Dissecting Einstein’s Lightning-Strike Example

Abstract

Einstein’s light speed postulate (LSP) is reviewed. It claims that the speed of light is independent of both the state of motion of the light source and that of the observer. An example is considered in which a light source is initially stationary in the rest frame of the observer. The light source then moves away with constant speed v relative to the observer. At the same time a light pulse is emitted in the same direction. According to the LSP, the speed of the light pulse is equal to c relative to both the stationary observer and the light source. It is shown that the LSP is unable to justify what happens after time T has elapsed, however, namely that the distance separating the light pulse from the observer is the same (cT) as it is for the light source. This is impossible since the observer and light source are no longer located at the same position in space. This procedure is referred to as “distance reframing.” It can also be used to prove that the above example is satisfactorily described by applying the Galilean velocity transformation (GVT). It leads to the conclusion that the speed of the light pulse relative to the stationary observer is c+v. i.e. greater than c, in direct contradiction to the longstanding claim of Einstein’s Special Relativity Theory (SR). One of the consequences of this development is that Einstein’s famous example of lightning strikes on a passing train is shown to be incorrectly interpreted as proving that the strikes do not occur simultaneously for a rider on the train and an observer on the station platform.