Tutorial: Relativity of simultaneity

[Neddy Bate]

QQ:



Yes. All EVENTS happen in all frames. If I eat a sausage in one frame, then I eat it in all frames. Anybody watching me sees me eat it, at some time or other.

Events are absolute. Everybody agrees on WHICH events happen. They just don't agree on WHERE and WHEN they happen.

Is this another way of saying that the "total time" (for lack of better term) is equal in all relatively moving inertial frames of reference? For if reciprocal time dilation becomes a matter of WHERE and WHEN, but not HOW MUCH time, this would imply that, in the end, the dilated time does not go missing, but rather it would seem that it must be assigned back to its frame eventually. It seems that we have introduced a philosophical contention that there must be some 'absolute' amount of time underlying an illusion of reciprocal time dilation.

And even if we conserve "total time" (HOW MUCH time), what shall we do with the relativity of WHERE and WHEN? A sausage-stealing object (from a different reference frame) would not be allowed to collide with a sausage before you eat it, if you have already eaten it in your frame of reference. As QQ pondered earlier, where is the NOW? The only way any collision would be allowed would be if we introduce a philosophical contention that there must be some 'absolute' simultanaety underlying the illusion of non-simultanaety.

 

[James R]

Neddy,

I'm not sure I understand your point. However, I disagree that there needs to be any "absolute" time underlying anything.

A sausage-stealing object (from a different reference frame) would not be allowed to collide with a sausage before you eat it, if you have already eaten it in your frame of reference.

That is true. This is a problem of causation. After I have eaten the sausage in my reference frame, nothing can then come along and prevent me having eaten it. This is equivalent to saying that no causative influences can travel backwards in time, in ANY reference frame.

This is no problem for relativity. The concept of light cones can help understand this. An event can only ever affect other events in its forwards light cone, and it can only ever be affected by events in its backwards light cone. Which events are when is absolute. If an event A is in the backwards light cone of event B in one reference frame, then it is in the backwards light cone in ALL reference frames.

 

[Quantum Quack]

Neddy, JamesR's contention is further supported by a post by 1100f in another thread currently running:

"From Lorentz transformation, two events that occur at the same time and at the same place in one reference frame, will always occur at the same time and same place in any other reference frame.

Here the two events are the arrival of the photon that comes from the mirror A1 at A2, and the second event is the arrival of photon that comes from rocket B to the mirror A2. In the reference frame A, those events occur at the same place (position of mirror A2) and at the same time, so in the reference frame B, they will occur at the same place and same time."

Whilst this Th. Exp. has yet to prove the above to be true it is an interesting pronouncement all the same......

 

[geistkiesel]

Originally Posted by geistkiesel

No, I do not believe that the earth is siitting in a state of absolute velocity = zero rest. I say that in the measurement of light the motion of the earth does not insert errors that cannot be determined and therefore removed.


Sorry? Are you denying or affirming the invariance of c? Because if there are no error to be determined...

No the earth is not sitting in a state ovf zero motion and measurements can be made such that the errors introduced by the earth motion can be corrected for.

Assume the sun is dragging the solar system along with it at 208 km/sec.

With respect to what?

Some distant star with a measured v =0.

Geistkiesel said
Look at it like this. Virtually every inertial frame Vf that moves wrt the embankment, the earth, has accelerated wrt the embankment, Ve.


But where is the embankment? Is that at rest?

The embankment is the surface of the planet earth,

Geistkiesel said,
The Ve has never been observed to accelerate in the sense that Vf accelerates and produces a relative motion wrt Vf and Ve. Here, however, we know apriori, that it was the Vf that accelerated, not the Ve, therefore why pretend the silliness of asuming the Vf is ever at rest wrt Ve


I don't think anybody is claming that. Relative rest is rather dull.

They claim the passenger trains are at rest while the train stations are "seen"whizzing ion by. Where have you been lately?

SRT claims the equivalence of inertial frames and passenger train examples are sumerous claiming the train can "consider it self at rest wrt the emabnkment" a physically impssible condition to achieve.

Geistkeisel
Because you can move your pencil over the surface of a piece of paper and crunch out the 'theory' that the Vf, say a passenger train, could, once a relative motion wrt Ve is observed, ever be at rest and the Ve be moving with relative velocity VF (which must be the measured relative velocity.). This is physically impossible condition to achieve, and all the theory in the universe is not going to change that reality.

The frames are not equivalent. Ve and Vf, that is. Only Vf accelerates with rspect to Ve and you cannot come back a week after the acceleration event and say, "I've forgoptten all about my previous accelreated statethe fact taht I have moved, so I'll just assume SRT as the fix for the lapsed mermory.


