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Roadblocks to measuring one-way speed of light

  1. Mar 4, 2015 #1
    Hi All,

    Recently I mentioned about a new method to measure the one-way speed of light. Quickly I was pointed to the existing roadblocks to such experiments, from members here and veteran professors in email. I have analyzed those roadblocks and putting here my understanding of the problems. To me they seem to be only temporary roadblocks. I have categorized them to three types. I want to hear about the problems in my understanding of the problems!!!

    Experimental difficulties:
    There are three problems (synchronizing clocks, transporting clocks, or communicating with a central point; cyclic path being part of the last) that have invalidated all experiments so far and no other choice seems to exist.
    >> To me it seems to be experimental difficulty rather than theoretical impossibility. We have overcome millions of experimental difficulties and can overcome this too. Let us not limit ourselves to current limitations! [Note: I am only talking after the fact but cannot disclose the details due to patenting.]

    One-way speed is conventionally defined to be same as two-way speed (Einstein Synchronization).
    >> It is true that we cannot measure what we have defined by convention. But, I believe that this convention was borne out of experimental limitations AND no expectation to the contrary. This convention does not prevent/prohibit ever overcoming the experimental difficulties. Actual measurement can make this convention to be a fact; less conventions are always better. Even if we all believe this convention to be true, Science needs verification whenever possible.
    There is no reason to believe that the two-way speed was preferred over one-way speed. If one-way speed were available, Einstein could have very well chosen that (and we could have had a little more complicated equations if at all it were different from two-way speed, which I don't believe).

    Frame of Reference choices: (same as Non-standard synchronization in Wikipedia?)
    By using a suitable choice of Frame, we can get any value for one-way speed of light varying between C/2 and infinity.
    >> This is only an extension of Einstein synchronization where an inertial Frame is used but here extended to include moving Frames as well. If the Einstein synchronization (isotropy) is not used, we cannot know what Frame will give what speed and the range will increase. Though all are correct choices, we should choose the simplest and stay with inertial Frame as Einstein did. There is no reason to invite complications and moving Frames while dealing with two relatively stationary observers or sensors.

    1. Choose the simplest of all choices, the Inertial Frame of Reference.
    2. Conventions do not prevent from measuring in this case, whenever possible.
    3. Experimental difficulties can be overcome.

    Request: Please let us not talk about impossibilities. We have overcome too many, including throwing things out of earth! A recent one: Mildred Dresselhaus who received Presidential Medal of Freedom for 2014 mentioned that back in the 1970s "we didn't have the patience to get monolayer graphene, and we didn't think it was possible". It got Nobel prize in 2010 by using Scotch tape!

    Thanks for any useful discussions.
  2. jcsd
  3. Mar 4, 2015 #2


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    Science Advisor

    If you can measure the one way speed of light without assuming a simultaneity convention then there must be an absolute definition of simultaneity. That isn't an "experimental difficulty", that's an outright assertion that relativity is wrong on the most fundamental level.

    Relativity is extremely well tested. A gross error of that nature would be obvious in most (all?) tests of relativity. We know your method can't work because it could only work if nearly everyone from Michelson and Morley on were outright lying about their results.

    In short: you are already talking impossibilities, and in a forum where one of the moderators already told you not to...
  4. Mar 4, 2015 #3


    Staff: Mentor

    That doesn't elminate the problem. In order to compare measurements made at different spatial locations in an inertial frame, you must have first synchronized the clocks at those different locations. An "inertial frame" is not something that magically appears out of nowhere; it is something that, experimentally, must be constructed, and part of the construction must involve synchronizing clocks.

    And with that, this thread is locked.
    Last edited: Mar 4, 2015
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