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In other words, the speed of light is irrelevant. It (or relativity) doesn't dictate at all a limit on the relative speeds of two objects. This much is obvious if you consider two objects moving in oppositive directions at 51% the speed of light. Certainly valid, even though combined their relative speed from each other is >c

You can extrapolate the same to the expansion of the universe, I think, but I may be simplifying too much.



> two objects moving in oppositive directions at 51% the speed of light

> combined their relative speed from each other is >c

We've got to be very precise with the language here. That's not accurate as stated, even though I know what you mean. The relative speed of one of these objects from the other one is not greater than c. You cannot directly add relativistic velocities without making adjustments for time dilation. Adding .51 + .51 to get 1.02 is not how the math works out.

If I am sitting in the middle, observing both objects, then I see the distance between them increasing at greater than the speed of light. But that concept should not be called "relative velocity" of one object with respect to the other. That's different.

No observer can witness an object receding at or above the speed of light. At that point the redshift would completely suppresses the information from arriving.


Thanks, that's exactly what I meant!




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