Ok. Then where is the primordial embankment?

What the hell is a primordial embankment? Is this supposed to be a funny, or a serious question regarding the laws of physics?

Geistkiesel said
SRT preaching the mantra that the relative velocity of frame and photon will always measure C is sheer nonsense.

Ah, denying it. Then the onus is on you to find, say, a sub- or superluminal photon in a vacuum. And an explanation for gravitational lensing. Oh, and explain why relativistic effects need to be accounted for in GPS. And find the absolute rest frame. And an explanation for the precession of the perihelion of Mercury. And an explanation for the frame dragging effects recently confirmed. And explain why those atomic clocks don't match up.

Common sense does not override reality.

Please define common sense. I bet that the common sense you have is the good stuff, right? The commn sense that you have, I mean, right??

A pair of photons emitted simultaneously from a point on a frame defines, a zero point reference for a perfect zero velocity FOR.

Geistkiesel said,
To assume this universally is to ignmore even the possibility of , or need to measure the relative velocity of frame and photon. This says that never in the development of human technology will there be a possibility to do what is claimed to be impossible.

Measuring the velocity of the frame and a photon is easy.

yes it is easy. Easier still is to measure the relative velocity of frame and photon as C + v or c - v depending on direction of the frame wrt the photon direction of motion.

Geistkiesel said,

...the relative velocity of frame and photon will always be measured at C..
.
The frame at c relative to some rest frame?!?

Well, one can use the velocity of the emitted photns to calibrate the velocity measure re teh phoiton trajectories which comprise the rfame proper.

Geistkiesel said,
Remember, the invariant location of the emission point of the photons.

This is just another way of saying "absolute space and time".

All I said was that the emission point was invariant, from any physiocal intervention, once the point is defined. Yes, it is another way to describe absolute space and time. After all, that is the way it is.

Geistkiesel said

Are you able to prove with certainty that the photons will arrive at L and R simultabneously ? Prove it I mean. Don't ask me what I believe, look at the problem and solve it. You are unable to do so without draggng cliched formulae from off the shelf, correct?.

First, if you use the "consideration" of the moving observer as a crucial condition in your conslusion you have failed.

In other words, if we don't accept absolute space and time we have failed. Sorry, no-can-do.James R's analysis, given the invariance of light speed, is perfectly correct: The rod clocks will show the same time when the photons hit. You may not believe that this is true for the real universe, but the thought example is unassailable.

Given the invariance of the SOL gives us absolute space and time. It is the measure of relative velocity of frame and photon that is mistaken by SRT. Look at the gedanken, the measurements of the SOL are wrt the invariant point of emission of two photons moving in opposite directions. Even one emitted photon defines a FOR: there is a zero point and a trajectory line both invariant spatially.

FYI the expression c- v is a measure of the difference in speeds of c and the frame, it is not a measurement of the SOL less than c. Also, c + V does not grant the SOL values > c it merely reflects the measured relative velocity of frame and photon moving in oppposite directions wrt each other. What is wrong with this?
.
No, if you deny that the emitted photons define an invariant point in space you have failed. If you cannot see that the trajectories of the emitted photons define an invariant straight line then you have failed. Someone told you to deny absolute space time reality under any reply or attack which is what you do with slavish obedienece. You fear even to hypothecise something anathemic to your SRT.

Geistkiesel said,
In the experiment in the figure all time measurements are wrt the moving clocks.

Sure, if space and time are absolute, and the point of emission is at rest (meaning fixed) in this frame.

The point of emission and the projected trajectory of the photons is the frame. Don't you get it yet?
What do you object to when the photons are emitted, that they aren't moving at the speed of c wrt the emission point? Is this what you are saying?

Geistkiesel said
There is symmetry in the ML and MR distances M being the midpoint of the L and R clocks. See if you can follow the logic of the development of the t' expression.

Ask yourself just one question. When the left photon has moved ct and arrived at L the right photon has moved an equal distance has it not? I am not asking about any frame motion here.

When thje left photon then reflects back to the emission point it has travelled another ct distance right? ALso the right photon has travelled ct. But the photons do not arrive at the L and R clocks at the same time because the fucking frame id moving.

I am not saying absorbed what I say is the truth, I say just analyze the problem wrt the photon motion motion

All this, with except for the moving clocks reading different times, is largely what the stationary observer sees.

So what that stationary observer sees it also. This cooincidental. Take the exeperiment to empty space and conduct the same experiment.

