Has ayone seen the lost simultaneity?

In summary, the figure is of a moving frame that is moving to the right at velocity = 1/3c. On each end of the frame is a mirror located at 4(1/3 + 1/3 + 1/3 + 1/3) x (1 second) from the midpoint of the frame. A pulse of light emitted at M (on either the moving or stationary frame) is detected. We define the stationary point M when the pulse is emitted.
  • #71
Doc Al said:
Add that to your pile of mistaken beliefs.

Not sure what you are talking about. For low speeds you can certainly use Galilean addition of velocities. But realize it's only an approximation. (An incredibly good one, for NASCAR speeds!)

Doc Al said:
Also: You often talk about things "entering the moving frame". Bad habit. Things just are. They can be viewed from many different frames at once. They don't belong to one frame or another, but to all frames.

We have been talking about photons emitted simukltabeously in the stationary frame being simultaneously emitted in the moving frame. What are you talking about. I think you have some bad habit neediong correciton here not me.

Doc Al said:
I know you don't agree with it, but I'm still awaiting proof that you understand it.

What do you have that makes you feel that I owe you some proof that i undertsand SR? I undertstand it and you know I do,. iIjust believe it is garbage, that's all.

Doc al said:
When you make a post or reply to one you'll see a tool called "attach files". Just put your diagram in one of the acceptable file types and go for it. Let me know if it doesn't work for you.

Thanx for the "attachment" info.

Doc Al you and I both know that the gedunken we have been working on here does not use any SR postulates requiring time dilation, mass shrinking or any of the other SR inferences. Einstein's gedunken and the example given here is all he used. Einstein will have us believe because the oncoming photon was measured before the one approaching from the rear that this is suffciient to discard the simultaneity of events and to discard absolte time. read the reference you gave me, This is the same book I have been quoting from which you ridicule with your school yard jimmer jammer. Don't be dishonest DOc Al, There is only one life you have to live, don't let it be a lie that is as grossly uttered as SR.
 
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  • #72
Clearing up AE Gedanken ambiguities.

Einstein gedunken experiment has been much misinterpreted in this thread. This discussion is intended to clear up any misconceptions.

For those following this thread you can see the intensity of those defending the concept of simultaneity, for if simultaneity goes, so goes SR, out the window. Doc Al has made a valiant but fruitless effort to insert time dilation and mass shrinking into this discussion of AE’s gedunken, primarily by Doc Al.

Read and be your own judge.
Code:
_->                 M                   <-_.
A|__________________|____________________|B.
_a__________________O’___________________b__.
This is where we start. The moving observer O’ is at M the midpoint of A and B photon sources when photons are emitted. Passengers designated a and b detect these photons when first emitted. The train extends beyond the two A and B source locations.

As the train moves to the right, second line, there are four significant events to consider.

1. The photons are emitted simultaneously in the embankment observed by passengers a and b sitting adjacent to the A and B sources when the photons were emitted- call this time1
2 The observer O’ detects the on coming B photon - time 2.
3 The photons A and B arrive simultaneously at M in the stationary frame and are observed simultaneously by passengers sitting in those adjacent seats in the moving frame. We call these passengers a|b - time 3. These are not the same a and b passengers observing the original omission of the photons.
4 O’ observes the photon A from the rear – time 4.

Doc Al will scream that I haven’t said which frame we are counting time. I am using the same time frame Einstein used in his gedunken.

By this time all passengers sitting to the rear of O’ have detected the A and B photon, including the passengers sitting adjacent from M when the photons arrived at M in he stationary frame and observed simultaneoulsy in the moving frame by a|b pasengers simultaneously. simultaneously. simultaneously.

a. In describing this experiment Einstein did not invoke any aspects of special relativity certainly not time dilation or mass shrinking in the set-up of the experiment, or the conduct of the experiment.
b. AE drew all of his conclusions from this experiment based on the sequential arrival of the A and B photons at O’.
c. AE states that “Now in reality (considered with reference to the railway embankment) he [O’] is hastening toward the beam of light from coming from B, whilst he is riding on ahead of the light emitted from A. Hence the observer [O’] will see the beam from of light emitted from B earlier than he will that emitted from A.
d. When AE stated that the, ”Observers who take the railway train as their reference-body must, therefore come to the conclusion that the lightning flash B took place before lightning flash A. We thus arrive at the important result: Events, which are simultaneous with reference to the embankment, are not simultaneous with respect to the train, and vice versa (relativity of simultaneity). Every reference body (coordinate system) has its own particular time; unless we are told the reference body to which the statement of time refers, there is no meaning in a statement if the time of an event.” All of this in quotes follows from the sequential arrival and detection of the photons by O’ on the train, or so claims AE.
e. AE imposes the conclusions in B to all passengers on the train including those passengers that were located at the midpoint of the embankment when the photons arrived simultaneously there. Apparently AE has some special conditions associated with the mysterious O’ observer that do not attach to the other passengers on the train. Again, AE makes his conclusion based purely in the sequential detection of the A and B photons by O’. From this AE makes the conclusions stated in D above. This is essential and for those truly interested in following the discussion you should clarify the points to you satisfaction. There should not be any remaining ambiguity on the correct interpretation of the gendunken.

Now ask yourself: if there is one exception to a definition then does the definition fail?
In the world of physics and mathematics the answer is yes, the definition fails, or the conclusion is erroneous.

What Einstein actually found was that in the emission of photons into a moving frame at least one location on that moving frame will locate the simultaneous arrival of the emitted photons. What is simultaneous in a stationary platform is simultaneous in the moving platform.

