• Flying Squid@lemmy.worldOP
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    4 months ago

    I’m not insisting anything. I’m saying that, based on everything we know, the direction of light has no bearing on its speed.

    Suggesting that it does just because we don’t have evidence that it doesn’t is no different, as I said, as claiming the universe was created last Thursday.

    Maybe the speed of light doubles when it goes through the exact right type of orange. You can’t prove it doesn’t.

    • InnerScientist@lemmy.world
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      4 months ago

      This is slighlty different though, we only know the two-way speed of light, not the one way speed of light.

      We only know that this trip, to and back, takes x seconds. We cannot prove that the trip to the mirror takes the same length of time as the way back.

      The special theory of relativity for example does not depend on the one way speed of light to be the same as the two way speed of light.

      Wiki

        • vithigar@lemmy.ca
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          4 months ago

          For no reason. No one is saying that it is different, only that it’s impossible to prove one way or the other. Light traveling the same speed in all directions, and light traveling at 2x c away from an observer and instantaneously on the return, and every other alternative that averages out to c for the round trip, are indistinguishable to any experiment we can conduct.

          • Flying Squid@lemmy.worldOP
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            4 months ago

            And it’s impossible to prove that just the exact right type of orange will double the speed of light.

            But there’s no reason to speculate either thing without a reason for the speculation. Your reason seems to be “I think it would be cool.”

            I don’t think you realize it, but this is a very similar argument to “you can’t prove God doesn’t exist.”

            • vithigar@lemmy.ca
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              4 months ago

              Take 30 seconds to at least glance at the article the other user posted. It’s not just myself, there are plenty of very interested physicists who also find the unprovability of the one-way speed of light interesting.

              I’m also not sure what your point about orange is supposed to be. Are you suggesting that there is a particular spectra of light that we cannot test?

              My reason for being interested isn’t just that I think it’s “cool”. I think it’s fascinating that a fundamental underpinning of physics has such a gap in its experimental verifiability.

      • Munkisquisher@lemmy.nz
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        4 months ago

        With a detector and very accurate clocks, it would be easy to say “I’m going to send a pulse at 2pm, record when you receive it” that’s measuring it in one direction

        • InnerScientist@lemmy.world
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          4 months ago

          The very accurate clock needed in this case is physically impossible as far as we know, there’s no way to measure it as far as our current understanding of physics goes.

          Though if you can figure out a way you should publish a paper about it.

          • Richard@lemmy.world
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            4 months ago

            Can you cite some literature to back up that claim? Stating that something like acceptable clock synchronisation (a well established and appreciated method in the measurements of physical effects) is impossible in and of itself is something so bold that no one can just take your word for it.

            • InnerScientist@lemmy.world
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              4 months ago

              It is impossible to synchronize the clocks in such a way that you can actually measure the speed of light with it due to time dilation unless you define beforehand how fast the speed of light is to calculate that time dilation.

              See also This or, more accessibly “Synchronization conventions”

      • Richard@lemmy.world
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        4 months ago

        Synchronise two high-precision clocks at different locations. Transmit the signal from A to a receiver at B and then send a signal back (or reflect the initial signal) from B to A. Both locations will record the synchronised time that their sensors picked up the transmission. Then, compare their clocks.