Today Special Relativity dies

[ram1024]

no DUH it's because of length contraction

but the length contraction is wholly based on the wrongness of the picture. Length contraction, Time Dialation, constant light speed are COMPLETELY based off of using the wrong picture to measure distances and times.

look at case2 which is the RIGHT way to measure things. that is the way we measure EVERYTHING else in the universe. why measure light different?

because you're all a bunch of lunatics :D

 

[Alkatran]

Because all measurements of light have shown that that is the only way to measure it. Duh.

You see, it's all math until you apply it to REALITY, that's when it becomes Physics.

 

[ram1024]

no, you could measure it THE CORRECT WAY

craziness.

i'm going to have to make machines to do it properly aren't i. dammitall

 

[Alkatran]

Oh, you're so willing to learn, aren't you? The mere idea that time can be so lined with space drives you mad.

You go and make your machines to measure c, but there's no point, people much more intelligent than you have tried it before. Guess what? They all found out the same thing (except maybe the ones who made mistakes): Einstein was right.

 

[ram1024]

no einstein assumed that the motion of the observer makes no difference which is a ludicrous proposition AT BEST.

all calculation done for speed of light were taken WITH a stationary observer completely discarding that motion/distance

time/space is fine, but not with light as absolute speed defining it.

 

[Eyesaw]

Quote:
Originally Posted by Eyesaw
Actually my suggestion is that you try running from the burn marks on the track until you catch up to the observer inside the train and then tell us if there is a difference between running just from the burn marks on the train to the middle of the train.

I don't understand your point. What kind of difference? Elaborate please..
Quote:
Originally Posted by Eyesaw

Because if a frog and a duck were on the track at the time and place of simultaneous lightning flashes A&B (according to the embankment observer *snort*) , they would both be fried, despite what the train observer using SR's wrong assumptions calculate.

Yes, both frog and duck are fried at the same time in the stationary frame. And, both frog and duck will be fried in the train frame, despite at different times. But their frying at different times doesn't mean you can prevent the frog or duck from frying after the other one is fried. That would require sending a message faster than light, which means going back in time (does bring up paradoxes, but FTL is not possible according to SR).

Reread Einstein’s gendanken in his Special Relativity. The experimental set up is such that the rear and front of the train are located at A&B when the lightning flashes occur, i.e. those events happen simultaneously in the absolute sense for both the platform frame and the train frame. What is not simultaneous from one frame to the other are the reception of the signals from the events to the observers in the different frames. This however is hardly surprising since the train is moving towards one signal and away from the other signal when compared with the observer of the signals on the platform.

What is special about the platform frame is that since the observer is supposed to be at the midpoint of the flashes, she can only receive the signals simultaneously if she was really absolutely at rest- otherwise she would have to conclude that the speed of light measured from two different directions are not the same, contradicting the postulates of SR. So since an absolute rest frame was found it definitely makes life easier to measure all speeds relative to it. In reality the train experiment is of course flawed since the Earth is actually moving through space so that even the platform observer cannot receive the signals simultaneously.

But for amusement purposes, let’s assume that Einstein wasn’t talking about an absolute rest frame in his gedanken. It’s still absurd to use the reception time of signals as a representation of the sequence of how actual events occurred. If we see a star explode today from our telescope, who would be gullible enough to think that it happened today? So why do you make the case for relativity of simultaneity based on the reception time of the signals if in the absence of an absolute rest frame, it would be nigh impossible to determine the actual place in space when the light was produced nor our velocity through space, which surely must affect our determination of the speed of light since if the speed of light was truly constant in vacuo, if we have any motion through space, we will misjudge its true velocity. I don’t think this is a good reason to rid of absolute time do you? Really, which of you SR die hards can claim to have experienced any event that wasn’t absolutely simultaneous for everyone? If events were not absolutely simultaneous, your hand should have fell off from your wrist and your head from your body long before you finished typing your response.

 

[wespe]

... (post#485)

Ram,

I hate to tell you this but (A-B)/t + (B-C)/t = (A-C)/2t is wrong, it equals to (A-C)/t. I hope you won't discuss this or we have serious problems here.