What if the moving platform is only a grain of sand and is smaller than a fame extending to include the midpoint of the emitted photons in the stationary frame? One can calculate the spatial midpoint positions. It is not necessary to have a moving frame of the size and velocity that will always include the sources and midpoint s of the photons emitted.From time 4, or t4, we can calculate the correctness of whether the photons were emitted simultaneously in the moving frame as

T4 = T2(C + v)/(C – v)

where T4 is the time the A photon was detected and T2, the time the B photon was detected. As T2 and T4 are both measured, or detected values, the accuracy of the expression can be tested – if the calculation agrees with observation, the photons were emitted simultaneously. This would be a very simple experiment to conduct.

Further, the original observers of the emitted photons a and b, may compare their respective clocks later and determine the photons were emitted simultaneously in the moving frame and so on down the line of passengers from a ->, to the right as the A photons go past, and from <-b to the left as the B photons go past to the left.
 
  • #73
another swing, another miss

geistkiesel said:
Einstein gedunken experiment has been much misinterpreted in this thread.
By you.
This discussion is intended to clear up any misconceptions.
I assume you meant to say: "In this post I intend to repeat my misconceptions yet again."
For those following this thread you can see the intensity of those defending the concept of simultaneity, for if simultaneity goes, so goes SR, out the window. Doc Al has made a valiant but fruitless effort to insert time dilation and mass shrinking into this discussion of AE’s gedunken, primarily by Doc Al.
If you understood Einstein's simple argument with the train gedanken, you would know that nowhere does "time dilation" or "mass shrinking" :yuck: enter into it.
Read and be your own judge.
Code:
_->                 M                   <-_.
A|__________________|____________________|B.
_a__________________O’___________________b__.
This is where we start. The moving observer O’ is at M the midpoint of A and B photon sources when photons are emitted. Passengers designated a and b detect these photons when first emitted. The train extends beyond the two A and B source locations.
Your diagram implies that there are observers on the train (you call them a and b) who see those flashes happen at the same time. :rofl:
As the train moves to the right, second line, there are four significant events to consider.

1. The photons are emitted simultaneously in the embankment observed by passengers a and b sitting adjacent to the A and B sources when the photons were emitted- call this time1
By claiming that train occupants a and b observe the flashes at a single time, you merely assume what you intend to prove. You may as well stop right here.
 
  • #74
Proof of simultaneity of stationary/moving frame systems.

I have not read your replies. I just came up with another proof that the moving observer must conclude the photons were emitted in the moving frame simultaneously with the emitted photons in the stationary frame. All clocks on the moving frame are synchronized within the moving frame. The clocks in the vicinity of A and the clocks in the vicinity of B are showing the same time throughout the train at all times. When the photons are emitted at A and B they are then detected by a and b, which are clocks nearest to A and B in the moving frame. These clocks times are immediately relayed to O'. As these times are now electromagnetic radiation they will travel exactly as fast as the photons they just timed. Therefore the B photon arrival at O' is joined by the time the b clock in the moving frame detected the photon emission into the moving frame. Later the photon from A is also joined with the time stamp of the a clock, giving the time the A photon was emitted at A. O' then compares the a and b clocks and gets the same number in the moving frame clock system. O' must, therefore, come to the conlcusion the photons were emitted simultaneously in the moving frame. The timing information is also joined by the times the a|b observers detected the A and B photon arriving simultaneously at M.

That tap-tap-tap you hear in the background is just another SR Theory coffin nail being set, it's no big deal.
 
  • #75
If passengers A and B are on the train, the photons were emitted simultaneously in that frame and will meet at O' (who won't be in the center at the time).

In the stationary frame the left photon will be emitted first.
 
  • #76
Doc Al said:
Originally Posted by geistkiesel
Einstein gedunken experiment has been much misinterpreted in this thread.
By you.Quote:
This discussion is intended to clear up any misconceptions.


quote; Doc Al. I assume you meant to say: "In this post I intend to repeat my misconceptions yet again.

Quote geistkiesel:
For those following this thread you can see the intensity of those defending the concept of simultaneity, for if simultaneity goes, so goes SR, out the window. Doc Al has made a valiant but fruitless effort to insert time dilation and mass shrinking into this discussion of AE’s gedunken, [insidiously inserted by Doc Al.]


Doc Al said:
If you understood Einstein's simple argument with the train gedanken, you would know that nowhere does "time dilation" or "mass shrinking" enter into it

Why did you lie about this Doc?. You have been perverting my efforts from the get go. You haven't a clue what "mentor" means you creep.
Doc Al said:
Quote:Geistkiesel
Read and be your own judge.
Code:
_-> M <-_.
A|__________________|____________________|B.
_a__________________O’___________________b__.

Geistkiesel says:
This is where we start. The moving observer O’ is at M the midpoint of A and B photon sources when photons are emitted. Passengers designated a and b detect these photons when first emitted. The train extends beyond the two A and B source locations.

The a and b passenges seen at A and b detect the photons when they were emitted. a knows nothing of b and vice versa, except that they are cousins. They only determine the train clock time when the photons were emitted and these a and b passengers detected the photons.

Doc Al said:
Your diagram implies that there are observers on the train (you call them a and b) who see those flashes happen at the same time.

Not necessarily, because they are on opposite ends of the train. (See my proof in the following post). I merely say they record the time the photon was emitted at their respective stations. The gedunken tells us that the photons were emitted simultaneously in the stationary frame. Whether the a and b passenges are aware of this information is not given here. But if the photons were emitted simultanously in the stationary frame what conclusion do you come to when you see one of the photons emitted and you know your partner on the other end of the train is probably measuring the same thing you are measuring right? Right? Seems reasonable doesn't it?

