C = 299 792 458 m/s and uncertainty

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The speed of light, c, is defined as 299,792,458 m/s with no uncertainty due to its definition based on the distance light travels in a specific time. This definition means that rather than measuring c, we are defining it, leading to its exactness. While quantum fluctuations exist, the distances involved in measuring c are large enough that these fluctuations can be disregarded. The meter is intrinsically linked to the speed of light, reinforcing that c is a constant in this context. Therefore, the concept of measuring c as variable does not apply under the current definitions.
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c is 299 792 458 m/s without uncertainty? doesn't work the Heisenberg uncertainty principle for fotons?
 
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The distances typically involved in measuring c are sufficently big that quantum fluctuations are ignored.

Also, the length of 1m is defined by the distance light travels in a certain amount of time. Because of this definition, we're effectively defining light's speed, not measuring it, so it is exact.
 
AlphaNumeric said:
Also, the length of 1m is defined by the distance light travels in a certain amount of time. Because of this definition, we're effectively defining light's speed, not measuring it, so it is exact.
we define 1m, but we must still measure in how much time light crosses 1m; we measured c but it can be less or more, right?
 

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