New Arguments In A Possible Proof That Negative Ageing Doesn't Occur In Special Relativity

Discussion in 'Physics & Math' started by Mike_Fontenot, Aug 7, 2021.

  1. Mike_Fontenot Registered Senior Member

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    A Possible Proof That Negative Ageing Doesn't Occur In Special Relativity

    Michael Leon Fontenot


    According to the CMIF (Co-Moving-Inertial Frames) simultaneity method, an observer (he) who accelerates in the direction away from a distant person (she) will conclude that she rapidly gets YOUNGER during his acceleration. But I think I may have found a counterexample that shows that such an accelerating observer does NOT conclude that.

    It is well-known that two stationary clocks at different positions in a gravitational field will run at different rates. The clock that is closer to the source of the gravitational field will run slower than the clock that is farther from the source of the field.

    Because of the equivalence principle, it is also true that if two clocks that are separated by a fixed distance "d" ly are both accelerated with a constant equal acceleration of "A" ly/y/y, the trailing clock runs slower than the leading clock, by the factor exp(Ad).

    So consider the following scenario:

    At some instant, the perpetually-inertial "home twin" (she) is 20 years old, and is holding a display that always shows her current age. Facing her is the "helper friend" (the "HF") of an observer (he) who is "d" ly away to her right. Both the HF and he are also 20 years old, and are stationary wrt her at that instant. Like her, he and the HF are each holding a display that always shows their current ages.

    Now, suppose that he and his helper then both start accelerating at a constant "A" ly/y/y toward the right. He knows that his helper friend (the HF) is then ageing at a constant rate that is slower than his own rate of ageing, by the factor exp(Ad).

    An instant later, his display shows the time 20 + epsilon_1, where epsilon_1 is a very small positive number. He knows that HF's display shows the time 20 + epsilon_2, where
    epsilon_2 = epsilon_1 / exp(Ad). Epsilon_2 is less than epsilon_1, but is also positive. She can still see HF's display (because HF has only moved an infinitesimal distance away from her, to her right). She will see that HF's display reads 20 + epsilon_1 / exp(Ad). And likewise, HF can still see her display. What does HF see on her display?
    Does HF see that she is now slightly younger than 20? No! It would clearly be absurd for someone essentially co-located with her to see her get younger. What HF would see her display reporting is that she was now some very small amount epsilon_3 OLDER that she was at the instant before the acceleration. HF then sends a message to him, telling him that she was 20 + epsilon_3 right then. When he receives that message, he then knows that her current age, when he was 20 + epsilon_1, was 20 + epsilon_3, which is greater than 20. So he KNOWS that she didn't get younger when he accelerated away from her. That contradicts what CMIF simultaneity says.

    In the above, I asked

    "What does HF see on her display?".

    And I answered

    "HF would see her display reporting that she was some very small amount epsilon_3 OLDER that she was at the instant before the acceleration."

    Since the above argument makes use of very small (unspecified) quantities, it could be argued that time delays due to the speed of light might also need to be taken into account when describing what the HF sees on her display.

    But I think any such concerns can be alleviated by pointing out that the separation "d" between him and her can be made arbitrarily large, and CMIF simultaneity says that the amount of negative ageing that occurs is proportional to their separation. Since the errors involved due to the finite speed of light between her and the HF are independent of the distance "d", those errors become negligible compared to the change in her displayed age seen by the HF, for sufficiently large "d".

    If the CMIF simultaneity method is incorrect, as the above proof contends, what is the alternative? I am aware of only a single alternative that (like the CMIF method) obeys the principle of causality. I describe that alternative in my paper, “A New Simultaneity Method for Accelerated Observers in Special Relativity”, on the viXra repository:

    http://viXra.org/abs/2106.0133

    I've put the above possible proof that there is no negative ageing (and thus that the CMIF simultaneity method can't be correct) on the viXra repository:

    http://viXra.org/abs/2106.0142

    There is another argument that shows that the HF ("Helper Friend") can't conclude that the home twin (she) is less than 20 years old when the HF is 20 + epsilon_2. We can require that she transmits NO light messages to him when she is 20 years old or younger. Suppose the HF receives a light message from her when he is 20 + epsilon_2 years old. By the requirement, she must have been older than 20 years old when she sent that message. When the HF receives that message, he knows that she must be older than when she sent the message, so she must definitely be older than 20 years old when the HF is 20+epsilon_2. Therefore, she did NOT get younger, according to him, when he accelerated away from her.

    A still simpler argument is that, if the HF ever concluded that she got younger when he accelerated away from her, he would be concluding that she was less than 20 years old at that instant of his acceleration. But the HF was co-located with her when she was less than 20, and he couldn't be two places a that same instant.

