Sagnac and Michelson‐Morley interferometers time precision evaluation

The Michelson‐Morley optical interferometric experiment is historically very important and stands at the basis of the developments that contributed to the acceptance of the special theory of relativity. 1 The Sagnac experiment is much less known and considered from the theoretical point of view, even if it presently has a large field of very useful technological applications, namely in the field of compass gyroscopes. Here, we present a discussion on the temporal precision of these devices that undoubtedly shows the great advantage of the Sagnac device design.