Abstract

In order to describe physical reality, we need a special (gravity-free) relativity (SR) that is founded upon general non-uniform motions as they occur in our environment, and holds for the non-inertial reference frame of our laboratory. Such a generalized form of SR can be built upon a version of relativistic kinematics valid for non-uniform motions. From the view-point of Einstein's principle of reciprocity, the qualitative analysis of coordinate transformations allows the derivation of not only the reciprocal Lorentz transformation (RLT), involving inertial motions, but also a non-reciprocal transformation (N-RLT), called Co-Lorentz transformation (Co-LT), valid for non-uniform motions. Consequently, relativistic kinematics is a double faced theory: it assumes the RLT when the motion is inertial, and the Co-LT when the motion is non-inertial. The complementarity of RLT and Co-LT implies the complementarity of the reciprocal Einstein' special relativity (RESR) and that of the non-reciprocal ESR (N - ESR) called Co-Einstein' special relativity (Co-ESR). By neglecting the gravitational effects a relativistic electrodynamics, founded on Co-ESR, is elaborated. Some properties, related to the non-reciprocity of Co-LT, including the violation of time-reversal symmetry, are discussed. Adding to the classical RLT and RESR their corresponding complementary versions Co-LT and Co-ESR, produces a complete view of the relativity of physical reality.

Motto: Extended Special Relativity is like the Moon which shows us only one of her faces: it is Einstein's SR. The hidden face is Hertz's SR.