Geistkiesel said,
Assume the experiment has been run 10,000 times using the same relative velocity every time. Then the stationary observers can place clocks exactly at the locations of the L and R clocks when/where the photons arrive, correct? We can get the same results using stationary clocks even, but the difficulty you have is to argue away that two clocks colocated, one moving, the other stationary, (really stationary) will not record the arrival of the photons at the colocated positions simultaneously.
Go for it.

If time and space are absolute, then, of course, you're right. If you want us to show relativistic effects in a Newtonian universe, then, of course, we can't.

Are you saying that the "absolute space and time" words, that you brought up, recognizing the implications of what you were looking at is sufficient to distract you from a detailed analysis of the gedanken? because you haven]t done this have you? You cannot find an error in logic or phyiscs so you revert to cliche'd SRT. When you studied and accepted SRT you bought into a crock of shit and now personal pride refuses to allow you even the consideration that a smart cookie like yourself was hoodwinked, baited and reeled in by a smooth talking SRT prof,

If time and space are absolute, then, of course, you're right. If you want us to show relativistic effects in a Newtonian universe, then, of course, we can't.

But this universe does not appear to be Newtonian.
04-14-05 04:57 PM But this universe does not appear to be Newtonian.

The gedanken that you are responding to sure seems Newtonian doesn't it? You have found no holes in the specifics have you? What just is your problem with absolute space and time, these words aren't allowed in your club, are they?
The universe sure appears to be Newtonian to me.

Show us what you have and defeat the post here. Ths is why you showed up in the first place isn't it?

Geistkiesel ​

 

[Quantum Quack]

Geist, from what I understand you are saying:

That if light is emitted from a common source and in all directions it travels the same distance in the same time that would indicate absolute rest.

OK lets ponder on this for a moment.......


In absolute terms: we know that velocity transforms the length in the form of contraction. So to follow the simple logic if any velocity is present there must be in absolute terms some form of length contraction.
So there fore if the photons travel in all directions the exact same distance in teh exact same time we should have a poition of absolute rest.

Now of course you realise we are using SRT principles to discover our absolute rest frame. And that SRT forbids the finding of absolute rest.

The reason I think is that any frame can give us a premise of rest, regardless of it's velocity. That light can travel in all directions the same distance and in the same time equally regardless of the actual velocity of the frame. In fact I think this is exactly how SRT accomodates the postulate of invariance.

However if we reverse the logic and see another frame demonstrating such attributes as described from a position of known velocity what does this prove?

It would show a frame at absolute [spatial] rest I think.
Thus absolute spatial rest can only be determined form a frame with velocity.

The paradoxical effect of contractions and dilations not being noticed by the frame observer, fundamentally when using SRT means that to find absolute spatial rest is perceptionally impossible. "How can something be seen to be more at rest than your self?"

Unfortuinately a frame at absolute rest could argueably cease to exist depending on how deep you want to go with the logic. [which is why I have introduced the term " absolute spatial rest"]

 

[Quantum Quack]

Also the only object or entity that can be deemed as being at absolute rest at this level of definition is our photon. So you woudl have to slow the frames velocity so that the photon is still and not travelling. Even then the frame still changes at 'c' but has no relative velocity to the universe. [the whole universe and teh photon are at relative rest, so therefore the universe changes with the photon as a contantly evolving NOW].... [this I believe is outside SRT understanding].

My thoughts

 

[geistkiesel]

Geist, from what I understand you are saying:

That if light is emitted from a common source and in all directions it travels the same distance in the same time that would indicate absolute rest.

Absolute rest of the emission point, is what Iwas referring to, just to clarify.

OK lets ponder on this for a moment.......


In absolute terms: we know that velocity transforms the length in the form of contraction. So to follow the simple logic if any velocity is present there must be in absolute terms some form of length contraction.

So there fore if the photons travel in all directions the exact same
e distance in the exact same time we should have a position of absolute rest.[/quote]
I was struggling thee for a sec, but I think I am back on track.
OK I am with you. You are saying that in order for the photons to exhibit uniformity, invariance and isotropic motion then the contraction and dilation must be nonexistent, otherwise we have a glaring contradiction to the constancy of the speed of light.

Further, all the relative velocity must be intrinsically contaoined exclusivley in the other frame. [But then this frame with photon emitetrs iteself woulfd be subject tothe same limitations, the effect on SRT of this is getting rather ugly for some I imagine. Wel if their mothers let them read this stuff that is.]

Now of course you realise we are using SRT principles to discover our absolute rest frame. And that SRT forbids the finding of absolute rest.

The reason I think is that any frame can give us a premise of rest, regardless of it's velocity. That light can travel in all directions the same distance and in the same time equally regardless of the actual velocity of the frame. In fact I think this is exactly how SRT accomodates the postulate of invariance.