Apart from that, I looked at your first picture. I'm not very familiar with spacetime diagrams. But, the picture looks upside down; conventionally, time axis should increase in the up direction.The angle between red and yellow lines should be 45 degrees (time and space units are chosen so that speed of light is 1). You should label things to avoid any confusion. See http://www.cord.edu/dept/physics/credo/spacetime.html
Also specify the values of speed, time, distance (chose convenient numbers).

Do that and ask what the diagram would look like from A's perspective according to SR. Obviously you don't know the answer. Just ask, don't draw conclusions. I'm not saying I can draw the correct skewed diagram, but I know the angle between the observer and light should always be 45 degrees. Perhaps someone here will help you if you show willingness to learn.

 

[wespe]

Reread Einstein’s gendanken in his Special Relativity. The experimental set up is such that the rear and front of the train are located at A&B when the lightning flashes occur, i.e. those events happen simultaneously in the absolute sense for both

sorry, we can't communicate if what you comprehend is that from reading http://www.bartleby.com/173/9.html

 

[ram1024]

http://www.imagedump.com/index.cgi?pick=get&tp=93385

happy now?

 

[ram1024]

sorry, we can't communicate if what you comprehend is that from reading http://www.bartleby.com/173/9.html

well that IS what it says.

When we say that the lightning strokes A and B are simultaneous with respect to the embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A —> B of the embankment. But the events A and B also correspond to positions A and B on the train. Let M' be the mid-point of the distance A —> B on the traveling train. Just when the flashes 1 of lightning occur, this point M' naturally coincides with the point M, but it moves towards the right in the diagram with the velocity v of the train. If an observer sitting in the position M’ in the train did not possesses this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A. Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A.

The conclusion is based off of not KNOWING he has moved any distance. Basically because of the distance unknown he has to assume his distances <measured on the train> are correct and that simultaneity is at fault, not any of his measurements.

 

[wespe]

well that IS what it says.

I'm sorry Ram, I can't communicate with you either.

It does NOT say "experimental set up is such that .. those events happen simultaneously in the absolute sense for both frames" as Eyesaw claims. It says the opposite.

Nice that you now corrected your diagram. Hope someone helps you with that. If not, you could try another forum.

 

[ram1024]

i'll break it down into parts with my translations, tell me where i go wrong.

When we say that the lightning strokes A and B are simultaneous with respect to the embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A —> B of the embankment

.

Observers taking the Embankment as a reference frame <stationary> will see that light from A and B hit M mid-point simultaneously

But the events A and B also correspond to positions A and B on the train. Let M' be the mid-point of the distance A —> B on the traveling train. Just when the flashes 1 of lightning occur, this point M' naturally coincides with the point M, but it moves towards the right in the diagram with the velocity v of the train

Assigning a point M' for the train reference frame such that at the precise instant any first flash of lightning hits "anywhere" M' coincides with M perfectly.

If an observer sitting in the position M’ in the train did not possesses this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated

If he didn't make any relative motion in relation to the embankment he would receive simultaneous light just as the embankment viewers.

Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A.

Reality is defined as REAL motion being made TOWARDS target light B and AWAY from target light A. Naturally this follows that he will see light B before light A.

Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A.

BUT if he takes his own reference frame as stationary, to him light would have to cover the SAME DISTANCES to reach him, but yet he receives light in staggered intervals. since light speed is constant, and the distances are the same <because he measures the distances in HIS frame (not including the distances he traveled in the embankment frame) he MUST conclude that God didn't turn the lights on at the same time.

<end interpretation>

 

[geistkiesel]

i'll break it down into parts with my translations, tell me where i go wrong.

.

Observers taking the Embankment as a reference frame <stationary> will see that light from A and B hit M mid-point simultaneously



Assigning a point M' for the train reference frame such that at the precise instant any first flash of lightning hits "anywhere" M' coincides with M perfectly.



If he didn't make any relative motion in relation to the embankment he would receive simultaneous light just as the embankment viewers.



Reality is defined as REAL motion being made TOWARDS target light B and AWAY from target light A. Naturally this follows that he will see light B before light A.



BUT if he takes his own reference frame as stationary, to him light would have to cover the SAME DISTANCES to reach him, but yet he receives light in staggered intervals. since light speed is constant, and the distances are the same <because he measures the distances in HIS frame (not including the distances he traveled in the embankment frame) he MUST conclude that God didn't turn the lights on at the same time.

