[aetzbar (OP)]

Two identical and synchronized clocks must be selected.
To measure active time, the measurement process - the distance between the clocks - must be constant ..
To measure passive time, in the measurement process the distance between the clocks varies.
Both measurements will not produce the same result, and a tiny difference will appear.
This difference is the passive time spent in the variable distance, which is the value
0.0033 microseconds per meter.

[Bored chemist]

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