# Critique of the Treatment of Einstein's Special Theory of Relativity in Isaacson's Biography

Consideration is given to the properties expected for inertial systems, that is, objects which are not subject to unbalanced external forces. Isaacson points out correctly that Einstein based his version of relativity theory on the motion of such inertial systems. It is overlooked, however, in both his discussion and also the original work of Einstein himself that, consistent with Newton's First Law of Motion (Law of Inertia), the rates of inertial clocks must remain constant so long as no unbalanced force is applied to them. As a consequence, it can be safely concluded that the ratio of any two such rates must also be constant. This in turn leads to a prediction about the relationship between elapsed times measured by two inertial clocks (Newtonian Simultaneity), namely they must always occur in strict proportion to one another (Δt=QΔt'). The latter result is shown to stand in direct contradiction to the predictions of the Lorentz transformation derived by Einstein in his famous 1905 paper, namely the occurrence of space-time mixing and remote non-simultaneity (RNS). It is furthermore pointed out that the frequency of sound waves is independent of the state of motion of the source because, as Einstein argued in a 1907 paper in which he derived the gravitational red shift, the number of wave crests emitted by the source per unit time is not changed thereby. This fact has a definite bearing on Einstein's postulate of relativity according to which he assumed that the speed of light in free space is independent of the state of motion of both the observer and the source. It indicates instead that the postulate must be reformulated to state that the speed of light relative to its source is always the same in free space, a version that Einstein also carefully considered, as clearly mentioned in Isaacson's narrative. Accordingly, it becomes clear that Einstein was incorrect in his claim that the classical (Galilean velocity transformation) is not applicable to light. His relativistic velocity transformation only has validity for specific cases in which the speed of light is measured under different circumstances by a single observer, such as in the famous Fresnel/Fizeau light-drag experiment in which the motion of light waves in refractive media is investigated. The failure of the Lorentz transformation necessitates a rethinking of some of its well-known predictions such as time dilation and Lorentz-FitzGerald length contraction. Experimental evidence is presented which indicates instead that the slowing down of clocks upon acceleration is accompanied by isotropic length expansion. The applicability of these theoretical developments for the Global Positioning System of navigation is discussed. Opportunities for carrying out new experiments on this basis are also outlined in the present critique.