<end interpretation>

Yes, in a sense. Here Einstein concludes that the mere fact that the moving observer measures the photon arrival at staggered intervals that the passengers on the train "must, therefore come to the conclusion" the photons were not emitted simultaneously in the moving frame. If this is true, your God solution fits the glove like a hand.

And are you familiar with the study that showed the differences in praying practices performed by persons praying in chrches versus those praying in gambling casinos?
The gamblers really mean it!

 

[geistkiesel]

Einstein's gedanken corresponds to your case#3. The moving observer does not see the lightenings at the same time (since they occurred simultaneously in the stationary frame, they can't have occurred simultaneously in the train frame). I am 100% sure this is SR's prediction. Plus, if he saw them at the same time, there would be a paradox, because the non-moving midpoint observer sees them at the same time at another point in space.

Your 100% assurance is not correct.

AE did not invoke SR to come to his conclusion. You are bootstrapping, it is called circuitous reasoning. AE came to the conclusion that because the B photon was detected before the A photon was detected that this alone is why the passengers "must therefore come to the conclusion" that the photons were not emitted simultaneously in the moving frame. Any SR imperatives, even if applicable and they aren't, would be swamped by the time difference between the time the B and A photon were detected. Ene Doc Al agrees with this.

But if you make the moving observer stationary, of course he sees the lightenings at the same time, because he would be in the stationary frame now. That would correspond to case#1.

I don't understand why you say "midpoint DOES move". The midpoint of events never move within any frame, because the location of events never move within a frame. Location of an event in a frame may look like moving from another frame (like burning marks on the train as seen from the embankement), but they would move at the same speed as the train.



For the hundreth time, there is no motion of the observer in the observer's frame, observer is at rest wrt itself. Of course separation speed changes when looked from another frame, but that's irrelevant. What changes in a frame is the simultaneity of events, not how light moves. That's the whole point you are missing.

Looking at these probkem by stopping one frame and moving another is grossly and physically impossible. Where do you get justification for this? Do you kinow? It is from hand me down mathematics isn't it?

This is not a photon problem. As stated above AE came tot he conclusion he diod based purely on the fact the B photon was detected earlier than the A photon. But AE did not discuss passengers at a and b located at A and B just as the photons were emitted and ercorded the train time of the events. The a and b clock are synchribnized wrt the moving frame. This inoformation senet immediately tio O' will arrive just as the A photon arrives. Also, observers loated at M just as the photons A and B arrived at M also record the time of arrival and send thir tiems tio O'. O' now has the arival time of A, the recorded times of the A and B emissions from a and b, and the recorded time the photons arrived simultaneously at M in the stationary frame. The clock information is convincing that the photons arrived in the moving frame simultaneously as measured by twp sets of passengers. Likewise, O' can calculate the simultaneity himself. After a little algebra,

t3 = t1(C + v)/(C - v).

Draw your own time and distance map, this is what you will get, if you keep SR out of the gthe picture, or even if you insist SR will be swamped. Try it out.

t1 is the time of arrival of the B photons measured from when the O' observer was at the midpoint M when the photons were emitted and v the known velocity of the train. t3 is also a measured quantity the time the A photon was detected by O'. calculation can determine the accuracy of the measured vs. calculated time t3.

Again SR affects, if any, will be swamped by the staggered times of the B and A photon arrival.

 

[Doc Al]

Your 100% assurance is not correct.

AE did not invoke SR to come to his conclusion. You are bootstrapping, it is called circuitous reasoning. AE came to the conclusion that because the B photon was detected before the A photon was detected that this alone is why the passengers "must therefore come to the conclusion" that the photons were not emitted simultaneously in the moving frame. Any SR imperatives, even if applicable and they aren't, would be swamped by the time difference between the time the B and A photon were detected. Ene Doc Al agrees with this.

Nonsense. The reasoning that Einstein uses in the train gedanken is SR in action, my friend. What Einstein invokes is the invariant speed of light: a key premise of SR. And what he concludes--The relativity of simultaneity--is a key result of SR.

And what are you babbling about SR "imperatives" being swamped by time differences? (Do you seriously think I agree with this gibberish?)

You, geistkiesel, are the true master of circular reasoning.

 

[geistkiesel]

Let me clarify.