    It seems to me that, once the distant accelerating observer has a way to set up an array of clocks (with attending observers) that he can use to define his concept of "NOW" (analogous to how Einstein did it for perpetually-inertial observers), it becomes impossible for the home twin to age negatively, according to the distant accelerating observer. It's true that those clocks aren't synchronized as they are in the perpetually-inertial case, but they don't have to be, since the distant accelerating observer knows exactly how the rates of those clocks compare to his own clock.

    I suspect that the same type of argument can be used to show that the essentially instantaneous (positive) ageing of the home twin (according to the traveler who instantaneously changes his velocity) also cannot occur. If these arguments are correct, then the commonly-used CMIF (Co-Moving Inertial Frames) simultaneity method can't be correct.
     
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  3. DaveC426913 Valued Senior Member

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    :reported to have this appended to the existing thread living in the appropriate Alt Theories forum:
     
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  5. Mike_Fontenot Registered Senior Member

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    I just reported YOUR post. My posts are NOT about an alternative theory to special relativity. There are aspects of special relativity that are still (after more than 100 years) in disagreement, and those disagreements SHOULD be discussed in a forum on special relativity.
     
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  7. Neddy Bate Valued Senior Member

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    First of all, SR does not include gravity, which is curved spacetime. So you need to reformulate your whole argument to be in flat spacetime. The equivalence principle only gets you so far, and it is restricted to being local.

    That aside, surely you must agree that the CMIF method of SR simply means that even someone who is not inertial can adopt the same definition of simultaneity as a Co-Moving Inertial Frame (CMIF). There I said "of SR" to specifically remind you of flat spacetime, with no gravity.

    So, CMIF says that if the woman (SHE) is 40 years old currently in her own inertial rest frame, and if someone else (HE) has an instantaneous velocity of 0.00000 relative to her, then HE can simply agree that her current age is 40, regardless of the distance between the two of them. You can never prove that he could ever possibly be wrong in doing that, because he would only be doing the exact same thing that a person with a constant velocity of 0.00000 relative to her can do routinely in SR.

    Every time you try to beat this dead horse, I laugh. You want actual physicists to take seriously the idea that you are not sure whether or not SR might allow that she can be both 40 years old, and some other age, according to two people who have 0.000000 relative velocity between them, and are even both located in the same place, with no gravity! It is, has always been, and continues to be total nonsense.
     
    Last edited: Aug 8, 2021
  8. Ssssssss Registered Senior Member

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    Seems to me there ought to be a more efficient way to say all that. Something like "Rindler coordinates only cover the Rindler wedge" covers about 90% of it in seven words.
     
  9. Michael 345 New year. PRESENT is 72 years oldl Valued Senior Member

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    OR

    Trust the experts - Three words cover 100%

    Please Register or Log in to view the hidden image!

     
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  10. Ssssssss Registered Senior Member

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    99%. They make mistakes sometimes.
     
  11. Michael 345 New year. PRESENT is 72 years oldl Valued Senior Member

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    For a subject to have lasted as long as it has I think any mistakes would have washed out by now

    This, to me, would be the moment to ADD some new factor requiring explanation

    Since my knowledge is zero I cannot fathom if this is occurring with the diagrams being presented

    Do not know where your 99% comes from BUT I would take it as a given 99% of Social Media posters on such complex subjects would be incorrect

    Please Register or Log in to view the hidden image!

     
  12. Ssssssss Registered Senior Member

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    Relativity is only a bit over a century old which is less than half the age Newtonian physics was when relativity came along and stuff like Bell's spaceship paradox can trip even pros if they haven't seen it before although usually they have the sense and mathematical chops to analyse it properly if given some time.

    But this thread is just saying that MCIF don't work for accelerating observers which isn't quite right. They work fine if \(d<c^2/A\) because the simultaneity planes don't cross in the region of interest.
    I've no idea what the real error rate is I just picked a number less than 100%.
     
  13. Mike_Fontenot Registered Senior Member

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    Some posters above apparently ACCEPT the CMIF result that an observer (he) who suddenly changes his velocity in a direction TOWARD a distant person (she) will conclude that she suddenly gets OLDER, but apparently DENY the CMIF result that an observer (he) who suddenly changes his velocity in a direction TOWARD a distant person (she) will conclude that she suddenly gets YOUNGER.

    But there is argument that shows that if sudden positive ageing is possible, the sudden negative ageing MUST also be possible.

    The argument goes like this: suppose the traveler, when he is distant from her, suddenly changes his velocity from v to -v. Then the CMIF method says that he must conclude that she suddenly got OLDER, say by Y years, during his velocity change. But what if he then IMMEDIATELY changes his velocity from -v to +v? The two sudden velocity changes, occurring back-to-back, are equivalent to NO velocity changes at all. The only way to end up with NO change in her age at all is if her sudden ageing by Y years is immediately followed by her sudden negative ageing by -Y years.
     
