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In a recent post I said

"The speed of light is the same for all observers".

I meant unequivocally. With no exceptions. Always the same. No tricks or gimmicks.

But I was quickly corrected in triplicate!

'To be exact: The speed of light is the same for all inertial observers. There is a significant difference.'

If the difference is significant, then I need to understand it. Does this mean the speed of light can change for an observer?

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# Subtle Distinction

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