The "moving" observer in Einstein Gedanken is M'. When the lightenings strike, M' is at the midpoint according to the embankement. M' then moves to the right, according to the embankement.

Correct so far.

[quote =wespe]Now, according to M', the lightenings don't strike simultaneously. So, when looking from M' frame, we can't actually say "M' was at the midpoint when the lightenings stroke", because that's not a single instant.[/quote]
Wrong, even from SR theory.

What is being measured is "events simultaneous in the staionary frame are not simultaneous in the moving frame". When M' was at M, the midpoint when the photons were emitted simultaneously does not allow the moving observer to say the moving iobserver was not at M when the photons were emitted simultaneously.This is a given, remember, you can't change the givesn. You can add observers, measuring equipment and the like, but changiong the giovens is a no no. This is one problem that SR invokes when "considering a moving frame stationary, a physical impossibility.

The moving observer concludes the photons were not emitted simultaneously, not from SR theory, but from the simple staggered measurement of the photons, first B then A, nothing else. SR follows this, it does not precede this experiment. You are close to being there.

But we can say "M' was at the midpoint of the locations where the lightenings stroke". Those locations are where the burning marks are made on the train (not the embankement, we are in the train frame now). Then, M' does not move anywhere (in his own frame, according to himself), thus remains at the midpoint of the events the whole time.

About your case #7 (post#249, took some time to find), all observers remain at the same distance from the location of any emitted photons (in accordance to what I wrote above). In other words, the location any event never changes *within a frame*. The event has happened at an instant and its location cannot be carried with the source of the event or whatever.[/QUOTE]

 

[geistkiesel]

Let me clarify.

The "moving" observer in Einstein Gedanken is M'. When the lightenings strike, M' is at the midpoint according to the embankement. M' then moves to the right, according to the embankement.

Correct so far.

Now, according to M', the lightenings don't strike simultaneously. So, when looking from M' frame, we can't actually say "M' was at the midpoint when the lightenings stroke", because that's not a single instant.

Wrong, even from SR theory. M' concludes the lighning doesn't strike simultaneously only from his staggered measurement of the B and A photon, nothing else. Stick to the experiment. read it again befopre yopu start showing off your Sr theory knowledge, which has a nother day or two to survive and that is just becasue ram1024 is extending a proferssional courtesy.

What is being measured is "events simultaneous in the staionary frame are not simultaneous in the moving frame". When M' was at M, the midpoint when the photons were emitted simultaneously does not allow the moving observer to say the moving was not at M when the photons were emitted simultaneously.This is a given, remember, you can't change the given. You can add observers, measuring equipment and the like, but changing the givens is a no no. This is one problem that SR invokes when "considering" a moving frame stationary, a physical impossibility.

The moving observer concludes the photons were not emitted simultaneously, not from SR theory, but from the simple staggered measurement of the photons, first B then A, nothing else. SR follows this, it does not precede this experiment. You are close to being there.

But we can say "M' was at the midpoint of the locations where the lightenings stroke". Those locations are where the burning marks are made on the train (not the embankement, we are in the train frame now). Then, M' does not move anywhere (in his own frame, according to himself), thus remains at the midpoint of the events the whole time.

Maybe so, but the moving observer will still detect the B photon before the A photon. The experiment doesn't change.The light apeed deos not depend on the velocity of the source.

About your case #7 (post#249, took some time to find), all observers remain at the same distance from the location of any emitted photons (in accordance to what I wrote above). In other words, the location any event never changes *within a frame*. The event has happened at an instant and its location cannot be carried with the source of the event or whatever.

I suppose so.

 

[geistkiesel]

Let me clarify.

The "moving" observer in Einstein Gedanken is M'. When the lightenings strike, M' is at the midpoint according to the embankement. M' then moves to the right, according to the embankement.

Now, according to M', the lightenings don't strike simultaneously. So, when looking from M' frame, we can't actually say "M' was at the midpoint when the lightenings stroke", because that's not a single instant. But we can say "M' was at the midpoint of the locations where the lightenings stroke". Those locations are where the burning marks are made on the train (not the embankement, we are in the train frame now). Then, M' does not move anywhere (in his own frame, according to himself), thus remains at the midpoint of the events the whole time.