In any event any errors are going to be swamped by the delta times between the B and A photon detetction by O'.
Doc Al said:
Quote:Geistkiesel
As the train moves to the right, second line, there are four significant events to consider.

1. The photons are emitted simultaneously in the embankment observed by passengers a and b sitting adjacent to the A and B sources when the photons were emitted- call this time1


By claiming that train occupants a and b observe the flashes at a single time, you merely assume what you intend to prove. You may as well stop right here.

Good catch. I meant only that 'a' detected the A photon when omitted. 'b' detetcted the B photon when emitted. By my adding the photons were emitted simultaneoulsy in the stationary frame merely repeats the experimental given. No conclusions are made at this time, but I sure would like to bet a lot of money on the outocme of any experiment.



Doc Al said:
By you.

I assume you meant to say: "In this post I intend to repeat my misconceptions yet again."

If you understood Einstein's simple argument with the train gedanken, you would know that nowhere does "time dilation" or "mass shrinking" :yuck: enter into it.

No Doc Al I meant in my post that you imposed these constrictions by making all your silly time is different to the moving and stationary observers. demands. You have been doing this consistently and you know it. You have been conniving, not too successfully, to interject confusion and smog into a seriously offered point of view, whether you agree with it or not.

So whatever you say,

Frankly, my Doc Al, I don't give a damn.


You just made a calculated dishonest move Doc Al. Tsk, tsk. Where are the scientific rules of integrity? Have you ever heard of them? i bet the rules are strictly relative, aren't they?

Doc Al said:
Your diagram implies that there are observers on the train (you call them a and b) who see those flashes happen at the same time. :rofl:

I say and after correcting myself above, that the a and b passengers detetcted the photons when emitted at A and B,. In other words their clocks recorded the time and then I add here, relayed the information immediately to O'.

:rofl: I also said that two different passengers a|b were adjacent to the A and B photons when the A and B photons arrived simultaneously at M the midpoint of the A and B photon sources. You would object if I claimed the a|b passengers (the train is 8 seats wide and the train is packed) detected the photons simultaneously with their arrival at M? :rofl: OK whatever you call the simultaneous arival of the A and B photon at the midpoint M when the a|b passengers, 8 of them, time stamped their observed arrival of the photons at M, the midpoint of A and B in the stationary frame. :rofl:

What did you think of the form and structure of the post Doc Al? Ease of reading? Information content? Persuasivenss of arguments?
 
  • #77
geistkiesel said:
I just came up with another proof that the moving observer must conclude the photons were emitted in the moving frame simultaneously with the emitted photons in the stationary frame.
Yeah, "another" one.

Let's cut through the nonsense, once again. Let's say a and b are the observers on the train located right next to the flashing lights at A and B when they flash. When the see the lights flash, they check the time. No need for any "relaying" of clock times anywhere. Assuming, like you did, that all clocks on the train are synchronized then--like it or not--observers a and b will record different times for the two photon emissions.
 
  • #78
geistkiesel said:
What did you think of the form and structure of the post Doc Al? Ease of reading? Information content? Persuasivenss of arguments?
Just the usual crap. You've said the same thing--including the obnoxious accusations of my "lying"--many, many times.
 
  • #79
Doc Al said:
Just the usual crap. You've said the same thing--including the obnoxious accusations of my "lying"--many, many times.

OK maybe one, or both of us had a mental lapse. I went out of my way to avoid using SR imperatives when makingh my calculations. I do remember you often criticzing me for using stationary times with moving frame times (which I denied doing).You use of the :rofl: was proficient.

If I err then I publically apologize. If it was a misinterpretation of what you were saying I was doing vs what I perceived you doing I will leave it at that. At least, at this time there is no ambiguity is there? I am now stating unequivacally that I reject the necessity of the use of any SR aspects or imperatives in determining the conclusions of AE's gedunken. If this isn't good enough to salve your obvious anger at the accusations then so be it. I can do no more.

Ok what usual crap. Spell it out. Everybody wants to know especially myself.

Did I make any improper claims of simultaneiity of events? I did make corrections, or clairifications, are you aware of these?

Is it not feasible that I can conclude that a moving frame has at least one point associated with a midpoint of photons emitted simultaneously from a stationary frame? Even if the midpoint falls off the frame, or cannot be determined from the information available.

You said the NASCAR example fell under the umbrella of SR. The low velocity makes it difficult to measure, but we are working theory here. What distinguihes NASCAR and the AE gedunken?

Do you agree that the difference in time that the O' observer measuresd the arrival of the B and A photon is the basis of AE concluding that the passengers "must , therefore conclude" the photons were not emitted simultaneously in the moving frame?

Did not the determination of the a|b passengers adjacent to the the midpoint when the A anad B photons arrived at M simultaneously fullfill the definition of the sources being separated equally at M and that the a|b passengers marking the time the photons arrived is a detection of simultaneously emitted photons in the stationary frame, at the very least? If so then what is it that prevents you from agreeing that the a|b passengers seeing the arrival of the A and B photons at M simultabeously is not a measurement of the photons simultaneously in the in the moving frame in the same sense that the O' observer could not so detect the photons simultaneously?

Do you agree that any SR constraints, if any, of the problem is swamped by the difference in time of measuring the B and A photons by the O' observer?

Fact assumed: the clocks of the a and b passengers located at A and B when the photons were emitted were synchronized wrt the moving frame. If the clocks later show the same time for the emission of the photons, does not this constitutes a detection of the the photons simultaneously such that the event of the simultaneously emitted photons in the stationary frame also constitutes simultaneously emitted photons in the moving frame as well? If no why not?

Under the given circumstances, could any of the passengers have ever detected or determined the emission of the A and B photons simultaneously into the moving frame? Why?