OK, this seems reasonable. This is my understanding.

However if we reverse the logic and see another frame demonstrating such attributes as described from a position of known velocity what does this prove?

Are you saying another frame has noticed the photons on that other frame expanding with no contraction obsevred? Meaning, in other words, the isotropic motion of the photons in a "supposed" moving frame, is observed meaning the contractions and dilations are missing?

It would show a frame at absolute [spatial] rest I think.
Thus absolute spatial rest can only be determined from a frame with velocity.

yes, if the other frame saw isotropic photon behavior it would not measure contraction or dilation in the frame of interest here. In fact complete isotropic light motion is equivalent to a void in measured contractions and dilations using SRT. I am assuming there is a measured relative velocity throughout all this.

, fundamentally when using SRT means that to find absolute spatial rest is perceptionally impossible. "How can something be seen to be more at rest than your self?"

If You are saying that a frame that observes isotropic light motion cannot consider itself at rest in the reality of a measured relative velocity wrt each other, then I agree. How can an observed absolute zero velocity be moving and contributing velocity to the measured relative velocity? It can't!

Unfortunately a frame at absolute rest could argueably cease to exist depending on how deep you want to go with the logic. [which is why I have introduced the term " absolute spatial rest"

I don't see how you get the demise of the frame for the mere condition it is at absoluite rest. It is just at rest, as measured in the photon emission point and trajectory FOR.
You will have run this by me again, the demise of the frame at rest I mean. I can "see" the demise of SRT in this condition, but I am going to give the frame another chance to prove its existence. Ha Ha.



Geistkiesel​

 

[geistkiesel]

Also the only object or entity that can be deemed as being at absolute rest at this level of definition is our photon. So you woudl have to slow the frames velocity so that the photon is still and not travelling. Even then the frame still changes at 'c' but has no relative velocity to the universe. [the whole universe and teh photon are at relative rest, so therefore the universe changes with the photon as a contantly evolving NOW].... [this I believe is outside SRT understanding].

My thoughts

It is getting late for me. My mind/brain is starting to implode going over the last post of yours above. I will 'grok' this one here and get back to you. I think I will let the sandman solve this one and simply wake up with a rational response in my new day's first yawn..

Geistkiesel​

 

[Quantum Quack]

The question comes down to this:

If I am in a rest frame and a ship passes by me at 0.8c. I send him a photon that penetrates his ship and bounces around inside his ship, does the photon maintain the same speed as it did when it left my rest frame?

To me the answer has to be yes it does maintain the same speed if invariance is to be maintained as valid.
Now if the photon maintains it's speed on board the ship, the ship has to be contracted in length and dilated in time so that that photon appears to be at 'c' to the ships observer. so essentially the ships length and tick rate is relative to the light which is constant.

In other words the L. transforms allow us to fiddle with the volume and passage of time of that volume to accomodate the relative velocities of the frames but with out changing the velocity of light.

Please correct me if I am wromg on this as this is a fundy of SRT I hope I have got right for a change....

It's the old "One factor is constant and change everything else to keep it that way - routine" [ BTW I don't seee anythign wrong with that]

Underlying this [not within SRT understanding at present] is the fact that the ship is contantly changing within itself at the same rate as the photon plus what ever velocity it is travelling.

ie. As the photon travels 1 second aboard ship the ship has also traveled one second within itself plus the distance it has traveled externally.

So to achieve a position of absolute spatial rest the ship has to slow so that the photon does not travel and the ship and the photon move as one frame.

So therefore zero velocity in normal terms is 'c' and any velocity beyond 'c' is what we call normal velocity. so you have [ 'c' * the v of the ship] which is why it contracts and dilates so that 'c' it's universal rest velocity is maintained thus the photon remains invariant to all inertial observers.

If this was not the case the photon would become visable and an object of mass.
[Someone mentioned blue chenekov radiation in another thread.]

I comes back to E=mc^2 if an object of mass is accelerated to an ordinary velocity of 'c' it is in effect travelling at c^2 thus it's full energy potential is realised. [and of course it is no longer an object of mass but pure light or energy]

 

[Quantum Quack]

geist a diagram that may clear up this time in continuum thing.

The photon moves from left to right. The numbers are time intervals for the entire frame. 1-6 The frame and the photon have accumulated 6 units of time together.
As the photon is the fastest anything can go and can not go slower than 'c' in a vacuum it makes sense to state that the frame has travelled the same amount of change as the photon has undergone. It can then be further stated that the photon and the frame are not relative in time. The NOW is thus absolute for both photon and frame.
and any velcoity the frame has is added to it's inherant 'c' however dilation and length contraction negate any ordinary velocity therefore maintaining that inherant 'c'.

c*v-Length contraction - dilation = 'c' thus light is maintained as invariant for all observers.

for example an object travelling at 0.4c

lights v= c*0.4c
when dilation and length contractions are accounted for the v=c thus light's invariance is maintained.

