The purpose of the present paper is to reply to a misleading paper by M. Sachs entitled “Einstein's later view of the Twin Paradox” (TP) (Found. Phys. 15, 977 (1985)). There, by selecting some passages from Einstein's papers, he tried to convince the reader that Einstein changed his mind regarding the asymmetric aging of the twins on different motions. Also Sachs insinuates that he presented several years ago “convincing mathematical arguments” proving that the theory of relativity does not predict asymmetrical (...) aging in the TP. Here we give a definitive treatment to the clocks problem showing that Sachs' “convincing mathematical arguments” are non sequitur. Also, by properly quoting Einstein, we show that his later view of the TP coincides with the one derived from the rigorous theory of time developed in this paper. (shrink)

In this paper we formulate Einstein's gravitational theory with the Clifford bundle formalism. The formalism suggests interpreting the gravitational field in the sense of Faraday, i.e., with the field residing in Minkowski spacetime. We succeeded in discovering the condition for this interpretation to hold. For the variables that play the role of the gravitational field in our theory, the Lagrangian density turns out to be of the Yang-Mills type (with an auto-interaction plus gauge-fixing terms). We give a brief comparison of (...) our theory with other field theories of the gravitational field in the flat Minkowski spacetime. (shrink)

Two recently proposed experiments by Kolen and Torr (K-T), designed to detect possible failures of Einstein's special relativity (SR) are analyzed. Imprecisions in these papers are pointed out. Computation in Lorentz aether theory (LAT), with the K-T violation of SR, of the theoretical prediction for the proposed K-T clock experiment prove their results to be incorrect. Analytical computation of the proposed K-T rotor Doppler experiment using LAT confirms the order of magnitude of their prediction by numerical computation. For LAT in (...) the K-T form, this experiment, using a turntable, is shown to give results which could be detected with the technology of 20 years ago. Another LAT model is considered which leads to deviations of SR smaller than in the K-T model. The central point of the approach adopted in this paper is the use of Einstein's coordinates in the comoving frame, even when SR is violated, leading always to isotropic propagation of light in vacuum; the anisotropy usually obtained in LAT is only a coordinate effect. (shrink)

This high-level study discusses Newtonian principles and 19th-century views on electrodynamics and the aether. Additional topics include Einstein's electrodynamics of moving bodies, Minkowski spacetime, gravitational geometry, time and causality, and other subjects. Highlights include a rich exposition of the elements of the special and general theories of relativity.