You seem to think I have not described a situation that is either proved, or provable, where is the error, so I don't crowd the forum with this pitifull junk? Shiow me I will stop this as sudeenly as I started it. Just prove it. Those watching can determine my "honesty" in this regard.

What usual crap are you referring? Be brief, or lengthy, just don't be ambiguous, ok?

I have concluded that we are at at an impasse. Like Robin Hood and Friar Tuck meeting in the middle of the stream joisting for the only dry passage over the stream to the other side. Where is the crap? Point to it directly, I implore you. In fact you owe it to yourself to be as clear with a physical description as you are able at least to the level of certaqinty you show by the level of your sarcastic quips, your use of :rofl:, and your anger and cycnicism.

Priove it Doc Al, or get another profession, bcause sooner or later someone just might ask you to do just that, prove it, I mean, like your boss.Or is she the one that directed you to stuff this line of reasoning where it would never see the light of day?

I know the rhetorical dangers of being painted into a corner and painting another into a corner [Huis Clos], but once the paint has been spread onto the floor, the dye is cast, n'cest pas? (pun intended)
 
  • #80
geistkiesel said:
Is it not feasible that I can conclude that a moving frame has at least one point associated with a midpoint of photons emitted simultaneously from a stationary frame? Even if the midpoint falls off the frame, or cannot be determined from the information available.
I have no idea what you are talking about. Here's a guess: Is there a point on the train that coincides with M at the moment that the light from A and B reaches M? Of course there is. So what?


You said the NASCAR example fell under the umbrella of SR. The low velocity makes it difficult to measure, but we are working theory here. What distinguihes NASCAR and the AE gedunken?
What are you talking about now? SR applies to EVERYTHING!
Do you agree that the difference in time that the O' observer measuresd the arrival of the B and A photon is the basis of AE concluding that the passengers "must , therefore conclude" the photons were not emitted simultaneously in the moving frame?
The fact (agreed to by ALL observers) that light from B hits O' before the light from A leads the O' frame to conclude that the lights did not flash simultaneously.

Did not the determination of the a|b passengers adjacent to the the midpoint when the A anad B photons arrived at M simultaneously fullfill the definition of the sources being separated equally at M and that the a|b passengers marking the time the photons arrived is a detection of simultaneously emitted photons in the stationary frame, at the very least? If so then what is it that prevents you from agreeing that the a|b passengers seeing the arrival of the A and B photons at M simultabeously is not a measurement of the photons simultaneously in the in the moving frame in the same sense that the O' observer could not so detect the photons simultaneously?
I have no idea what you're saying here. Get this straight: Observers a and b DO NOT detect the flashes simultaneously.

Do you agree that any SR constraints, if any, of the problem is swamped by the difference in time of measuring the B and A photons by the O' observer?
What's that supposed to mean?
Fact assumed: the clocks of the a and b passengers located at A and B when the photons were emitted were synchronized wrt the moving frame. If the clocks later show the same time for the emission of the photons, does not this constitutes a detection of the the photons simultaneously such that the event of the simultaneously emitted photons in the stationary frame also constitutes simultaneously emitted photons in the moving frame as well? If no why not?
If observers in O' measure two events to occur at the same time according to their clocks, then of course those events are considered simultaneous in the O' frame. That's what is meant by simultaneous.

Under the given circumstances, could any of the passengers have ever detected or determined the emission of the A and B photons simultaneously into the moving frame? Why?
No. See Einstein's Train Gedanken for a simple proof that events simultaneous in the O frame cannot be simultaneous in the O' frame. We've discussed this many times. Of course, you keep dodging that one. (Why do you insist on adding stuff to Einstein's simple argument?)

If you are REALLY interested, go back and read all the many, many posts in which I have painstakingly explained every inch of the "Einstein Train Gedanken" problem. Even better, pick up a relativity book.
 
  • #81
Quote:
Originally Posted by geistkiesel
I just came up with another proof that the moving observer must conclude the photons were emitted in the moving frame simultaneously with the emitted photons in the stationary frame.
Yeah, "another" one.

Doc Al said:
Let's cut through the nonsense, once again. Let's say a and b are the observers on the train located right next to the flashing lights at A and B when they flash. When the see the lights flash, they check the time. No need for any "relaying" of clock times anywhere. Assuming, like you did, that all clocks on the train are synchronized then--like it or not--observers a and b will record different times for the two photon emissions.

Based on what Doc? You are so emphatic. Based on what?

You have a problem here Doc Al. Let us assume that there is only one emitter say A, then can the a passenger located at A when A emits the photon accurately determine the time the A photon was emitted? Sure 'a' can do thisa slam dunk easy as pie task..

Now A and B are inanimate photon sources that emit photon simultaneously in the stationary frame right?, each "knowing absolutely nothing of the other source."?
Similarly for the a and b detectors that do not have to be people. Now if one detector can accurately determine the emission of a photon, how in hell can two photons be deteced sequentially? Ram1024 suggested god intervened. Is this what you SRists have done, recruited god to your side?If so then this isn't playing fair.

And how do the sources determine which photon gets to be emitted first. Do they check with someone before acting? Maybe its nonlocal activity? hmmmm?

In other words, how do the A and B photon sources know which is at which end of the train and, hence, which photon must be emitted before the other, in the moving frame that is? Is this one of those "that's just the way it is?"


Doc Al said:
I have no idea what you are talking about. Here's a guess: Is there a point on the train that coincides with M at the moment that the light from A and B reaches M? Of course there is. So what?

