Volume 20: Pages 494-502, 2007

Einstein's Equivalence Principle, the Principle of Causality, and Plane‐Wave Solutions

C. Y. Lo ¹

¹Applied and Pure Research Institute, 17 Newcastle Drive, Nashua, New Hampshire 03060 U.S.A.

Currently, Einstein's equivalence principle is commonly misunderstood. Burlankov claimed that his version of the equivalence principle in terms of Newtonian space‐time would lead to the same results as those of Einstein. It is shown that Burlankov's principle is not generally valid in physics. His plane‐wave equation has no physical solutions, although it agrees with the equation claimed to have bounded solutions by Misner, Thorne, and Wheeler. In fact, all existing plane‐wave solutions are irreducibly unbounded and thus violate Einstein's requirement on weak gravity. The equation of Misner, Thorne, and Wheeler is also a simple example that linearization of a nonlinear equation may not be valid. Concurrently, it is shown that another common source of error in general relativity is inadequate understanding of the principle of causality, on which Einstein's requirement of weak gravity is based.

Keywords: 1911 assumption of equivalence, Einstein's equivalence principle, irreducibly unbounded, principle of causality, plane wave

Received: March 28, 2007; Published Online: May 26, 2009