About your case #7 (post#249, took some time to find), all observers remain at the same distance from the location of any emitted photons (in accordance to what I wrote above). In other words, the location any event never changes *within a frame*. The event has happened at an instant and its location cannot be carried with the source of the event or whatever.

I brought the point up in response to another post of yours. The observer only determines the photons were not emitted simultaneously from the staggered detection of the B and A photons, nothing more or less. You cannot stop moving frame and consider the other moving. This is SR stuff. This problem is not SR. The staggered detection of the B and A photon will swamp any SFR aspects of the experiment, which there aren't any anyway.

 

[wespe]

OK, one more try for Geistkiesel:

Suppose we have two space-trains passing by each other. They are moving inertially, but we don't know which one had accelerated in the past. No experiment can determine which train is "really" moving. We only know that they have a relative speed wrt each other. Now, suppose two explosions is space occur near the trains (but not tied to any of the trains, just instant explosions, at any two times, we don't know yet). The explosions create burn marks on both trains.

SR's claim is: if there were two observers at the mid point of those burn marks (measured in each train separately), they could determine the simultaneity of the explosions according to their train, by looking at the order they see the explosions, because speed of light is constant and distances are the same.

Now, if one of the observers see the explosions at the same time, the other will not. Because, the burn marks and the midpoints on two trains will have a relative speed wrt each other, and therefore the light from the explosions cannot hit both observers at the same time.

So tell me, if one observer sees them at the same time, and both events were simultaneous in both frames, and speed of light is independent of its source, why won't the other see them at the same time? You can't use the excuse "the trains were moving" or "one of them was stationary", because then you assume aether, and then you can't determine simultaneity in any frame with this method without knowing speed wrt aether. Are you saying that simultaneity is affected by speed wrt aether? So what method can you tell me to determine if two events occurred simultaneously, if we can't determine speed of a frame wrt aether? (of course in fact there is no sign of aether whatsoever)

 

[geistkiesel]

Nonsense. The reasoning that Einstein uses in the train gedanken is SR in action, my friend. What Einstein invokes is the invariant speed of light: a key premise of SR. And what he concludes--The relativity of simultaneity--is a key result of SR.

No SR is the key result of simultaneity, read the history sir.

BS. NASCARS are running invariant in speed in my example and you ignored that example. Eintein does not use any SR postulate in arriving at his conclusion. He uses only the the staggrered arrival of theh B photon and A photon as detected by the O' observer. You have said on many occasions that this is what all agree.

quote Doc Al "The fact (agreed by all) the light from B hits O' before the light from A leads the O' observer to conclude the lights could not flash simultameously."

Which leg standeth thee on oh master mentor?

And what are you babbling about SR "imperatives" being swamped by time differences? (Do you seriously think I agree with this gibberish?)

You, geistkiesel, are the true master of circular reasoning.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.

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.

How do you know this? They must check the times they are on opposite ends of the train, but each immediately relay their findings to O' who receives the data along with the simultaneous observation of the A and B photons arriving at M simultaneously.

You are invoking SR time dilation and mass shrinking right? What else could you be invoking to make your statement that the observers at A and B will not record the same time of the emitted photons. The photons know nothing of SR theory or even that there are two observers dutifully recording the times the photons are emitted. the a and b observers record the same time.

Remember, what you said back in the Lost simultaneoity thread. let me remind you:
quote by Doc Al
"If you understood the Eisntein simple argument you would know that nowhere does "time dilation" or " mass shrinking" enter into it"

 

[geistkiesel]

Quote:
Originally Posted by Eyesaw
Actually my suggestion is that you try running from the burn marks on the track until you catch up to the observer inside the train and then tell us if there is a difference between running just from the burn marks on the train to the middle of the train.




Reread Einstein’s gendanken in his Special Relativity. The experimental set up is such that the rear and front of the train are located at A&B when the lightning flashes occur, i.e. those events happen simultaneously in the absolute sense for both the platform frame and the train frame. What is not simultaneous from one frame to the other are the reception of the signals from the events to the observers in the different frames. This however is hardly surprising since the train is moving towards one signal and away from the other signal when compared with the observer of the signals on the platform.

What is special about the platform frame is that since the observer is supposed to be at the midpoint of the flashes, she can only receive the signals simultaneously if she was really absolutely at rest- otherwise she would have to conclude that the speed of light measured from two different directions are not the same, contradicting the postulates of SR. So since an absolute rest frame was found it definitely makes life easier to measure all speeds relative to it. In reality the train experiment is of course flawed since the Earth is actually moving through space so that even the platform observer cannot receive the signals simultaneously.