If the a|b passengers, those located at M when the photons arrived simultaneously, wouldn't this satisfy the definition of simultananeity when they see and record the simultaneous arrival of the photons? We are still in the Eisntein train gedunken and haven't resorted to SR imperatives as Einstein did not so resort in his discussion of the gedunken.



Doc Al said:
What are you talking about now? SR applies to EVERYTHING!

OK if SR applies to everything how does it apply to the measurement of the B and A photon sequentially? And how is this measurement related to SR, in light of the other simultaneous measurements I have discussed here, [that you disagree with of course]?.

Doc Al said:
The fact (agreed to by ALL observers) that light from B hits O' before the light from A leads the O' frame to conclude that the lights did not flash simultaneously.

Is the difference in the time the B and A photon were detected such as to swamp any SR effects that you alluded to where "SR applies to EVERYTHING!"? In other words can SR effects be calculated or measured in the Einstein gedunken?


Doc Al said:
Get this straight: Observers a and b DO NOT detect the flashes simultaneously.

I discussed this elsewhere, but are you saying that if there were only one photon emitter, say A, that the 'a' passenger could properly detect the time the A pohoton was emitted?

Doc L said:
If observers in O' measure two events to occur at the same time according to their clocks, then of course those events are considered simultaneous in the O' frame. That's what is meant by simultaneous.


No. See Einstein's Train Gedanken for a simple proof that events simultaneous in the O frame cannot be simultaneous in the O' frame. We've discussed this many times. Of course, you keep dodging that one. (Why do you insist on adding stuff to Einstein's simple argument?)


BECAUSE EINSTEINS ARGUMENT IS SPECIOUS, INCOMPLETE A CONTRIVANCE, INANE NOT IN ACCORD WITH OPHYSICAL LAW AND EXPERIMENTAL RESULTS.

Doc Al said:
]
If you are REALLY interested, go back and read all the many, many posts in which I have painstakingly explained every inch of the "Einstein Train Gedanken" problem. Even better, pick up a relativity book.

You haven't explained 1/16 of an inch to me. I have read a lot of posts like he one above that says: quote DOc Al "Get this straight: Observers a and b DO NOT detect the flashes simultaneously."
This statement proves nothing. It is just another SR mantra.


I read your link regarding Einstein's "Relativity" a treasured book I have been quoting from the get go. You even sneered at this once.
 
  • #82
Another subject. If I vow not to post on any but Theory Development can my privileges regarding other forum activities be reatored? Access to my profile, private messages etc. One violation 86 me, OK?
 
  • #83
geistkiesel said:
Quote:
You haven't explained 1/16 of an inch to me. I have read a lot of posts like he one above that says: quote DOc Al "Get this straight: Observers a and b DO NOT detect the flashes simultaneously."
This statement proves nothing. It is just another SR mantra.

Awww, too bad you repeating something doesn't make it true either. I also like how you said SR goes against experimental results. BS at its finest.
 
  • #84
Even though I keep telling myself to stop wasting time, I just can't resist. You are too funny, geistkiesel!

geistkiesel said:
You have a problem here Doc Al. Let us assume that there is only one emitter say A, then can the a passenger located at A when A emits the photon accurately determine the time the A photon was emitted? Sure 'a' can do thisa slam dunk easy as pie task..
Let's be clear. Light A flashes. At that very instant, observer "a" on the train is directly opposite point A. Observer "a" detects the flash and records the time. Where's the problem?
Now A and B are inanimate photon sources that emit photon simultaneously in the stationary frame right?, each "knowing absolutely nothing of the other source."?
So far, so good.
Similarly for the a and b detectors that do not have to be people. Now if one detector can accurately determine the emission of a photon, how in hell can two photons be deteced sequentially?
Uh... because one was detected before the other? :rofl:
And how do the sources determine which photon gets to be emitted first. Do they check with someone before acting? Maybe its nonlocal activity? hmmmm?
Their time of emission is determined by clocks in the O frame. No mysterious nonlocal forces between photons.
In other words, how do the A and B photon sources know which is at which end of the train and, hence, which photon must be emitted before the other, in the moving frame that is? Is this one of those "that's just the way it is?"
The photons know nothing. They just flash when triggered to do so. It's kind of trivial.
If the a|b passengers, those located at M when the photons arrived simultaneously, wouldn't this satisfy the definition of simultananeity when they see and record the simultaneous arrival of the photons?
All measurements made in the O' frame agree with the fact that the flashes were not simultaneous in the O' frame.
We are still in the Eisntein train gedunken and haven't resorted to SR imperatives as Einstein did not so resort in his discussion of the gedunken.
Einstein invokes the invariant speed of light: and from that deduces all of SR.
OK if SR applies to everything how does it apply to the measurement of the B and A photon sequentially? And how is this measurement related to SR, in light of the other simultaneous measurements I have discussed here, [that you disagree with of course]?.
Your "other simultaneous measurements" are just things you made up. But, looking at things from the O frame it's trivial to show that M' detects a photon from B before detecting a photon from A. After all, M' is moving towards B and the light (which travels at speed c with respect to O) is moving towards M'. This staggered arrival of photons at M' is a real physical effect that everyone will agree upon. The O' frame can use this information to deduce (from the invariant speed of light as viewed from the O' frame) that the lights could not have flashed simultaneously at the moment M' passed M according to the O' clocks. (Damn, I must have explained this trivia about 1000 times by now.)
Is the difference in the time the B and A photon were detected such as to swamp any SR effects that you alluded to where "SR applies to EVERYTHING!"? In other words can SR effects be calculated or measured in the Einstein gedunken?
Don't know what you are talking about. What "swamps" SR effects? The entire discussion of the train gedanken is an "SR effect"!