I would be very confident that the L transforms were created with this premise in mind.....essentially built around E=mc^2. But maybe someone can correct me if I am wrong

 

[superluminal]

QQ:

Please correct me if I am wromg on this as this is a fundy of SRT I hope I have got right for a change....

It's the old "One factor is constant and change everything else to keep it that way - routine" [ BTW I don't seee anythign wrong with that]

You have it right. Remember that physicists dont decree any of this (despite claims of 'fiat' and 'ignorant establishment acceptance of counterintuitive rubbish fed to the brainwashed masses'). They were eager for there to be an ether - it would have made life so much easier... But they found, and continue to find, none. They also measure light speed all the time in all sorts of ways and find it to be constant no matter how the test setup is moving. Rats.

With these FACTS in hand, you write equations that describe what's really going on, and you just have to accept the consequences of the FACTS.

 

[funkstar]

It's interesting to ponder what an absolute rest frame (being the only one with constant light speed) would actually entail. It's a fair assumption that the sun would not be at rest in such a frame, I should think:

The most striking example I can think of, is that we'd get red and blue-shift of sunlight at various times of the year. Same with the stars.

Of course, the motions of the planets would also be very strange to look at.

Doppler measurements of speed would have to be correlated with the rest frame, because the red-shift would change.

Electronics with tight timings would be need those timings relaxed, because orientation would affect propagation times.


The universe would probably look quite a bit stranger if light speed wasn't invariant.

 

[Prosoothus]

superluminal,

You have it right. Remember that physicists dont decree any of this (despite claims of 'fiat' and 'ignorant establishment acceptance of counterintuitive rubbish fed to the brainwashed masses'). They were eager for there to be an ether - it would have made life so much easier... But they found, and continue to find, none. They also measure light speed all the time in all sorts of ways and find it to be constant no matter how the test setup is moving. Rats.

With these FACTS in hand, you write equations that describe what's really going on, and you just have to accept the consequences of the FACTS.

There are "FACTS", and then there is "JUMPING TO CONCLUSIONS". You have to remember that every experiment that was done to detect an "aether" was done on the surface of the Earth, stationairy in the Earth's gravitational field. It's possible that the Earth's gravitational field is actually dragging the "aether" around, or that the gravitational field is itself the aether.

Also, don't forget that Einstein predicted a phenomenon called "frame-dragging" in which masses drag "frames" around. If the omnidirectional speed of light is only equal to c relative to Einstein's "frame", then the fact that the speed of light is equal to c on the surface of the Earth can be easily explained without time dilation and length contraction.

Although some people may find it offensive, I believe that Einstein acted unscientifically when he assumed that since the omnidirectional speed of light is equal to c on the surface of the Earth, in a device that is stationairy in the Earth's gravitational field, that its speed must be equal to c for all inertial observers everywhere in the universe. That's like me dropping a rock on the ground and concluding that 10 m/s^2 is a universal constant.

 

[MacM]

Although some people may find it offensive, I believe that Einstein acted unscientifically when he assumed that since the omnidirectional speed of light is equal to c on the surface of the Earth, in a device that is stationairy in the Earth's gravitational field, that its speed must be equal to c for all inertial observers everywhere in the universe.

Toche! There damn well are other conclusions and alternative explanations.

 

[funkstar]

They claim the passenger trains are at rest while the train stations are "seen"whizzing ion by. Where have you been lately?

SRT claims the equivalence of inertial frames and passenger train examples are sumerous claiming the train can "consider it self at rest wrt the emabnkment" a physically impssible condition to achieve.
​

Why?

What the hell is a primordial embankment? Is this supposed to be a funny, or a serious question regarding the laws of physics?

I'm asking you where the absolute rest frame is. If you claim that there's some "memory" of relative acceleration, then what that relative acceleration was originally with respect to, is a very reasonable question.

Please define common sense. I bet that the common sense you have is the good stuff, right? The commn sense that you have, I mean, right??

Please don't get hysterical. I find an absolute rest frame to be as common-sensical as you do. Unfortunately, it isn't there.

A pair of photons emitted simultaneously from a point on a frame defines, a zero point reference for a perfect zero velocity FOR.

yes it is easy. Easier still is to measure the relative velocity of frame and photon as C + v or c - v depending on direction of the frame wrt the photon direction of motion.

