• Tlaloc_Temporal
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    2 hours ago

    Yes, relatively means that light appears to move at c in every inertial reference frame. That doesn’t change how we measure distance in a single reference frame.

    How can a metre bar be measured as a metre when it’s one unit and two units long? We’re measuring the bar in it’s own reference frame each time, so relatively causes no change. Either c increased, or time slowed down to match the expansion of space. Either way, light doesn’t get redshifted by expansion.

    Help me understand, how does light appear to change speed over time in the same reference frame? How do we see a change of distance affect light between galaxies, but not between atoms?

    • wholookshere@lemmy.blahaj.zone
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      46 minutes ago

      The reason the speed of light doesn change is because rthe universe bends the rules of time to make it the same. So as the universe expands, the speed of light stays the same because the definition of time changes.

      Like I said. The expansion of the universe isn’t space expanding, it’s the definition of distance that’s expanding. Yes time is being fucked with as part of the expansion. But the universe doesn’t hold distance or time as constant frames to compare to. As speed is only calculated with a frame of reference. Where distance is a little more fundamental to the universe.

      Because the scale is so so much less. Like 73 km/s/Mpc.

      So the rate of something to the scale of 10^-9m, would be somewhere in the order of 10^-25m/s. Which is much much smaller than anything with the attoms itself.

      But the distance is always the same. A meter is still a meter in all points of time. But it’s still bigger.