Can the train gedanken be used to illustrate all the SR effects? Of course! But for that you'd have to know some relativity. (For example: Tell me how far is "a" from M'? How far is "a" from M at the moment that A flashes? What time does the "a" clock read when A flashes? etc, etc.)
I discussed this elsewhere, but are you saying that if there were only one photon emitter, say A, that the 'a' passenger could properly detect the time the A pohoton was emitted?
The "a" observer could detect the time that the A light flashed according to the O'-synchronized clock that he uses. Why is this so difficult for you?
BECAUSE EINSTEINS ARGUMENT IS SPECIOUS, INCOMPLETE A CONTRIVANCE, INANE NOT IN ACCORD WITH OPHYSICAL LAW AND EXPERIMENTAL RESULTS.
A laughable comment. (1) SR is in complete--and overwhelming--accord with experiment, (2) you know nothing of physical law, and (3) why do you keep quoting Einstein if you don't agree with his simple (HS level) argument? I'm still waiting for you to point out the flaw in it. (And without your usual smoke screen of mirrors and extra observers.)
I read your link regarding Einstein's "Relativity" a treasured book I have been quoting from the get go. You even sneered at this once.
This "treasured book" remains a mystery to you. And I wasn't sneering at the book. :smile:
 
  • #85
Even though I keep telling myself to stop wasting time, I just can't resist. You are too funny, geistkiesel!
Quote:
Originally Posted by geistkiesel
You have a problem here Doc Al. Let us assume that there is only one emitter say A, then can the a passenger located at A when A emits the photon accurately determine the time the A photon was emitted? Sure 'a' can do thisa slam dunk easy as pie task..
Doc Al said:
Let's be clear. Light A flashes. At that very instant, observer "a" on the train is directly opposite point A. Observer "a" detects the flash and records the time. Where's the problem?

I asked the question using A and a. Now ask the same question using B andb and I get the same answer, via a symmetry argument OK? You cannot say otherwise.
If a and b, separately can record the time of the photons where and when emitted in the moving frame separately, when emitted in the stationary frame, why cannot they do so when the a and b observers are both observing the A and B flashes that flash simultaneously?
 
  • #86
Alkatran said:
Awww, too bad you repeating something doesn't make it true either. I also like how you said SR goes against experimental results. BS at its finest.
For now we settle for a gedunken experiment. observer 'a' in the moving frame is adjacent to A the source of A photons in the stationary frame just as A emits the photon. Does 'a' in the moving frame detect the photon when emitted? assuming the 'a' detetcor is one wavelength from the emitting source A?
 
  • #87
If O' detects the A and B photons simultaneously in her frame she therefore concludes the photons were emitted simultaneously in the moving frame. Now she must conclude the photons were not emitted simultaneously in the stationary frame, right?
 
  • #88
O' considers herself stationary and watches the station move past her to the left. Just as M in the moving station is adjacent to O' photons are emitted simultaneously in the moving station frame. These photons when emitted were equidistant from M and hence equidistant from O' when emitted. Hence, O', knowing the speed of light is constant in her stationary frame will absolutely be guaranteed that the photons from the A and B emitters have the exact distance to travel form A and B in order to reach her. Hence the photons will spend the same time of flight in reaching her stationary position, hence the photons will arrive at her position simultaneously. Light is constant for the A and B photon when measured from O' frame, no problem correct?
 
  • #89
The moving frame with O' is at M when photons are emitted simultaneously from A' and B' sources where O' is the midpoint of the A' and B' sources. A' and B' will arrive simultaneously at M in the stationary frame as the speed of light is invariant in the stationary frame.. However, as the light is still invariant to O' she is still going to collide with the B' photon earlier than she detects the A' photon for the same reasons she did so when the sources were in the stationary frame.

Hence, what is simultaneous in the moving frame is simultaneous in the stationary frame, hence a violation of the relativity of simultaneity.

And the real joker here is that what is simultaneous in the moving and stationary frames, the emission of the A' anad B' photons, will be determined by O' not to be simultaneous at her position when she detects the staggered arrival of the B' and A' photons.
 
  • #90
O' considers her frame as stationary when the train station rushes by. A' and B' photons are emitted simultaneously in her considered stationary frame just as O' is at M in the train station frame rushing by. The A' and B' photons arrive simultaneously at M. O' is considering that the photons B' and A' must reach her simultaneously as she has considered herself stationary. However, phyisics doesn't cooperate. The photons arrive simultaneously at M in the train station considered by O' to be moving as light speed is invariant under motion of the source. O', considering herself stationary will be waiting patiently for the simultaneous arrival of the B' and A' photons. When the B' photons arrives first, she becomes confused, and starts to blabber SR mantras in a vain attempt to correct what she knows to be wrong, physically wrong. The photons have to arrive at her position simultaneously because, dammit, she considered herself stationary, Doc Al told her she could do that. However, as the light speed is still invariant to O' she is still going to collide with the B' photon earlier than she detects the A' photon for the same reasons she did so when the sources were in the stationary frame, the reasons being the laws of physics makes her considerations of her stationary frame silly and I might add, impossible.

When you are moving, you have to keep up the speed or else you auger in if considering yourself stationary. This is what is known in SR theory as the SR stall speed.

Another point to broadcast is that in all these cases the realtive velocity of the observers and photons is crucial to determining and predicting the correct outcome of the events.

Hence, what is simultaneous in the moving frame is simultaneous in the stationary frame, hence a violation of the relativity of simultaneity.

And the real joker here is that what is simultaneous in the moving and stationary frames, the emission of the A' anad B' photons, will be determined by O' not to be simultaneous at her position when she detects the staggered arrival of the B' and A' photons, even if she considerd herself stationary, damn, damn, damn.

