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Relativity, a theory of information?

  1. Apr 8, 2012 #1
    I know that the relativistic effects really do happen, such as time dilation and length contraction. However both frames of references predict these effects in the other frame of reference. It is said that these effects really happen in both of them, due to relativity of simultaneity. The thing is that I don't really believe in relativity of simultaneity. Isn't it possible that only one or none of the frames of references make the right prediction. The other frames prediction is then wrong? The measurements between each frames are different events from the ones being measured.

    Consider this example. There is observer A on the ground and observer B on a train. Observer A sees two lightening bolts strike the train at both sides simultaneously. Observer A sees that observer B observes the light from the front lightening bolt first, because he travels towards it. Observer B sees that the front lightening bolt strikes at first and then the one behind. He predicts that observer A sees them simultaneously because the lightening bolt at the back strikes when the light from the front bolt is at the same position. So the question is, why aren't just one or none of these predictions the right one according to more absolute properties of time and space?

    In the end when two observers arrive at an equal frame of reference, it is only one of them who shows relativistic effects.
     
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  3. Apr 8, 2012 #2

    Dale

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    Yes, it is possible. The problem is identifying the right frame, it looks just like all of the other ones and behaves as though it doesn't exist.
     
  4. Apr 8, 2012 #3
    The 'right' frame ends up being the one you are in. The other frames are right for those observers. The weird thing is that all are correct, yet generally different. One of the other frames is 'right' for you when you are in that frame.

    Simultaneity is a tricky 'dude' when time and distance are not agreed upon by different observers, yet the speed of light is agreed upon by different observers....that still seems 'impossible' to me, but it's what we observe, so that's 'reality'.....consistently inconsistent!!!! It simply refuses to conform to everyday 'logic'...
     
  5. Apr 8, 2012 #4
    To the degree that the data one receives (magnitude and sequence) is dependent on one's frame of reference, relativity might very well be characterized as a theory of information, not an existential theory of reality.

    An existential theory would require absolute positions, magnitudes, and sequences that would ultimately be comprehensive, complete, and consistent for any measures from each frame of reference, and across all possible frames of reference. From an existential perspective, it does seem peculiar that each observer views his local measures as normal but requires relativistic transforms to interpret measures from a distance or at high speed. The "firm fundamental foundation" aspect of an existential concept of physical reality is just not present in relativity measures.

    The sense that ultimate reality must be at least logically existential is what I think has motivated analysis of mathematical structures where comprehensive, complete, and consistent entities can be found that display invariant attributes.
     
  6. Apr 9, 2012 #5

    ghwellsjr

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    I don't see how your example illustrates your reason to disbelieve relativity of simultaneity or how it illustrates conflicts in measurements between frames since both observers agree as to what the observer sees and predicts. What am I missing?
     
  7. Apr 9, 2012 #6

    ghwellsjr

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    Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?
     
  8. Apr 9, 2012 #7
    I didn't give any reason yet which explains why I disbelieve in relativity of simultaneity. I was just trying to illustrate how it is possible that there could perhaps be an absolute frame of reference? What each frame predicts is not reality, it is just predictions after all.

    Also, it seems as though they have different conclusions as well. In the given example, both of them believe that it is the other person who moves and have relativistic effects, leading to different predictions of sequences of events.

    The reason I don't believe in relativity of simultaneity is because I think it can be a bit ignorant to only consider what measurements tells us, without taking into account that what we see is actually based on an objective existence. Measurements are nothing but a seperate prediction of a true event. What about entanglement? This tells us how particles relate to each other simultaneously regardless of speed.
     
  9. Apr 9, 2012 #8

    Dale

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    The problem is that the only "objective existence" that is compatible with the experimental evidence is a type that is consistent with there being no "objective existence". In other words, it doesn't matter if there is one "true frame", it doesn't do anything, so you can ignore it if you want to. Of course, if it comforts you to believe that it is there, then you can imagine it is there, somewhere, lurking in the shadows, completely hidden and impotent. But if you don't want to be bothered with it then you will not get anything wrong by ignoring it either.
     
  10. Apr 9, 2012 #9
    Dalespam's retort is well said.

    for the part in bold;
    "Relate" to each other in the same sense I "relate" to my brother. And that relation exists no matter the spacial seperation. Also regardless of speed. :rolleyes:

    What does "entanglement" mean to you faen?
     
  11. Apr 9, 2012 #10
    You are questioning this?
     
  12. Apr 9, 2012 #11

    ghwellsjr

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    Yes, the OP didn't give an example, can you?
     
