Special relativity experiments explained from the perspective of the rotating frame

In this paper, we present an explanation of several fundamental tests of special relativity from the perspective of the frame co-moving with a rotating observer. The solution is of great interest for real-time applications because Earth-bound laboratories are inertial only in approximation. We present the derivation of the Sagnac, Michelson–Morley, Kennedy–Thorndike and the Hammar experiments as viewed from the Earth-bound uniformly rotating frame or, as in the case of the Mossbauer rotor experiments, from the perspective of the rotating device. An entire section is dedicated to length/time measurement and to clock synchronization and another one to the Doppler effect and aberration on uniformly rotating platforms. This paper brings new information in the following areas: – new approach for clock synchronization on a rotating platform – new approach for length measurement in rotating frames – new explanation of the Doppler effect and of the Mossbauer rotor experiment – new explanation of the Kennedy–Thorndike experiment. The main thrust of this paper is to give a consistent explanation of various tests of special relativity as judged from the perspective of the rotating frame of the experimental setup. In addition, we correct certain misconceptions relative to clock synchronization and length measurement that have survived a long time in the specialty literature. A special chapter is dedicated to the derivation of the Doppler effect and of aberration in rotating frames. It is shown that such derivation is far from being trivial.

Comment on “New proof of general relativity through the correct physical interpretation of the Mössbauer rotor experiment” by C. Corda

We analyze the attempt by C. Corda to explain the results of modern Mössbauer experiments in a rotating system via the additional effect of synchronization of the clock in the origin of the rotating system with the laboratory clock, and indicate errors committed by him.

Mössbauer rotor experiment as new proof of general relativity: Rigorous computation of the additional effect of clock synchronization

We received an Honorable Mention at the Gravity Research Foundation 2018 Awards for Essays on Gravitation by showing that a correct general relativistic interpretation of the Mössbauer rotor experiment represents a new, strong and independent proof of Einstein’s general theory of relativity (GTR). Here, we correct a mistake which was present in our previous computations on this important issue by deriving a rigorous computation of the additional effect of clock synchronization. Finally, we show that some recent criticisms on our general relativistic approach to the Mössbauer rotor experiment are incorrect, by ultimately confirming our important result.

The validity of an experiment testing the influence of acceleration on time dilation using a rotating Mössbauer absorber and a Synchrotron Mössbauer Source

Three experiments are reviewed, performed (in 2014–2016) at ID18 of ESRF to measure the influence of acceleration on time dilation by measuring the relative shift between the absorption lines of two states of the same rotating absorber with accelerations anti-parallel and parallel to the incident beam. Statistically significant data for rotation frequencies up to 510 Hz in both directions of rotation were collected. For each run with high rotation, a stable statistically significant `vibration-free' relative shift between the absorption lines of the two states was measured. This may indicate the influence of acceleration on time dilation. However, the measured relative shift was also affected by the use of a slit necessary to focus the beam to the axis of rotation to a focal spot of sub-micrometre size. The introduction of the slit broke the symmetry in the absorption lines due to the nuclear lighthouse effect and affected the measured relative shift, preventing to claim conclusively the influence of acceleration on time dilation. Assuming that this loss of symmetry is of first order, the zero value of the relative shift, corrected for this loss, falls always within the experimental error limits, as predicted by Einstein's clock hypothesis. The requirements and an indispensable plan for a conclusive experiment, once the improved technology becomes available, is presented. This will be useful to future experimentalists wishing to pursue this experiment or a related rotor experiment involving a Mössbauer absorber and a synchrotron Mössbauer source.

Einstein’s “Clock Hypothesis” and Mössbauer Experiments in a Rotating System

An extra energy shift between emitted and received radiation on a rotating disc – next to the conventionally recognised second-order Doppler shift – has been revealed in a series of recent Mössbauer experiments, where a radioactive source is fixed at the centre and an absorber is attached to the rim of the rotating disc. This disclosure gives indication to a possible violation of the “clock hypothesis” by Einstein: i.e. the independence of the rate of a clock on its acceleration. At the moment, there seem to be two plausible interpretations of this result: (i) the deviation of the geometry of the rotating disc from that predicted by the general theory of relativity (GTR), or (ii) the existence of a specific maximal acceleration in nature, when transformation between two accelerated frames differs from the corresponding transformation of the relativity theory. We take a closer look at both ways leading to the violation of the clock hypothesis; particularly, by analysing the outcomes of recent experiments in rotating systems and by suggesting a new Mössbauer rotor experiment to determine the most feasible mechanism for testing the dependence of the rate of a clock on its acceleration.

New proof of general relativity through the correct physical interpretation of the Mössbauer rotor experiment

In this paper, we give a correct interpretation of a historical experiment by Kündig on the transverse Doppler shift in a rotating system (Mössbauer rotor experiment). This experiment has been recently first reanalyzed, and then replied by an experimental research group. The results of reanalyzing the experiment have shown that a correct re-processing of Kündig’s experimental data gives an interesting deviation of a relative redshift between emission and absorption resonant lines from the standard prediction based on the relativistic dilatation of time. Subsequent new experimental results by the reply of Kündig experiment have shown a deviation from the standard prediction even higher. By using the Equivalence Principle (EP), which states the equivalence between the gravitational “force” and the pseudo-force experienced by an observer in a noninertial frame of reference (included a rotating frame of reference), here the theoretical framework of the Mössbauer rotor experiment is reanalyzed directly in the rotating frame of reference through a general relativistic treatment. It will be shown that previous analyses missed an important effect of clock synchronization. By adding this new effect, the correct general relativistic prevision is in perfect agreement with the new experimental results. Such an effect of clock synchronization has been missed in various papers in the literature, with some subsequent claim of invalidity of the relativity theory and/or some attempts to explain the experimental results through “exotic” effects. The general relativistic interpretation in this paper shows, instead that the new experimental results of the Mössbauer rotor experiment are a new, strong and independent proof of general relativity.