So we have a return to absolute speed, zero in this case, also absolute time, I might add.
 
  • #91
Doc Al, Take a look at my last post in "No postulate of light violated in galilean trasnformation". It is in regard to my famous "sneer" t3 = t1(C + V)/ (C - V) expression. You might be interested. I addressed the post to tom_mattson, as that is what I was working on when I came across something in the intenet. take a look. No bull **** on this one.
 
  • #92
geistkiesel said:
Doc Al, Take a look at my last post in "No postulate of light violated in galilean trasnformation". It is in regard to my famous "sneer" t3 = t1(C + V)/ (C - V) expression. You might be interested. I addressed the post to tom_mattson, as that is what I was working on when I came across something in the intenet. take a look. No bull **** on this one.
Take a look at my response, where I explain once again how that trivial expression is derived and what it means. Take notes this time.
 
  • #93
geistkiesel said:
O' considers her frame as stationary when the train station rushes by. A' and B' photons are emitted simultaneously in her considered stationary frame just as O' is at M in the train station frame rushing by. The A' and B' photons arrive simultaneously at M. O' is considering that the photons B' and A' must reach her simultaneously as she has considered herself stationary. However, phyisics doesn't cooperate. The photons arrive simultaneously at M in the train station considered by O' to be moving as light speed is invariant under motion of the source. O', considering herself stationary will be waiting patiently for the simultaneous arrival of the B' and A' photons. When the B' photons arrives first, she becomes confused, and starts to blabber SR mantras in a vain attempt to correct what she knows to be wrong, physically wrong. The photons have to arrive at her position simultaneously because, dammit, she considered herself stationary, Doc Al told her she could do that. However, as the light speed is still invariant to O' she is still going to collide with the B' photon earlier than she detects the A' photon for the same reasons she did so when the sources were in the stationary frame, the reasons being the laws of physics makes her considerations of her stationary frame silly and I might add, impossible.

When you are moving, you have to keep up the speed or else you auger in if considering yourself stationary. This is what is known in SR theory as the SR stall speed.

Another point to broadcast is that in all these cases the realtive velocity of the observers and photons is crucial to determining and predicting the correct outcome of the events.

Hence, what is simultaneous in the moving frame is simultaneous in the stationary frame, hence a violation of the relativity of simultaneity.

And the real joker here is that what is simultaneous in the moving and stationary frames, the emission of the A' anad B' photons, will be determined by O' not to be simultaneous at her position when she detects the staggered arrival of the B' and A' photons, even if she considerd herself stationary, damn, damn, damn.

So we have a return to absolute speed, zero in this case, also absolute time, I might add.


SR stall speed- that's funny. A very succinct and clear analysis I might add.
 
  • #94
Doc Al said:
Take a look at my response, where I explain once again how that trivial expression is derived and what it means. Take notes this time.
Doc will yopu please look at the link I referenced. My expression is used in a very sophisticated simultabneity analysis. Look at it godamnit!.
 
  • #95
geistkiesel said:
Doc will yopu please look at the link I referenced. My expression is used in a very sophisticated simultabneity analysis. Look at it godamnit!.
Do you really think that link which discusses relativity will support your anti-relativity crusade? :rofl: Yes, that kind of expression does come up. But it's not what you think it is. That article is way too advanced for you.

Why not try reading it from the beginning? You may learn something.
 
  • #96
Doc Al said:
Do you really think that link which discusses relativity will support your anti-relativity crusade? :rofl: Yes, that kind of expression does come up. But it's not what you think it is. That article is way too advanced for you.

Why not try reading it from the beginning? You may learn something.
How in the hell do you know what I think it is? I thought it was interesting dingdong. You are the one avoiding discussing the link. This makes me think I just found out what I have been thinking all along. I put you out of your league, didn't I? I do notice that when I write something decent, at least one line per post, that you avoid the difficult stuff, or you do your frame swapping routuine, or chortle, or start shouting i am using stationary times, or ...anything but physics, or, when you are up against the wall and they are tying the blindfold to cover your eyes, you bring out your most potent weapon, the: :rofl:
 
  • #97
Doc Al said:
Take a look at my response, where I explain once again how that trivial expression is derived and what it means. Take notes this time.
I know what it measn Doc.
 
  • #98
geistkiesel said:
I do notice that when I write something decent...
When did this happen?
 
  • #99
Doc Al said:
When did this happen?
We put the emitters in the moving frame and just as the sources A' and B' arrive at A and B in the stationary frame, the A' and B' sources emit photons. The O', who was at M in the stationary frame when the photons were emitted simultaneously in the moving frame still heads to the B' photon on a collision course and detects the B' photon first, then later the A' photon.


Therefore, the passengers on the railway train must, therefore, conlcude the photons emitted simultaneously in the moving frame, were not emitted simultaneously in the moving frame. Hence the passengers all come to the conclusion, simultaneously, that special relativity theory sucks.
 
  • #100
lights on the train? No problem!

geistkiesel said:
We put the emitters in the moving frame and just as the sources A' and B' arrive at A and B in the stationary frame, the A' and B' sources emit photons. The O', who was at M in the stationary frame when the photons were emitted simultaneously in the moving frame still heads to the B' photon on a collision course and detects the B' photon first, then later the A' photon.
I'm not sure what the set up is in this scenario, but the following is true. It doesn't matter if the emitters are on the train or on the embankment. If the embankment observes them flashing simultaneously, then the train will not. And vice versa.
 
