Ehrenfest paradox and the meaning of its nonresolution.

In the special theory of relativity, proper lengths of rods and rulers remain unaltered. However, noncomoving rods and rulers (appear to) contract along the line of movement. This contraction is asserted to be as real as any conceivable physical measurement that is made by the reference frame with respect to which the rods and rulers are moving. It is well recognized that the contraction is a result of a mismatch in synchronization of spatially separated clocks. The Ehrenfest paradox highlights the anomalies created by (apparent) length contraction that is real for the noncomoving frame yet nonexistent for the comoving frame. Ehrenfest, a reputed theoretical physicist of his times, himself did not offer a solution to the paradox, indicating that the paradox is a critique of the special relativity theory. There is no consensus on the resolution of the paradox except evasive ones such as the clocks on the circumference cannot be synchronized by any acceptable procedure or the impossibility of maintaining rigidity during the transition. The original paradox proposed by Ehrenfest envisaged contraction of the circumference. The counterview proposed by Einstein that the rulers on the circumference contracted, leading to a measurement of a larger circumference, only exasperates the paradox. Thus, the paradox remains unresolved, causing doubts about the maintainability of the theory of special relativity. The difficulties that preclude the possibility of an acceptable synchronization in the rotating frame lead to an impossibility of observing any reality, absolute or otherwise. This is because without synchronization of spatially separated clocks, it is not possible to measure the length of a moving rod. Since there must be a reality, absolute or otherwise, we suggest that there must be a synchronization that corresponds to reality. [ABSTRACT FROM AUTHOR]