But for amusement purposes, let’s assume that Einstein wasn’t talking about an absolute rest frame in his gedanken. It’s still absurd to use the reception time of signals as a representation of the sequence of how actual events occurred. If we see a star explode today from our telescope, who would be gullible enough to think that it happened today? So why do you make the case for relativity of simultaneity based on the reception time of the signals if in the absence of an absolute rest frame, it would be nigh impossible to determine the actual place in space when the light was produced nor our velocity through space, which surely must affect our determination of the speed of light since if the speed of light was truly constant in vacuo, if we have any motion through space, we will misjudge its true velocity. I don’t think this is a good reason to rid of absolute time do you? Really, which of you SR die hards can claim to have experienced any event that wasn’t absolutely simultaneous for everyone? If events were not absolutely simultaneous, your hand should have fell off from your wrist and your head from your body long before you finished typing your response.

Where in the hell have you been hiding?

 

[Eyesaw]

OK, one more try for Geistkiesel:

Suppose we have two space-trains passing by each other. They are moving inertially, but we don't know which one had accelerated in the past. No experiment can determine which train is "really" moving. We only know that they have a relative speed wrt each other. Now, suppose two explosions is space occur near the trains (but not tied to any of the trains, just instant explosions, at any two times, we don't know yet). The explosions create burn marks on both trains.

SR's claim is: if there were two observers at the mid point of those burn marks (measured in each train separately), they could determine the simultaneity of the explosions according to their train, by looking at the order they see the explosions, because speed of light is constant and distances are the same.

Now, if one of the observers see the explosions at the same time, the other will not. Because, the burn marks and the midpoints on two trains will have a relative speed wrt each other, and therefore the light from the explosions cannot hit both observers at the same time.

So tell me, if one observer sees them at the same time, and both events were simultaneous in both frames, and speed of light is independent of its source, why won't the other see them at the same time? You can't use the excuse "the trains were moving" or "one of them was stationary", because then you assume aether, and then you can't determine simultaneity in any frame with this method without knowing speed wrt aether. Are you saying that simultaneity is affected by speed wrt aether? So what method can you tell me to determine if two events occurred simultaneously, if we can't determine speed of a frame wrt aether? (of course in fact there is no sign of aether whatsoever)

Two trains have a relative speed. They both have burn marks on the front and rear and both observers are at the midpoint of their train. So if the speed of light is constant in vacuo how can either, or any observer for that matter, detect the explosion flashes simultaneously inside their own frame unless they were at absolute rest ? I'd like to hear your response on this point before I comment on the rest. I'm sure your response will involve a discussion about length contraction/time dilation so I'm curious how this will work. Seems to me that one half of the train should be contracted while the other half expanded for this to work, and how much contraction/expansion dependent on the frame observing the rest frame. Well, sorry but this sounds ridiculous.

 

[Eyesaw]

Another point I am confused with is this: if any inertial frame can consider themselves to be at the center of arbitrary emission events, doesn't that equate with the emitters of the light being at rest with respect to each inertial frame? If so, how can any inertial frame detect doppler shifting of light from two continuous emission sources? That is, if there is never any relative velocity between emission sources and the detection frame, how could light be doppler shifted in different inertial frames? Or if Doppler shifting of light was allowed, surely the observer that detects the flashes as non-simultaneous can deduce that his frame was in motion relative to the light emitters and hence the actual time of occurrence of the events?

 

[Eyesaw]

Where in the hell have you been hiding?

Well you and ram are tough acts to follow so I've basically been reading.

 

[ram1024]

heh, geist is scary. he'll be all quiet and calm for a week then BAM he'll jump in with a sledgehammer and hit you with pages worth of arguments.

 

[Eyesaw]

Geist writes very well, wish I can do that. Those defending SR here are also brilliant but they have a much more difficult task imo because they are trying to make something that is pretty nonsensical sound rational.