  13. Apr 9, 2012 #12
    Originally Posted by ghwellsjr View Post


    Not sure where your going here but how about:
    Simultaneous light flashes are set off on a train [inertial of course and by train clocks]

    In that frame the sequence is simultaneous and the magnitudes of the light spheres are isotropically uniform only varying equally with distance from the sources. No Doppler shift.

    In the ground frame they are sequential. The observed magnitude is location dependent and does not vary consistently with distance from the source . There is position dependent Doppler shift.

    Perhaps this isn't what you are talking about at all, so maybe you could give an example of what you mean.
     
  14. Apr 10, 2012 #13

    ghwellsjr

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    This isn't what the OP nor what bahamagreen were talking about. They were talking about what an observer sees or measures. You didn't have any observers, did you? Can you put in some observers and demonstrate how what they see or measure is different in the two frames?
     
  15. Apr 10, 2012 #14
    Sorry I thought that observers were implicit as the factors mentioned would apply through out the frames.
    So a midpoint train observer would see the flashes as simultaneous and equal in magnitude/brightness and without Doppler shift , other train observers would measure the magnitude as a consistent function of their distance from the sources. No Doppler
    A midpoint ground observer would see the rear flash first ,measure it as of lesser magnitude than the front flash even though equidistant and would see the rear blue shifted and the front red shifted.
    Another ground observer behind the train but at an equal distance from the rear flash as the mid observer would measure it as having a lesser magnitude and being red shifted . No consistency of the ratio of distance to measured magnitude.Etc,etc........
    But maybe I am missing something here and this is still not what you are talking about???
    BTW I thought what bahamagreen was talking about was exactly this and thought his view was lucid and to the point.
     
    Last edited: Apr 10, 2012
  16. Apr 10, 2012 #15

    ghwellsjr

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    Now you have a bunch of different observers who all see and measure different things as you described but no mention of which frame(s) you used to determine what they each see and measure. Are you suggesting that if you consider all these observers using the ground frame, they make one set of observations and measurements but if you consider them using the train frame they each make a different set of observations and measurements?

    For instance, take your first observer, if you analyzed what he sees using the ground frame (or any other frame), would you conclude that he sees the flashes at different times or with different magnitudes or with a Doppler shift? Or any of the other observers analyzed from any other frame?
     
  17. Apr 10, 2012 #16

    ghwellsjr

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    Can you be specific about what the characteristics of this absolute frame are? Einstein's Frames of Reference all have an origin (where t=0, x=0, y=0 and z=0). Would this be true of the absolute frame?
    If two frames were identical in every respect except that they had different origins, this would result in them having different conclusions, wouldn't it? Would that be a reason to discount the concept of frames?
    Isn't what we see a form of measurement? What if we had a precision, calibrated video camera to make measurements, would you discount that? Aren't all measurements just as much objective existence as what we see?
     
  18. Apr 10, 2012 #17
    OK finally I see what your talking about and of course the answer is no. I got from the OP and bahamagreen that the idea was hypothetical direct observation and measurement , not analyzation or calculation which can be done solely from any frame , even this one :-),,,, on a good night.
     
  19. Apr 10, 2012 #18
    I suppose I am trying to get an idea of what space really is. Assuming that one frame is the "right one" makes it possible to imagine an existing mathematical construct of space. Otherwise I really can't think of any mathematical construct of space which is consistent with that all the relativistic "predictions" are true for all frames of references. At least not if I don't believe in relativity of simultaneity.

    No not that alone. I guess it's for the reason mentioned above, and sceptisism towards relativity of simultaneity.

    Measurements are evaluated subjectively. Even sight. Thus they are not objective existence. Also the measurements themselves are different events from those measured.
     
  20. Apr 10, 2012 #19

    ghwellsjr

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    In your first post, you said that "Observer A sees two lightening bolts strike the train at both sides simultaneously". I took that literally as an objective truth. Now you are saying that I was misled, that I should have taken it subjectively, but that just makes it impossible for me to have any idea what you meant. If we can't trust our measurements, then there is no hope of making any sense out of anything. With this level of skepticism, I wonder why you even consider such a thing as an absolute frame or why you are even "trying to get an idea of what space really is".
     
  21. Apr 10, 2012 #20
    Maybe it was misleading that I said that it is subjective. I do still consider it as information related to the objective caused "somewhere" by objective reality, most likely by determined by the current models/theories we have. Perhaps it's just best to pretend that I didn't say anything about subjective in case it causes any confusion, sorry..

    When it comes to the lightening bolts they were measured by the frame of reference to strike simultaneously, but whether they truly did or not is still unknown to me, since perhaps it did not to an absolute/real frame of reference..
     
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