Abstract
The circular arc swept out by the angular displacement of a clock indicator (or its equivalent representation) measuring time is shown to be a Lorentz invariant, representing “universal” time. The concepts of time dilation and transverse Doppler effect are accordingly not physically observable. The experiments on these effects when examined critically are found to be inconclusive. Length contraction, also experimentally unconfirmed, and kinematic temporal phase, both consequences of the Lorentz transformations, are as a matter of logical consistency also physically unobservable