Time dilation - a global hoax?

[[Tycho?]]

After correcting for GR effects and effects due to acceleration' date=' right? Not quite model independent, is it? Once you know what it is that you are looking for in an experiment, it is hard not to find it. All experimentalists struggle with this bias problem. The greater ones recognize it and bend over backwards to maintain the highest levels of scientific integrity, but even they are not immune to it.

 

[/quote']

 

WHAT THE HELL ARE YOU EVEN ARGUEING? Do you know how hard people tried to disprove SR when it was first published? Its not like it was accepted with open arms, it tooks many years and many, many experiments. Attempts to prove SR succeeded, attempts to disprove it failed.

 

Why the hell are you talking about model independant? Why does this even matter? SR works in every way thats ever been tested. It has defied attempts to disprove it. It is a very succesfull theory. dot dot dot. So why are are you talking about biases and stuff? If your argument is that you cannot prove any theory totally you are correct.

 

But SR works! And, responding to the title of this thread, time dilation exists, exactly as it is predicted by theory. Time dilation is hence not a "global hoax" Thread done.

[Mowgli]

There are only two assumptions that go into SR. One is that the laws of physics are valid in inertial frames' date=' and the other is that c is a constant. The latter basically falls out of Maxwell's equations. Since relativity and E&M seem to work pretty well, I'd say that a high degree of confidence is justified.

[/quote']

You missed out the assumption of the homegeneity of space and time from which the lineary of the coordinate transformation arises, along with the assertion that only receding frames of reference need to be considered. Another assumption/assertion is the redefinition of simultaneity. My understanding is that the reason for the light speed barrier comes about because SR treats only receding frames.

Being unorthodox is not' date=' in and of itself, sufficient justification. But you have spent all of your time complaining about how SR is religious orthodoxy, but [b']you haven't presented an alternative[/b]. So, until you do so, stop accusing people of actions and attitudes that they haven't demonstrated.

Don't get upset about accusations of faith, swansont; after all this is a forum that routinely accuses people of ignorance and lack of education and whatnot if they dare to question the mainstream!

Anyways, if you are really interested in the alternative, it is attached. It concentrates on two rather poorly understood astrophysical pheneomena, and finds a simple explanation for them outside the assumptions and consequences of SR. Admittedly, it doesn't analyze and explain every experimental support in a new framework, which is not something one can do while holding on to a day job to pay the bills.

unreal-article.pdf

[kkris1]

Hi Tannin,

Thanks for your great contribution. But I still need some clarification:

In first diagram the vertical ray will hit the ceiling of the spacecraft earlier then slanted one. But from stationary observer point of view vertical ray becomes slanted forward and slanted backwards becomes vertical.Still the events order should be the same as inside spaceship. Therefore from stationary observer's point of view the slanted ray will hit the ceiling first, thus covering longer distance in shorter time.

Could you explain why order of these events (rays hitting the ceiling) in your second diagram is reversed in your description?

[swansont]

Don't get upset about accusations of faith' date=' swansont; after all this is a forum that routinely accuses people of ignorance and lack of education and whatnot if they dare to question the mainstream!

[/quote']

 

People are accused of ignorance when they demonstrate it, like when they criticize a well-established theory while showing they don't understand it.

[Mowgli]

People are accused of ignorance when they demonstrate it, like when they criticize a well-established theory while showing they don't understand it.

Likewise, blind faith is indicated when people accept whatever theory they are taught without ever examining the assumptions that go into making the theory.

 

There was one poster, supporting SR using rather colorful language, who couldn't understand why pure SR time dilation is impossible to measure. Wonder why you wouldn't accuse him of lack of understanding -- because he supports your faith? (Apologies to the poster for this uncharitable use of his post.)

 

Honestly, do we have to go down this road? I can happily accept and live with my ignorance. What does it matter that space contracts and time dilates when I can't even define what space and time are? Like someone far wiser than you and me pointed out, "Space and time are modes by which we think, not conditions in which we live."

[bascule]

What does it matter that space contracts and time dilates when I can't even define what space and time are? Like someone far wiser than you and me pointed out, "Space and time are modes by which we think, not conditions in which we live."

 

In context, Einstein meant that space and time are not independent of each other, and the way we measure time is completely artificial. His sentiment is pretty much completely opposite of your defeatist position.

