Why the speed of light is always constant to every observer?

1 Answer

Velocity of light is a universal constant. It does not change even is observer moves or source moves.

Explanation:

When he combined the principle of relativity with the constant speed of light, it became clear to Einstein that the speed of light was also independent of the speed of the observer (as well as of the speed of the source of the light), and that everyone in the universe, no matter how fast they were moving, would always ...
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