  • #101
again, Doc Al is playing with the word "simultaneously".

we don't care what they OBSERVE simultaneously. we care what they CALCULATE as EMITTED simultaneously.

you know that's what we want and you dodge behind your relativity facade every chance you get :D
 
  • #102
ram1024 said:
again, Doc Al is playing with the word "simultaneously".
No I'm not.
we don't care what they OBSERVE simultaneously. we care what they CALCULATE as EMITTED simultaneously.
That's what I mean by "observe". This is fairly common usage in discussing relativity, but I agree I could be clearer. By "observe" I mean: calculate, measure, deduce, etc. When I say that one frame will "observe them flashing" I mean deduce the time of emission based upon measurements made in that that frame. Of course, if that frame happened to have an observer at the right place and time, they could directly "observe" the emission. But that's hardly necessary.
you know that's what we want and you dodge behind your relativity facade every chance you get :D
Nice try. Now go back and reread every post I've made with the proper understanding of "observe". :rofl:

If you were really paying attention, the meaning should be clear from context. That is if you had a clue what SR says. But I see your point.
 
Last edited:
  • #103
just trying to ruffle your feathers really <chuckle>
 
  • #104
Doc Al said:
I'm not sure what the set up is in this scenario, but the following is true. It doesn't matter if the emitters are on the train or on the embankment. If the embankment observes them flashing simultaneously, then the train will not. And vice versa.

This Einstein gedunken is different from Einstein's original experiment only that the photons are emitted from the moving frame at A' = A and B' = B when the moving obser O' is located at O' = M, where M is the midpoint of the A and B photon detectors (when used) and from data from 1000 previous experiments identical to this experimetn, the exact midpoint of A' and B' on the moving frame is located in the stationaray frame M''.
Here's the set up:
  1. I and others have claimed that special elativity is a perception of the observer game - it isn't a physical dynamic being imposed - it is purely in the minds of beholding observers, So, question #1. If the photons were emitted simultaneously in the moving frame and the moving frame observers detect the B' and A' phoptons sequentially with the same moving frame clock indications as wehen the photons had been emitted in the stationaray frame,, why do the mpoving frame observers still conclude the photons were not emitted simultaneously in the moving frame?
  2. The stationary frame has photon detectors at A = A' and B = B' and record the time the photons were emitted in the moving frame, say distrinuted in a density of 1000/photon-wavelength. Relative simultaneity demands that the stationary frame, even with its high number of photon detectors will not record the photons emitted from the moving platform as being simultaneously emitted into the stationary frame. Question#2: In the context of Einstein's gedunken, what measuring scheme will the stationary observer use to support the conclusion of relative simultaneity? Will they record the photons in a mirror image reflection of the case where the photons were emitted simultaneously in the stationary frame and the moving frame observer detected the photons sequentially,first at B then A?
  3. The A' and B' photons were emitted spatially at locations mirroring AE's original gedunken where the photons were emitted in the stationary frame. The observer on the moving frame will see the photons sequentially with the clocks synchronized wrt the moving frame.
    • The moving frame observer detects the B' and A' photons in the following order:
    • The photns at A' and B' simultaneously by a' and b' on the moving frame located at A' and B'.
    • By O' the B' photon arriving on a collision course with O'.
    • At the original midpoint of the moving frame when O' = M.
    • by O', A' arriving from behind.
    • By this time all passengers located between A' and B' when the photons were emitted have observed and clocked the A' and B' photon's arrival times at their locations.
    Question #3: Will the observers/passengers on the moving frame conclude the photons were emitted simultaneously in the moving frame?
  4. The photons in the moving frame are detected in the exact sequence the photons were detected when emitted simultaneously in the stationary frame. From the clocks of the a' and b' observers located at A' and B' in the moving frame the times of emission are exactly the same, identical, simultaneous.Question #4: Will the observers on the moving frame conclude the photons were emitted simultaneoulsy in the moving frame?
  5. Question #5:Under what conditions, if any, will observers on the moving frame be able to conclude photons are emitted simultaneously in the moving frame[/B]?
  6. The photons are detected in the same order they were detected when emitted in the stationary frame. Question #6:Explain the application of relative simultaneity in the context of this gedunken.
  7. This post says the moving observer's conclusions are dependent on what the stationary frame observers detect. Describe the the stationary observers photon detection process, in terms of a time history in this experiments if the stationary observers conclude:
    • the photons were not emitted in the stationary frame simultaneoulsy or,
    • the photons were emitted simultaneously.
There is no observable stationary frame. In isolated space the moving observer has no stationary observer to communicate with in order to know what the stationary observers concluded. The moving observer detectced the A' and B' photns (emitted in the moving frame) in the same sequence as when the photons were emitted by the stationary observer, when there was a stationary observer. Therefore, I conclude the response is incomplete as there being no frame/frame comparison possibility. Will the moving frame here conclude the photons were emitted simultaneously in the moving frame?
 
  • #105
geistkiesel said:
This Einstein gedunken is different from Einstein's original experiment only that the photons are emitted from the moving frame at A' = A and B' = B when the moving obser O' is located at O' = M, where M is the midpoint of the A and B photon detectors (when used) and from data from 1000 previous experiments identical to this experimetn, the exact midpoint of A' and B' on the moving frame is located in the stationaray frame M''.
Before we follow the yellow brick road to the land of Oz, let's define our terms. I assume you mean by A' and B' certain locations on the train. I further assume that these locations are the positions in the train that were directly opposite A and B when the lights flashed at A and B. Is that what you mean by A' and B'?

If so, then what is the set up? You now have lights at A' and B'? (These points happen to be equidistant from M'.) And they flash simultaneously according to who?

Note that if A' flashes when A' passes A, and B' flashes when B' passes B, then they obviously do not flash simultaneously in the train frame.
 

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