[Mowgli]

In context, Einstein meant that space and time are not independent of each other, and the way we measure time is completely artificial. His sentiment is pretty much completely opposite of your defeatist position.

I think what Einstein meant was that space and time were cognitive constructs, phenomenal or perceptual reality rather than the noumenal cause behind it.

 

Would you happen to have the context in which AE said it so that what he meant is clear? If so, could you post it? If not, wonder why you didn't have a qualifier like "I think Einstein meant..." or "In my opinion..."

[Mowgli]

'']Attempts to prove SR succeeded, attempts to disprove it failed.

Attempts to disprove SR did not fail, they got much less press. Like the links to the two challenges I posted in this thread, which went unaswered. The usual response from the experts is that they have neither the time nor the inclination to figure out what the challenger's mistake is. But one of the challenges actually offered $50,000 to make it worth their time!

']

Why the hell are you talking about model independant?

Assuming this is not a rhetorical question -- by model independent I meant an experiment where extra corrections were not made to the measurements' date=' and where the undilated time duration was known accurately and independently.

']

But SR works! And, responding to the title of this thread, time dilation exists, exactly as it is predicted by theory. Time dilation is hence not a "global hoax" Thread done.

To recap the thread history, I was one of the first ones to point out to the original poster that SR was mathematically consistent. ie, if he accepted the coordinate transformation in SR, there was no way he was going to find an inconsistency with its predictions. The orginal poster got a little upset and complained of a religious attitute when it came to SR. I agreed with him and told him that there was a bit of religiousness in the way in which modern physics is taught, where criticism is not tolerated. This criticism (of the teaching methods of modern physics) landed me in all kinds of trouble. Paradoxically perhaps, the trouble I got in is proof enough to the impatience with which mainstream physics treats criticism. IMHO, physics will be better served when the experts are more inclined to periodically reexamine the basic assumptions and interpretations of its theories. Then again, it is only my opinion; experts should and will do what they damn well please, as one of them rightly pointed out. And finally, I don't think time dilation is a global hoax either. I do have some concerns about its origin, interpretation and magnitude. If you would like to know why, please take look at my article that I posted earlier.

[swansont]

I think what Einstein meant was that space and time were cognitive constructs' date=' phenomenal or perceptual reality rather than the noumenal cause behind it.

 

Would you happen to have the context in which AE said it so that what he meant is clear? If so, could you post it? If not, wonder why you didn't have a qualifier like "I think Einstein meant..." or "In my opinion..."[/quote']

 

Einstein's discussion of physics is what matters; what he said applies to that and is accepted because it observed to hold, not because Einstein said it. Anything Einstein might have said on the topic of perception is immaterial to the discussion.

[swansont]

Likewise' date=' blind faith is indicated when people accept whatever theory they are taught without ever examining the assumptions that go into making the theory.

 

There was one poster, supporting SR using rather colorful language, who couldn't understand why pure SR time dilation is impossible to measure. Wonder why you wouldn't accuse him of lack of understanding -- because he supports your faith? (Apologies to the poster for this uncharitable use of his post.)[/quote']

 

I don't know what post to which you refer.

 

Honestly, do we have to go down this road? I can happily accept and live with my ignorance. What does it matter that space contracts and time dilates when I can't even define what space and time are? Like someone far wiser than you and me pointed out, "Space and time are modes by which we think, not conditions in which we live."

 

No, "we" don't have to go down this road. Your participation here is purely voluntary, but also, this is the physics forum, not the philosophy one.

[Tannin]

For those who are interested what is SR explanation of the original kkris1 question.

In the posts #5 and #39 I´ve shown the necessary diagrams and formulas. But kkris1 was (justly) not satisfied and in his post #53 he asks why the order of hitting the ceiling by vertical and slanted rays for stationary and moving observer is reversed (diagram in #39).

I think this question is related to the fascinating point in SR about the order of events.

Let´s begin with the simpler example.

Borrowing the diagram from Landau, Lifshitz - Theory of fields - par.1.