Well, one can use the velocity of the emitted photns to calibrate the velocity measure re teh phoiton trajectories which comprise the rfame proper.

Then why doesn't this happen? Do you honestly believe that there's some kind of relativity conspiracy?

There's no absolute space or time.

All I said was that the emission point was invariant, from any physiocal intervention, once the point is defined. Yes, it is another way to describe absolute space and time. After all, that is the way it is.

So you say. Prove it.

Given the invariance of the SOL gives us absolute space and time. It is the measure of relative velocity of frame and photon that is mistaken by SRT. Look at the gedanken, the measurements of the SOL are wrt the invariant point of emission of two photons moving in opposite directions. Even one emitted photon defines a FOR: there is a zero point and a trajectory line both invariant spatially.

You haven't defined where this zero point is. You don't want it to be in the rod frame, so you put it in the embankment frame. What's your justification for this?

FYI the expression c- v is a measure of the difference in speeds of c and the frame, it is not a measurement of the SOL less than c. Also, c + V does not grant the SOL values > c it merely reflects the measured relative velocity of frame and photon moving in oppposite directions wrt each other. What is wrong with this?

Wrt. the original thought experiment of this thread, it violates the basic assumption. It doesn't say, "speed of light wrt. absolute space", it says that the speed of light is constant regardless of measurement frame. Hence, as viewed from the rod frame, the speed of light is c with respect to the frame, and in the embankment frame the speed of light is also c with respect to the frame. What is so difficult about this that you cannot grasp it?

No, if you deny that the emitted photons define an invariant point in space you have failed. If you cannot see that the trajectories of the emitted photons define an invariant straight line then you have failed. Someone told you to deny absolute space time reality under any reply or attack which is what you do with slavish obedienece. You fear even to hypothecise something anathemic to your SRT.

Again, I have failed if I don't accept absolute time and space.

Well, I don't. Not in the thought experiment, and not in reality.

The point of emission and the projected trajectory of the photons is the frame. Don't you get it yet?

I do, I just don't agree. Here's your argument in short:

1. The emission point is static in absolute space.
2. Only in absolute space is the SOL constant and isotropic.
3. Therefore the light arrives at L and R at different times.
4. Therefore the clocks read different times.

I don't agree with 1. because no such frame is evident, but if you want an extra frame, you're free to have it.
2. violates the basic assumption of the thought experiment.
3. should have an "as viewed from the absolute frame" tacked onto it.
4. only works if you accept 2. and I don't.

In the context of the original thought experiment your analysis doesn't work. In the context of reality, experiment proves you wrong.

What do you object to when the photons are emitted, that they aren't moving at the speed of c wrt the emission point? Is this what you are saying?

Of course not. But I am saying that you're not justified in preferring one frame over another, when looking at the emission point, and canonising the view from that particular frame as the true view of the universe. That the clocks should read different times is a direct contradiction with this basic assumption of the thought experiment, as James R shows perfectly well in the original post.

The universe sure appears to be Newtonian to me.

Then you seem to have missed a hundred years of physics. Pity.​

 

[Quantum Quack]

Why?

I'm asking you where the absolute rest frame is. If you claim that there's some "memory" of relative acceleration, then what that relative acceleration was originally with respect to, is a very reasonable question.

Please don't get hysterical. I find an absolute rest frame to be as common-sensical as you do. Unfortunately, it isn't there.

Then why doesn't this happen? Do you honestly believe that there's some kind of relativity conspiracy?

There's no absolute space or time.

So you say. Prove it.

You haven't defined where this zero point is. You don't want it to be in the rod frame, so you put it in the embankment frame. What's your justification for this?

Wrt. the original thought experiment of this thread, it violates the basic assumption. It doesn't say, "speed of light wrt. absolute space", it says that the speed of light is constant regardless of measurement frame. Hence, as viewed from the rod frame, the speed of light is c with respect to the frame, and in the embankment frame the speed of light is also c with respect to the frame. What is so difficult about this that you cannot grasp it?

Again, I have failed if I don't accept absolute time and space.

Well, I don't. Not in the thought experiment, and not in reality.

I do, I just don't agree. Here's your argument in short:

1. The emission point is static in absolute space.
2. Only in absolute space is the SOL constant and isotropic.
3. Therefore the light arrives at L and R at different times.
4. Therefore the clocks read different times.

I don't agree with 1. because no such frame is evident, but if you want an extra frame, you're free to have it.
2. violates the basic assumption of the thought experiment.
3. should have an "as viewed from the absolute frame" tacked onto it.
4. only works if you accept 2. and I don't.

In the context of the original thought experiment your analysis doesn't work. In the context of reality, experiment proves you wrong.

