I Measuring the Speed of Light: How Did We Do It?

AI Thread Summary
The speed of light is defined as 299,792,458 m/s, which was established with high precision in 1975, and the meter was redefined in 1983 based on this measurement. This redefinition was necessary because measurements of the speed of light became more accurate than previous methods of measuring length. The discussion highlights the transition from using physical objects, like a metal bar, to defining units based on fundamental constants for greater precision. Critics argue that this creates circular reasoning, but proponents assert it is a logical redefinition to enhance measurement accuracy. Overall, the shift to defining the meter through the speed of light reflects a broader trend in metrology towards stability and universality in measurement standards.
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