 

[geistkiesel]

Two trains have a relative speed. They both have burn marks on the front and rear and both observers are at the midpoint of their train. So if the speed of light is constant in vacuo how can either, or any observer for that matter, detect the explosion flashes simultaneously inside their own frame unless they were at absolute rest ? I'd like to hear your response on this point before I comment on the rest. I'm sure your response will involve a discussion about length contraction/time dilation so I'm curious how this will work. Seems to me that one half of the train should be contracted while the other half expanded for this to work. Well, sorry but this sounds ridiculous.

Excuse me for butting in like this but here is one possible soluiton.If I understand the problem we could have a situation like the following.

            o ____________m1____________0 ->v1


                  \   /         \  /
                   x1            x2
                  /  \          /  \
                     

  <-v2        o___________m2_____________o

As I have drawn the situation the explosions at x1 and x2 are simultaneous and arrive at the midpoints of each moving frame, by sheer luck, but it is consistent.
The diagram is a set of equilateral triangles here each moving frame is located such that the photons from the explosions arrive simultaneously at the midpoints and end points of each train simultaneously. However the photons do not necessarily arrive on each train at the same time. The arrive on the trains simultaneously. Well maybe with a slight discussion.

The bottom train where the triangles are true equilaterals the photons arrive at the end points and the center point simultaneously. In the other train which may be say twice as far from the explosions as the first, the photons can arrive at the midpoint before the photons arrive at the end points. However, each conclusion will be the same the photons were emitted simultaneoulsy as this is what was observed. It would be a mistake to link the two frames which are completely independent of each other to say that if one sees the explosions simultaneously the other cannot see the explosions simultaneously,

It might help to have clocks that stop when the explosions reach the trains, which would end the speculation.

As I contrived the experiment it is possible for the frames, or an infinite number of frames, to see the explosions as simultaneous. A contrived situation, but possible.

 

[ram1024]

which has a nother day or two to survive and that is just becasue ram1024 is extending a proferssional courtesy

i'm wondering how the heck he knew i was holding something back :O
trying to be unpredictable and he's reading my game

 

[geistkiesel]

Another point I am confused with is this: if any inertial frame can consider themselves to be at the center of arbitrary emission events, doesn't that equate with the emitters of the light being at rest with respect to each inertial frame? If so, how can any inertial frame detect doppler shifting of light from two continuous emission sources? That is, if there is never any relative velocity between emission sources and the detection frame, how could light be doppler shifted in different inertial frames? Or if Doppler shifting of light was allowed, surely the observer that detects the flashes as non-simultaneous can deduce that his frame was in motion relative to the light emitters and hence the actual time of occurrence of the events?

I am not sure i have you exactly as you mean, but here is a try.

I have used the dopller shift argument to explain away the claim that two frames cannot determine which is moving with respect to whom. In the standard Einstein train station moving train experiment the flashes can occur in either frame. The frame not holding the source of the emitted photons would naturally see a doppler shift.

Another way to tell how each frame is in motion with respect to the other is to look at the acceleration data of each frame. If three frames were at one time at rest wrt the earth, for instance and each acceleratss, one for 1 g for 5 minutes, another 1 g for 7 minutes and the thirid 1 g for 10 minutes and knowing the mass of each, (easy if standardized frames), relative velocity could be defined by such information.

 

[wespe]

Two trains have a relative speed. They both have burn marks on the front and rear and both observers are at the midpoint of their train. So if the speed of light is constant in vacuo how can either, or any observer for that matter, detect the explosion flashes simultaneously inside their own frame unless they were at absolute rest ? I'd like to hear your response on this point before I comment on the rest.

From that, I guess you are imagining that speed of light is constant with respect to "aether". No, speed of light is measured the same in all frames (counter intuitive, but experimental fact). Also, I guess you are imagining that the explosions occurred simultaneously according to "aether". I didn't say that. They just occur at two times, that's not given. We are investigating wheter they occurred simultaneously according to the two trains, by using the two midpoint observers. And they won't agree about simultaneity, that's the main point.

Does that clarify?

 

[geistkiesel]

A Modified ram1024 buoy? or is ot the same?

i'm wondering how the heck he knew I was holding something back :O
trying to be unpredictable and he's reading my game

I have a mofdified ram1024 buoy. It might be the same so let me know. It is a six sided cube, for three directions of motion to cover. Assume each set of parallel sides has its own photon source at the midpoint of the sources. If the buoy is moving in one direction, say along the x-axis the return reflections from the two sides is detected at the midpoint and a relative velocity wrt the light speed is detected.