Of course not. But I am saying that you're not justified in preferring one frame over another, when looking at the emission point, and canonising the view from that particular frame as the true view of the universe. That the clocks should read different times is a direct contradiction with this basic assumption of the thought experiment, as James R shows perfectly well in the original post.

Then you seem to have missed a hundred years of physics. Pity.

I think what Geist is referring to when he talks of absolute space is space filled with photons that all exist in the same moment, thus absolute space does exist and it is constantly changing at the rate of all the photons movement which is 'c'.

Thus absolute space is changing at 'c'.
Because we are co-moving with this change we are at rest relative to the photon. we just travel the distance on the spot instead of moving in a straight line. Although sometimes we do move in a straight line as well as on the spot which is why we have dilation and length contraction.

Now the question of non -simultaneity is something yet to be proven. It is possible I guess but that isn't proof.

Just because a photon doesn't hit an object simultaneously due to length and dilation reasons does not make the photon non-simultaneous with all the other photons that exist. in fact invariance requires that all photons co-exist in the same moment. if not invariance fails.

Given the fact that a photon can not be seen as a 3 dimensional object how is it possible to prove that light photons do not exist in the same moment?

thus space is absolute and constantly changing at the same universal rate of 'c'

You ask Geist to prove the existence of absolute space yet SRT uses it all the time. [just that they don't call it the same thing]

 

[Quantum Quack]

when you look up at the stars at night or at any other time you see space and is that space full of photons all moving at v=c?
Can this not be considered as absolute space that is constantly changing at the rate of the photon?
In fact can space change at a rate any slower or faster than the photon?

For E = mc^2 to be universal in application the invariance of light thus the NOW must be true.

 

[MacM]

Why?

Maybe because it is prohibited by the same theory that uses it. Kinda neat how a theory can prohibit something and then use the same basic concept isn't it?

I'm asking you where the absolute rest frame is. If you claim that there's some "memory" of relative acceleration, then what that relative acceleration was originally with respect to, is a very reasonable question.

And the Big Bang would be a very reasonable answer.

Please don't get hysterical. I find an absolute rest frame to be as common-sensical as you do. Unfortunately, it isn't there.

Suppose I say it is, prove it isn't. Ever hear the very true "Absence of Evidence is not Evidence of Absence"?

Then why doesn't this happen? Do you honestly believe that there's some kind of relativity conspiracy?

There's no absolute space or time.

It may not be a conspiracy since that term requires planning and coordination with intent to do harm. But our education system coupled with extreme bias of the generation now in charge of the majority of employers and the resources (money, labs, etc) makes it fool hardy to speak out with any objection right or wrong against Einstein.

That fact is displayed here on a daily basis with the personal attacks by the professionals, just noitce how they not only trat non-professionals but their conter parts when such equally educated person suddenly realises or comes to believe as we do that there are inconsistancies in the theory.

They too are immediately referred to as quack, crackpot, etc, with no basis other than the bias that anybody that disagrees must be a crackpot. It is absoulte blind faith that dominates the themes of relativity.

So you say. Prove it.

Not a very conviencing reply. Do you have any proof supporting your view or do you just mimic others?

You haven't defined where this zero point is. You don't want it to be in the rod frame, so you put it in the embankment frame. What's your justification for this?

What is your justification for claiming it is non-existant? Because you can't see it? When did you last see a Quark, Strings, Dark Matter or Dark Energy?

Wrt. the original thought experiment of this thread, it violates the basic assumption. It doesn't say, "speed of light wrt. absolute space", it says that the speed of light is constant regardless of measurement frame. Hence, as viewed from the rod frame, the speed of light is c with respect to the frame, and in the embankment frame the speed of light is also c with respect to the frame. What is so difficult about this that you cannot grasp it?

I haven't seen him claim otherwise. How does this answer his gendanken?

Again, I have failed if I don't accept absolute time and space.

Well, I don't. Not in the thought experiment, and not in reality.

Then you have failed and because you either lack vision, courage or both. Which is it?

I do, I just don't agree. Here's your argument in short:

1. The emission point is static in absolute space.
2. Only in absolute space is the SOL constant and isotropic.
3. Therefore the light arrives at L and R at different times.
4. Therefore the clocks read different times.

I don't agree with 1. because no such frame is evident, but if you want an extra frame, you're free to have it.

I do believe this view is consistant with the invariance advocated by SRT is it not? Show how it isn't if you insist it is not a valid view.

2. violates the basic assumption of the thought experiment.

How so?

3. should have an "as viewed from the absolute frame" tacked onto it.

You are claiming that light arrives at L and R simultaneously?