The frame X´Y´Z´ is moving right along the X-axis with some constant velocity V. From the point A two signals (light flashes) are sent in opposite directions. Because the velocity of light is equal in every inertial frame, they will reach points B and C (equidistant from A) simultaneously in the moving frame X´Y´Z´. But the same two events are not simultaneous in the stationary frame XYZ. Indeed point B moves toward the flash, while the point C runs away from the flash. Thus in the stationary frame XYZ signal will arrive to the point B before he reaches the point C - two events are not simultaneous now.

Exactly, the same thing happens in kkris1 thought experiment. I bring here again the diagram for easier reference

In the moving frame slanted ray hits the ceiling after the vertical ray. Transition to the stationary frame brings about reversal of the order of the events and now ¨originally vertical in the moving frame¨"ray hits the ceiling after the ¨originally slanted ray¨. While choosing proper frame velocity we can make both events to happen simultaneously.

Using formula [math]\cos{\theta}=\frac{\cos{\theta^\prime}+\frac{V}{c}}{1+\frac{V}{c}\cos{\theta^\prime}}[/math] and substituting [math]\theta=90^\circ[/math] and [math]\theta^\prime=67.5^\prime[/math], we have V=0.38c. The angle 67.5 comes from the requirement that both rays will make equal angle with the vertical direction while preserving 45 degrees between them (read post #39). In this case both rays will hit the ceiling simultaneously and this will happen after [math]\frac{h}{c \sin{67.5}}[/math] seconds.

The proper name offered by SR for these two events (a ray hits the ceiling) are ¨spacelike¨ (Landau, Lifshitz - par. 2)

Because I am not an expert in SR, I invite the experts to check my calculations and point out the errors.

Also, I would like to remind that there is no such thing as time dilation for the light rays - their world lines are always straight.

[Mowgli]

But you have spent all of your time complaining about how SR is religious orthodoxy, but you haven't presented an alternative[/b']. So, until you do so, stop accusing people of actions and attitudes that they haven't demonstrated.

Okay, just for the record, I did present my alternative a few weeks ago.

[attach]1380[/attach]

[gib65]

Sorry for the late reply, but I just read the OP's challenge and, even after reading over this entire thread (well, perusing), I still don't get it. I read Severian's explanation of proper time, but it still seems there would be a paradox. I don't want to challenge SR, so I ask this question with the understanding that it is my lack of understanding that's the problem, and I'd be grateful to anyone who can give me a clear answer.

 

First off, let me simplify the scenario - instead of light impulses reflecting off mirrors, let's just say they take a one-way trip - that is, they travel from the source, hit the ceiling and that's it. We still have the same paradox but without the change of direction the light would take half way through their trip (so GR can't compensate). Also, let's call the travelling observer Tom and the stationary observer Sam. Let's call the light impulse that Tom sees as moving vertically V and the one he sees as moving diagonally as D.

 

Now to Severian's explanation. Since the time it takes for V to complete its trip, as measured by Tom's clock, is the proper time [math]\tau[/math], that makes the time measured by Sam's clock for V the dilated time [math]t[/math]. I know, from past examples, that Sam's measurement is the greater one, so I assume that [math]\gamma[/math] is greater than 1. Now, in regards to D, if what Severian says is true, then it must be Sam's measurement that is the proper time [math]\tau[/math], and since [math]\gamma[/math] is greater than 1, the dilated time [math]t[/math], which must be what Tom measures, is greater than [math]\tau[/math]. Also note that the time that Tom measures for V and the time Sam measures for D must be the same - that's what it means for light to travel 300,000 Km/s independently of the speed of the observer. So if you follow this to its logical conclusion, Tom observes V finishing its trip sooner than D, while Sam observes V finishing its trip later than D.

 

It seems to me that the paradox still exists. But as I said, I'm betting the farm that it's my misunderstanding. But I would like to know where I'm going wrong.

[swansont]

Severian explained that the proper time has to be measured at a particular point in one frame of reference. The one-way light path does not fulfill this requirement. (in fact there is a whole subset of relativity arguments about the "one-way" speed of light vs "round-trip" speed of light)

[gib65]

Severian explained that the proper time has to be measured at a particular point in one frame of reference. The one-way light path does not fulfill this requirement. (in fact there is a whole subset of relativity arguments about the "one-way" speed of light vs "round-trip" speed of light)

 

Well, okay, make it a round-trip then. Isn't there still a paradox?