  14. Ssssssss Registered Senior Member

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    Do you mean me?
    Wrong. A coordinate system constructed from slices of momentarily comoving inertial frames can't cover the region where negative aging is supposed to take place because you would have to extend simultaneity planes to or past where they cross and then you don't have a diffeomorphism between the coordinate space and spacetime. If you're allowing instantaneous acceleration the sudden positive aging is just a coordinate system failure too. It's just like getting two maps that cover partially overlapping regions of a country and pasting them side by side and saying that because there are two copies of a thing on the map there must be two of it in reality and because there are some things not covered by the map they don't exist in reality. Maps constructed this way are bad maps and you'd be a fool to be using them.

    No one has ever observed negative aging and relativity doesn't allow it but if you abuse the MCIF method of generating coordinates by extending them through a coordinate singularity then you can generate a map of spacetime that includes negative aging but that's because you are doing maps wrong. The right thing to do is acknowledge that there are regions of spacetime that cannot be covered by these "chained" MCIFs and discontinuities are to be expected around where the gaps are. If the accelerating observer has finite proper acceleration and it never goes above \(\alpha_{\mathrm{max}}\) then the MCIF method is guaranteed to work for objects strictly less than \(c^2/\alpha_{\mathrm{max}}\) away from the accelerating observer. Beyond that you get weird effects the same way you would if you tried to push a Mercator projection beyond the poles.
     
    Last edited: Aug 8, 2021
  15. Mike_Fontenot Registered Senior Member

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    CMIF simultaneity says the accelerating observer (he) MUST adopt the conclusion (about the current age of the distant person) of the perpetually-inertial observer (PIO) who is co-located and stationary with respect to him at that instant in the his life. I.e., if that PIO concludes that the distant person is currently T years old "right then", then the accelerating observer must adopt that conclusion.

    But my question for you, Neddy, is this: Do YOU subscribe to CMIF simultaneity? I always thought you did, but I think lately, at least, you've been in the "no negative ageing" camp ... i.e., I think you hold that the accelerating observer will never conclude that the distant person is abruptly getting YOUNGER. But that is exactly what CMIF simultaneity says can happen. If you disagree with that last statement, let me know, and we can discuss some Minkowski diagrams.
     
  16. phyti Registered Senior Member

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    Mike;

    Save yourself some time.
    A clock accumulates time, and the faster it moves in space free of significant gravity, the slower its rate of accumulation. It never runs backwards.
    In a gravitational field, a clock made on the earth surface will run faster as it moves away from the surface, but the increase in rate is a result of lesser gravitational effect.
    Therefore there is no basis for negative aging, and no need of a proof.
     
  17. DaveC426913 Valued Senior Member

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    Indeed. Same concise answer for this thread, as well as the duplicate thread in Alt Theories.
     
  18. Mike_Fontenot Registered Senior Member

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  19. Mike_Fontenot Registered Senior Member

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  20. DaveC426913 Valued Senior Member

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    And - as in the duplicate thread in the Alt Theories forum - this video is still unavailable, so we'll have to assume you're interpreting it wrong - again. For the third time, in fact.

    (Did you even bother to check the link this time? Or did you just mindlessly copy and paste it from your duplicate thread in the Alt Theories forum?)
     
  21. Ssssssss Registered Senior Member

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    The video is also on Youtube Skip everything up to the thanking of the funders then look at the transcript on the PBS site. The video is actually illustrating the Andromeda paradox where at the same time as an event means different times in a distant galaxy even for frames with modest speeds. But then Greene talks about the alien in the video accelerating and so what's pictured is wrong because it shows simultaneity planes that have crossed which means they are using MCIFs outside the region where they are valid. So their alien assigns multiple coordinates to single events and gets in a muddle which does include the earthman getting younger and then older but not because that's actually happening but because the alien is using a bad map of spacetime. It works fine close to the alien but it needs a better method such as radar coordinates or just picking an inertial frame and sticking with it for such long range work.
     
    Last edited: Aug 9, 2021
  22. Q-reeus Banned Valued Senior Member

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    The dangers of relying on chart-based reasoning all covered before:
    http://www.sciforums.com/posts/3541905/
    http://www.sciforums.com/posts/3549538/
    http://www.sciforums.com/posts/3587046/
    http://www.sciforums.com/posts/3587051/

    Brian Greene himself is not above making gaffes one of which strangely seems to have never been picked up on and corrected apart from yours truly here:
    http://www.sciforums.com/threads/traveling-toward-a-light-source.160434/#post-3496506
    http://www.sciforums.com/threads/traveling-toward-a-light-source.160434/#post-3496738

    [PS - My last link within a link to above PBS channel vid now out of date. The YouTube one used by previous poster is to the same vid but the equivalent time slot there is now ~ 16:10 to 17:30 mark minutes:seconds.]
     
    Last edited: Aug 9, 2021
  23. Ssssssss Registered Senior Member

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    Understatement and a half. This stuff isn't all that complicated but the traps aren't obvious and you need attention to boring detail which isn't a thing in the big picture only approach of pop science. I guess Greene knows better but his editors don't.
     
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