocated such that the resolution of measurement of the photon is much finer than a mere photon wave length resoluiton.

Bottom line: M', A' and B' are defined by a lest one device location along the measuing rod when the photons are emitted from A and B. The photons detected by the observer at M' first from B then A can be defiend by Hurkyl consistent with the laws of physics. He hasn't made any reference to the nature of these measurements so far so what ever resolution Hurkyl desires shall be my desire also.

The given is that M = M' when the photons are emitted in the stationary frame.

No clocks, no sending mesages to M or M'. no computer data base, calibration, synchronization, no frame-to-frame information exchange. We just keep within the experimental limits of Einstein's gedunken as described on pages 25 - 27 of AE's book "Relativity". No measuring rod information to be used in any calculations, as in the original gedunken. The information from the mesuring rods is extrinsic to all determinations of physical fact as in the original gedunken.

 

[geistkiesel]

Hurkyl, ram2048 had an observation that you and I were jumping all over the place with our experimental conditions. I posted a compromise I hope yu will find agreeable.(Two posts) I also suggest that both of us refrain from even the most subtle of personal dissing, OK? Let us be 100% successful in conducting our discussions purely on the issue of whether or not the emitted photons were emitted simultaneously in both frames. I am going to use Einsteins gedunken described in "Relativity" pages 25-27 with a slight modification for the taking of two data points. (See Post to ram2048) From past discussions All objections previously raised by yourself are satisfied.

 

[Hurkyl]

Shall I assume this discussion is to continue in https://www.physicsforums.com/showthread.php?t=29822 ?

Incidentally, I opened up "On the Electrodynamics of Moving Bodies" today, and it has Einstein's definition of synchronized clocks:


(He seems to implicitly assume the clocks are moving inertially; no acceleration)

Suppose we emit a photon from clock A and it reflects off of clock B and is observed back at clock A. Let tA be the time on A that the photon was emitted, tB be the time on B that the photon was reflected, and t'A be the time on A when the photon was observed again.

Then, the clocks are synchronized iff t'A - tB = tB - tA.

Once this definition is made, two events are simultaneous (relative to a collection of synchronized clocks... aka an inertial frame of reference) iff they occur at two of these clocks, and the clocks read the same time.

 

[geistkiesel]

Shall I assume this discussion is to continue in https://www.physicsforums.com/showthread.php?t=29822 ?

Incidentally, I opened up "On the Electrodynamics of Moving Bodies" today, and it has Einstein's definition of synchronized clocks:


(He seems to implicitly assume the clocks are moving inertially; no acceleration)

Suppose we emit a photon from clock A and it reflects off of clock B and is observed back at clock A. Let tA be the time on A that the photon was emitted, tB be the time on B that the photon was reflected, and t'A be the time on A when the photon was observed again.

Then, the clocks are synchronized iff t'A - tB = tB - tA.

Once this definition is made, two events are simultaneous (relative to a collection of synchronized clocks... aka an inertial frame of reference) iff they occur at two of these clocks, and the clocks read the same time.

In the first post of th thread "SR Simultaneous Lines Drawn in the Sand" the moving observer at M' was at M the midpoint of sources of photons in the stationary frame when the photons were emitted simultaneously. These photons were instantaneously detected in the moving frame as they were emitted in the stationary frame. The moving frame detected the simultaneous emission of the photons in the moving frame.
What do cklocks have to do with SR?

Along come Hurkyl and does what? He attempts to alter the direction of the current thread.
Hey, H start another thread.

 

[geistkiesel]

Shall I assume this discussion is to continue in https://www.physicsforums.com/showthread.php?t=29822 ?

Incidentally, I opened up "On the Electrodynamics of Moving Bodies" today, and it has Einstein's definition of synchronized clocks:


(He seems to implicitly assume the clocks are moving inertially; no acceleration)

Suppose we emit a photon from clock A and it reflects off of clock B and is observed back at clock A. Let tA be the time on A that the photon was emitted, tB be the time on B that the photon was reflected, and t'A be the time on A when the photon was observed again.

Then, the clocks are synchronized iff t'A - tB = tB - tA.

Once this definition is made, two events are simultaneous (relative to a collection of synchronized clocks... aka an inertial frame of reference) iff they occur at two of these clocks, and the clocks read the same time.

I have no quarrel with AE and his definition, but is the thjread that you wee responding to directly or indirectly on the issue? The AE train hypothetical has the moving frame receiving the photons from the forwad emitter then from the rear emitter. Is this dt at all significant in testing whether the photons were emiitted in the moving frame simultaneously with the emitted photons in the stationary frame?

Ii don't see the connection of this post to the train hypo. It seems that simultneity iis being artificially defined by the synchronization process and is fa removed from any physical pocesses.

If I missed something can you show me how SR comes to the conclusion that simltaneitymust be catagorically discarded in the train hypo? If i have not been clea befoe, this sold remove any ambiguity: The photons emitted from the two sources is a simultaneous event in he sationry frame. Eventually these photons arrive at the location of the moving frame. The descriptions presented to me say that the emssion of the photons at A and B were not emitted simultaneously in the movinmg frame. Why, or upon what rational is 'simultyabeity' referred back in time, to another frame, and then projected forward such that the current observers on moving frame [who may as well have not been born at the instant the photons were released] determine the photons weren't emitted simultaneously?

Is this a case of arbitrary definition? My hypothetical measurement experiment where the emitted photons are detected by photosensitive devices placed at the exact location of the emitting source in both frames should be consistent with any measuement scheme in the moving frame mesuring arrival times of the photons if SR theory is consistently applicable. Do you agree (technical measuing problems being irrelevant to the theoretical iscussion)?
negative answer imlies, to me, that SR becomes pureley observer determinate. I mean that it is the defined state of the observer, his perceptions, we are focused on as opposed to the physical event that defines simultaneity. If so what does SR and simulaneity have to do with physical events in describing those events after they occur in such a way that the actual event itself remains "absolutely" invariant, physically induistinguishable from theevent, under any real or implied activtivity conceivable ocuring after the fact of the event?

 

[ram2048]

wait...

according to the other thread light will always be measured at light speed relative to the observer...

so if the front one is coming at him at light speed and the back one is also coming at him at light speed...

oh... i see now why you're arguing :D

 

[geistkiesel]

wait...

according to the other thread light will always be measured at light speed relative to the observer...

so if the front one is coming at him at light speed and the back one is also coming at him at light speed...

oh... i see now why you're arguing :D

SR as seen through the lens of simultaneity is becoming to be grounded in a simple fact: The simultaneity phenomena is not descriptive of physical phenmomena, it is descripive of what a moving observer perceives as a correction for observing the different arrival times of the photons in the moving framew. This occurs, the correction, from failure to consider other options for the staggered arrival times of the photons, i.e. the most obvious, the moving frame is heading to the source of one oncoming photon and away from the source of the other catching up photon.

 

[ram2048]

certainly coming to the conclusion that the mover is actually moving is the smart way to look at things.