4. only works if you accept 2. and I don't.

Not accepting something is every persons perogative. Not justifying your view or relying on rhetoric, fiat, innuendo, etc., is quackery.

In the context of the original thought experiment your analysis doesn't work. In the context of reality, experiment proves you wrong.

In what respect?

Of course not. But I am saying that you're not justified in preferring one frame over another, when looking at the emission point, and canonising the view from that particular frame as the true view of the universe. That the clocks should read different times is a direct contradiction with this basic assumption of the thought experiment, as James R shows perfectly well in the original post.

Not so.

Then you seem to have missed a hundred years of physics. Pity.

The pity is that SRT'ists are incapable of independant thought.

The only thing clearly missed for 100 years is any proof or evidence supporting SRT's reciprocity of time dilation.

 

[john smith]

Not accepting something is every persons perogative.

wel it seems to be yours anyway

 

[funkstar]

Maybe because it is prohibited by the same theory that uses it. Kinda neat how a theory can prohibit something and then use the same basic concept isn't it?

Explain how it is prohibited.

And the Big Bang would be a very reasonable answer.

Really? You do know that the Big Bang theory entails that it started, literally, right here? And that it also, literally, started everywhere else?

So, no, that wouldn't be a reasonable answer.

Suppose I say it is, prove it isn't. Ever hear the very true "Absence of Evidence is not Evidence of Absence"?

Yes. From creationists.

Also, in this case we have an astonishing body of evidence against it.

It may not be a conspiracy since that term requires planning and coordination with intent to do harm. But our education system coupled with extreme bias of the generation now in charge of the majority of employers and the resources (money, labs, etc) makes it fool hardy to speak out with any objection right or wrong against Einstein.

That fact is displayed here on a daily basis with the personal attacks by the professionals, just noitce how they not only trat non-professionals but their conter parts when such equally educated person suddenly realises or comes to believe as we do that there are inconsistancies in the theory.

They too are immediately referred to as quack, crackpot, etc, with no basis other than the bias that anybody that disagrees must be a crackpot. It is absoulte blind faith that dominates the themes of relativity.

So it's all brainwashing, instead. Fascinating.

Not a very conviencing reply. Do you have any proof supporting your view or do you just mimic others?

In the context of the original thought experiment what I'm saying is obviously correct. As for reality, I'm sure you're aware of the evidence for the invariance principle. If not, there's a small list here

What is your justification for claiming it is non-existant? Because you can't see it? When did you last see a Quark, Strings, Dark Matter or Dark Energy?

My justification is the invariance principle. It precludes an absolute space and time - in fact, the very purpose of this thought experiment is to show that such a thing is an illusion based on nothing more than the invariance principle.

I haven't seen him claim otherwise.

Then you must have missed this gem:

In the experiment in the figure all time measurements are wrt the moving clocks.

Which flatly contradicts the invariance principle.

How does this answer his gendanken?

It explains specifically where he is wrong and why.

I do believe this view is consistant with the invariance advocated by SRT is it not? Show how it isn't if you insist it is not a valid view.

Did you not see that I granted him an extra frame if he wanted it?

How so?

Because if the rod clocks read different times, then light has taken different rod time to cover the same distance in the rod frame. This directly contradicts the assumption of constancy of light speed in all frames! Is it somehow hard to grasp why? It's very basic, yet it seems to me that we're flogging the horse, here...

You are claiming that light arrives at L and R simultaneously?

As viewed from the rod frame, yes. As viewed from the embankment frame, no. Did you read the original post at all? Do you even understand what the invariance principle states?

Not accepting something is every persons perogative. Not justifying your view or relying on rhetoric, fiat, innuendo, etc., is quackery.

Which is why asking us to prove relativistic effects without the basic assumptions that make us able to present them in a consistent manner is... well... stupid. James R's thought experiment assumes the invariance principle. geistkiesel claimes to refute his analysis based on an assumption of absolute space and time. Do you (both you and geistkiesel) see why this doesn't work?

Hint: The invariance principle and absolute space and time are incompatible.

In what respect?

Both in the direct sense that no anisotropy of light speed has ever been found, and that prediction based on theories that incorporate the invariance principle are far closer to observation than those not incorporating them. For instance, gravitational bending of radio waves by the sun matches incredibly well with GR's predictions.

Not so.

Explain where James R goes wrong, then.

The pity is that SRT'ists are incapable of independant thought.

Nice. You want to go back to a Newtonian universe, so we're reactionary.

The only thing clearly missed for 100 years is any proof or evidence supporting SRT's reciprocity of time dilation.

Those atomic clock are faulty, then?