The surfaces of the mirrors have photon detectors that determine the time the photons arrived and hence determine the speed and direction direction (hey that's velocity) and by applying a little braking force the x direction velocity can be minimized to what, zero, of course. (I am using a modified Einstein gedanken; The photons moving in the diretion of motion will take longer to reach its intended surface than the light directed at the surface closing in on the oncoming photon. Sounds like more of an engineering problem than physics.)The other two directions can be manipulated the same. In fact the calculations of the velocity in the three directions can be calculated more or less at the same time, ergo, the buoy can be brought to zero velocity, wrt to the speed light., fairly quickly. This would give a very accurate zero velocity - 1 part in 3x10 ^8m/sec for +- 1 meter, better if using centimeter or millilmeter, or what evere the creative genius of the current inertial frame engineers determines.

The rest of the moving stellar objects in the universe can move as they will, but one buoy can determine a zero velocity wrt c.

Is this in line with the ram1024 version? Each frame can radiate a number giving its relative absolute velocity or error correction information. Why would any SRist want to complain about at least trying something like the ram1024 buoy? Hell we've got all the money in the universe, effectively, we being the us of a.

I would only caution about trying to correct all three directions at the same time, after all Mother Nature's last act before launching her creation as a universe was to add time so everything wouldn't happen all at once.

 

[ram1024]

heh it is quite similar to the URF Space-Buoy, but that was a creation i made knowing it would fail, not according to SR precepts per se, but due to my own.

the problems that arose with it were the need to calibrate it accordingly. i had used clocks synchronized at zero-point and then moved into positions using and intricate and precise technique, but SR people refused to let that be the true deciding factor for the device.

they did allow me to synchronize using the midpoint as simultaneous light reception. what this would do would allow the device not to be able to find the Universal Reference Frame (Absolute Stationary), but instead allow the device to calibrate to one specific inertial frame, and be able to detect any deviation from this frame precisely.

in this sense we could define frames throughout the universe simply by knowing the values of deviation from our defined "earth frame". A buoy with known "Earth Frame" values could be set up in another system light years away to measure "Earth Frame" in respect to "That Other System's Frame" just by letting the buoy jet until it reaches "Earth Frame Equilibrium"

hmm didn't mean to write a novel :D but yeah, technically according to SR's constant light speed thing the device you described would have to work... but only if they allowed zero-point synchronization

 

[wespe]

Another point I am confused with is this: if any inertial frame can consider themselves to be at the center of arbitrary emission events, doesn't that equate with the emitters of the light being at rest with respect to each inertial frame? If so, how can any inertial frame detect doppler shifting of light from two continuous emission sources?

An observer can consider himself to be at rest with the emission point of a single photon, regardless of the relative speed of the photon source. Also same with successively emitted photons, but the emission point for those successive photons will be getting closer/farther as the source moves, so the final effect is doppler shift.

That is, if there is never any relative velocity between emission sources and the detection frame, how could light be doppler shifted in different inertial frames?

I'm a bit lost here. If there is no relative velocity between emitter and detector, ther is no doppler shift. Are you imagining that light itself gets modified? Detected frequency/wavelength is a relation (can't find a better word for this right now) between emitter and detector, light itself remains same.

Or if Doppler shifting of light was allowed, surely the observer that detects the flashes as non-simultaneous can deduce that his frame was in motion relative to the light emitters and hence the actual time of occurrence of the events?

If I don't misunderstand you, no, doppler shift can't be used to detect absolute motion, because it doesn't matter if the emitter or detector is "moving", only relative speed matters.

 

[Chronos]

Physics 101

 

[wespe]

heh, geist is scary. he'll be all quiet and calm for a week then BAM he'll jump in with a sledgehammer and hit you with pages worth of arguments.

I'd say more like frustrating. At some point you will wear everyone out. What you guys are doing isn't anything like physics. You are just rejecting SR because it seems to defy common sense, which we all understand (no we aren't crazy). But you can't ignore experiment results which are in accordance with SR, not the intuitive Gallilean relativity (I'm not sure Geistkiesel understands even that). Other people aren't stupid, not to mention 100 years of brain power combined. You can see I'm frustrated with you Ram and Geistkiesel too.