• hglman@lemmy.ml
      link
      fedilink
      English
      arrow-up
      26
      ·
      6 months ago

      UTC doesn’t become wrong, you can either just accept a different pace of the clock, i.e. earth ppl will be ever so late to a meeting or it’s just a different kind of timezone conversion. Better would be to have a single time based on the reference frame of the center of the galaxy and everyone keep there time relative to that.

      • Vilian@lemmy.ca
        link
        fedilink
        arrow-up
        10
        arrow-down
        2
        ·
        6 months ago

        just use a time based on light?, like meter is based on the speed fo light in the vaccum, or use atomic based times?, like how long take for the hydrogen atom todo something bla bla bla

        • far_university1990@feddit.de
          link
          fedilink
          arrow-up
          12
          arrow-down
          3
          ·
          6 months ago

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

          The second […] is defined by taking the fixed numerical value of the caesium frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.

          Do not matter for relativity though, always same change.

          • Resonosity@lemmy.world
            link
            fedilink
            arrow-up
            2
            ·
            6 months ago

            So are you saying that a caesium-133 atom observed on both the Earth and the Moon to oscillate 9,192,631,770 times will not represent the same absolute span of time?

            So, one observer will see those oscillations happen faster than the other?

            Does this have to do with the specific gravity fields of both observers, in that those fields affect how the atom oscillates?

            Or is there something else I’m missing?

            If special relativity is the answer, all good. I’m an electrical engineer trained in classic physics, so I’ll rest knowing that I’d probably need to study that to understand the time differences.

            • NielsBohron@lemmy.world
              link
              fedilink
              English
              arrow-up
              5
              ·
              edit-2
              6 months ago

              So, one observer will see those oscillations happen faster than the other?

              Not quite. In each observer’s frame of reference, time appears to pass the same; it’s only when you try to reconcile the between two objects that are not at rest with respect to each other does relativity show up.

              Basically, when you bring someone back to Earth, the observers will find that their watches don’t match up even though both observers experience time passing the same way as normal (because the oberserver is by definition at rest with respect to their own frame of reference).

              TL; DR: Relativity is a pain in the ass and makes no sense in everyday terms.

              edit: disclaimer - I am not a physicist and have not taken physics classes in a decade plus, but I do teach science at a college. I’m going mostly on half-remembered lectures and some random one-off discussions I’ve had with my buddy in the physics department over the past few years.

    • barsoap@lemm.ee
      link
      fedilink
      arrow-up
      1
      arrow-down
      3
      ·
      edit-2
      6 months ago

      No the second is still 9192631770 hyperfine transitions of Cs-133 on the moon and that’s the same length of time at least unless you want to severely annoy physicists by implying that the laws of nature aren’t constant throughout the universe. It’s just that from our perspective it looks like time is flowing differently there.

      • SmoothLiquidation@lemmy.world
        link
        fedilink
        English
        arrow-up
        5
        arrow-down
        1
        ·
        6 months ago

        You are correct that if you are on thee moon and have a cs-133 atom with you is second will take that many transitions. And if you do the same thing on Earth, a second will take the same number of transitions.

        But things get weird when you are on earth and observe a cs-133 atom that is on the moon. Because you are in different reference frames, you are traveling at different speeds and are in different gravity wells time is moving at different rates. This means that a cs atom locally will transition a different number of times in a second from your point of view on Earth vs one you are observing on the moon.

        And it would all be reversed if you were on the Moon observing a clock back on the Earth.

        They already have to account for this with GPS satellites. They all have atomic clocks on them but they don’t run at the same speed as clocks that are on the ground. The satellites are moving at a great speed and are further from the center of the earth than us, so the software that calculates the distance from your phone to the satellite have to use Einstein’s equations to account for the change in the rate of time.

        Relativity is weird.