[swansont]

Well, okay, make it a round-trip then. Isn't there still a paradox?

 

A paradox apparently occurs only because you have an expectation of the order of events, but that isn't an absolute. The order of events depends on your reference frame.

[gib65]

A paradox apparently occurs only because you have an expectation of the order of events, but that isn't an absolute. The order of events depends on your reference frame.

 

You must be talking about the relativity of simultaneity, right? I hope you don't mind if I drag this on a little further - I'm still confused .

 

I can understand what Einstein meant by the relativity of simultaneity, but I can't understand when it is used to reverse the order of "before" and "after". That is, for Tom, V completes its trip before D, but for Sam, D completes its trip before V.

 

Let me make the scenario a little more complicated. Suppose Tom is in a jettison pod that is equidistant between the two light sources. On the pod is a self-destruct switch that, when flicked sends signals, at the same time, to both light source telling them to emit a light impulse. When the light impulse of V completes its round-trip, it triggers a light sensitive device that jettisons the pod. When the light impulse of D completes its round-trip, it triggers a light sensitive device that explodes the ship (it's a really, really large ship, so D takes a lot more time than V to complete its trip - enough time for the pod to fully jettison).

 

So now the question is, does Tom survive or not? From the point of view of Tom's reference frame, he must survive, but from Sam's, he will not.

 

Again, sorry if I'm annoying the experts, but when I encounter a paradox (or pseudo-paradox) like this, my mind won't rest until I get an answer.

[swansont]

I'm not sure you gain by making the situation more complicated when the simpler system is still causing issues, but for a situation like a projectile hitting a target, if it happens in one frame it has to happen in all frames. The issues with simultaneity revolve around events that are separated in space.

 

(I'll try and revisit this in more detail when I have the time.)

[swansont]

The problem with the scenarios described, I think, is that you are assuming instantaneous knowledge of the light pulses, and that violates relativity. That is, you have two light pulses, and you are measuring the time it takes for them to travel some path. But because you have not "closed the loop" on some of them, you must also account for how long it takes for the information to get to you that the pulse has completed its travel. That's the problem with the angled light pulse (rest frame) — you can either know when the pulse left or arrived, by standing next to that point, but you can't know both. The information about one or the other can only travel at c. The vertical pulse has the same departure and arrival point, and avoids this problem.

 

So the paradox is that you have implicitly assumed instantaneous travel of information.

[gib65]

So let me see if I understand. Sam, who measures D, can know when D has completed its trip causing the ship to explode, but he can't know when V has completed its trip causing Tom to be jettisoned. Meanwhile, Tom can know hen V had completed its trip causing him to be jettisoned, but not when D has completed its trip causing the ship to explode. So neither one can say which event happened before the other. Is that correct?

 

Is there any way of predicting the outcome at all? I mean, eventually, Tom and Sam will either rondezvous or not. Is there any way of predicted beforehand whether this can happen (Tom survives) or not (Tom dies)?

[swansont]

I haven't diagrammed your Tom v Sam scenario yet, but in it you describe round-trip light pulses, so that's different than the original system described by the OP.

 

If an event happens in one frame, it happens in all frames. It is the ordering of events that can be mixed, not the occurrence of the events.

 

edit: I suspect that in your scenario, the location of the explosive in relation to the trigger is the missing information, and the apparent paradox occurs because you assume the entire ship explodes instantaneously, or the signal to trigger it does. In Tom's frame, he may eject before the explosion, and in Sam's after, but the explosion cannot have gotten to Tom's location before he ejects, in any observer's frame. So Tom thinks the escape is no big deal, and Sam observes a Hollywood movie-style escape.

[gib65]

I suspect that in your scenario, the location of the explosive in relation to the trigger is the missing information, and the apparent paradox occurs because you assume the entire ship explodes instantaneously, or the signal to trigger it does.

 

* slaps self on forehead * D'Oh! Of course! It would take time for such a long ship, wouldn't it.

 

So Tom thinks the escape is no big deal' date=' and Sam observes a Hollywood movie-style escape.[/quote']

 

I love that! Can we add music to the scenario?

[swansont]

I love that! Can we add music to the scenario?

 

 

In space, no one can hear you jam.

[gib65]

In space, no one can hear you jam.

 

That's BS! It happens all the time in Star Wars.