• Time Dilation on the International Space Station

    From Keith Stein@21:1/5 to Keith Stein on Mon May 14 02:58:12 2018
    On 14/05/2018 02:53, Keith Stein wrote:



    https://en.wikipedia.org/wiki/File:Daily_satellite_time_dilation.png

    Sorry i messed up the link - That should work now.


    Why don't you measure time dilation on the ISS ?
    Physicists are claiming that clocks on the ISS would lose 24.6 us/day, whereas clocks on the GPS are claimed to gain 37 us/day. Since the
    clocks are in free fall in both cases this seems highly unlikely to me.

    However the physicists claim that,due to the higher velocity and lower altitude of the ISS, the direction of the time dilation would reverse.
    If it is really true this would indeed be a spectacular demonstration
    of the correctness of Einstein's Special and General Relativity, but
    I don't believe it myself.

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  • From Keith Stein@21:1/5 to All on Mon May 14 02:53:47 2018
    https://en.wikipedia.org/wiki/File:Daily_satellite_time_dilation.pngT

    Why don't you measure time dilation on the ISS ?
    Physicists are claiming that clocks on the ISS would lose 24.6 us/day,
    whereas clocks on the GPS are claimed to gain 37 us/day. Since the
    clocks are in free fall in both cases this seems highly unlikely to me.

    However the physicists claim that,due to the higher velocity and lower
    altitude of the ISS, the direction of the time dilation would reverse.
    If it is really true this would indeed be a spectacular demonstration
    of the correctness of Einstein's Special and General Relativity, but
    I don't believe it myself.

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeff Findley@21:1/5 to All on Mon May 14 06:16:16 2018
    In article <I_5KC.76404$7b4.23684@fx12.am4>, keithstein111@gmail.com
    says...

    https://en.wikipedia.org/wiki/File:Daily_satellite_time_dilation.pngT

    Why don't you measure time dilation on the ISS ?
    Physicists are claiming that clocks on the ISS would lose 24.6 us/day, whereas clocks on the GPS are claimed to gain 37 us/day. Since the
    clocks are in free fall in both cases this seems highly unlikely to me.

    Time dilation happens due to the difference in velocity between two
    points. It absolutely happens. GPS takes that into account due to the
    precise timings required (i.e. since it's used on earth, the time
    reference is adjusted such that receivers on the earth get the correct
    time).

    I'm not sure how ISS sets its clocks, but the computers are all
    networked together, so no doubt they're using the same time reference.
    In practice this isn't really a big deal since the difference in
    velocity isn't that great.

    However the physicists claim that,due to the higher velocity and lower altitude of the ISS, the direction of the time dilation would reverse.
    If it is really true this would indeed be a spectacular demonstration
    of the correctness of Einstein's Special and General Relativity, but
    I don't believe it myself.

    It's complex stuff. You have to take into account both general
    relativity and special relativity.

    https://en.wikipedia.org/wiki/Time_dilation

    Jeff
    --
    All opinions posted by me on Usenet News are mine, and mine alone.
    These posts do not reflect the opinions of my family, friends,
    employer, or any organization that I am a member of.

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  • From Keith Stein@21:1/5 to Jeff Findley on Mon May 14 18:45:07 2018
    On 14/05/2018 11:16, Jeff Findley wrote:
    In article <I_5KC.76404$7b4.23684@fx12.am4>, keithstein111@gmail.com
    says...

    https://en.wikipedia.org/wiki/File:Daily_satellite_time_dilation.pngT

    Why don't you measure time dilation on the ISS ?
    Physicists are claiming that clocks on the ISS would lose 24.6 us/day,
    whereas clocks on the GPS are claimed to gain 37 us/day. Since the
    clocks are in free fall in both cases this seems highly unlikely to me.

    Time dilation happens due to the difference in velocity between two
    points. It absolutely happens. GPS takes that into account due to the precise timings required (i.e. since it's used on earth, the time
    reference is adjusted such that receivers on the earth get the correct
    time).

    I'm not sure how ISS sets its clocks, but the computers are all
    networked together, so no doubt they're using the same time reference.
    In practice this isn't really a big deal since the difference in
    velocity isn't that great.

    However the physicists claim that,due to the higher velocity and lower
    altitude of the ISS, the direction of the time dilation would reverse.
    If it is really true this would indeed be a spectacular demonstration
    of the correctness of Einstein's Special and General Relativity, but
    I don't believe it myself.

    It's complex stuff. You have to take into account both general
    relativity and special relativity.

    https://en.wikipedia.org/wiki/Time_dilation

    Thank you Jeff. The link i gave at the beginning of this post comes
    from that same Wikipedia article. The graph i linked to shows clearly
    that they are claiming that clocks on the GPS GAIN 37 us/day, while
    clocks on the ISS would LOSE 24.6 us/day. I can tell you are convinced,
    even without any test on the ISS, but it seems highly improbable to me.

    A big advantage of doing the test on the ISS would be that the clocks
    could be compared while alongside each other, which would be far more
    certain and accurate than comparing clocks which are 20,000 km apart,
    and moving rapidly relative to each other, as is the case with GPS.

    Simple way to do the test on the ISS:
    1. Synchronize two clocks.
    2. Take one to the ISS.
    3. Next flight up take up the other.
    4. Compare the two clocks on the ISS.

    keith stein



    Jeff


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  • From Jeff Findley@21:1/5 to All on Tue May 15 07:21:54 2018
    In article <zWjKC.248171$Cd3.142083@fx33.am4>, keithstein111@gmail.com
    says...

    On 14/05/2018 11:16, Jeff Findley wrote:
    In article <I_5KC.76404$7b4.23684@fx12.am4>, keithstein111@gmail.com says...

    https://en.wikipedia.org/wiki/File:Daily_satellite_time_dilation.pngT

    Why don't you measure time dilation on the ISS ?
    Physicists are claiming that clocks on the ISS would lose 24.6 us/day,
    whereas clocks on the GPS are claimed to gain 37 us/day. Since the
    clocks are in free fall in both cases this seems highly unlikely to me.

    Time dilation happens due to the difference in velocity between two
    points. It absolutely happens. GPS takes that into account due to the precise timings required (i.e. since it's used on earth, the time
    reference is adjusted such that receivers on the earth get the correct time).

    I'm not sure how ISS sets its clocks, but the computers are all
    networked together, so no doubt they're using the same time reference.
    In practice this isn't really a big deal since the difference in
    velocity isn't that great.

    However the physicists claim that,due to the higher velocity and lower
    altitude of the ISS, the direction of the time dilation would reverse.
    If it is really true this would indeed be a spectacular demonstration
    of the correctness of Einstein's Special and General Relativity, but
    I don't believe it myself.

    It's complex stuff. You have to take into account both general
    relativity and special relativity.

    https://en.wikipedia.org/wiki/Time_dilation

    Thank you Jeff. The link i gave at the beginning of this post comes
    from that same Wikipedia article. The graph i linked to shows clearly
    that they are claiming that clocks on the GPS GAIN 37 us/day, while
    clocks on the ISS would LOSE 24.6 us/day. I can tell you are convinced,
    even without any test on the ISS, but it seems highly improbable to me.

    You mean something like this:

    NASA - Atomic Clock Ensemble in Space https://www.nasa.gov/mission_pages/station/research/experiments/2076.htm
    l

    Atomic Clock Ensemble in Space (ACES) data analysis https://arxiv.org/abs/1709.06491

    So the very thing you propose is planned. It doesn't look like it's
    flown to ISS yet though.

    At any rate, relativity has been proven many times before.

    https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment

    A big advantage of doing the test on the ISS would be that the clocks
    could be compared while alongside each other, which would be far more
    certain and accurate than comparing clocks which are 20,000 km apart,
    and moving rapidly relative to each other, as is the case with GPS.

    Simple way to do the test on the ISS:
    1. Synchronize two clocks.
    2. Take one to the ISS.
    3. Next flight up take up the other.
    4. Compare the two clocks on the ISS.

    Much simpler tests have already proven relativity. The equations hold
    true. There is no need to think the concept is improbable.

    Jeff
    --
    All opinions posted by me on Usenet News are mine, and mine alone.
    These posts do not reflect the opinions of my family, friends,
    employer, or any organization that I am a member of.

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