Abstract

The theoretical foundation of LIGO?s design is based on the equation of motion derived by Thorne. His formula, motivated by Einstein?s theory of measurement, shows that the gravitational wave-induced displacement of a mass with respect to an object is proportional to the distance from the object. On the other hand, based on the observed bending of light and Einstein?s equivalence principle, it is concluded that such induced displacement has nothing to do with the distance from another object. It is shown that the derivation of Thorne?s formula has invalid assumptions that make it inapplicable to LIGO. This is a good counter example for those who claimed that Einstein?s equivalence principle is not important or even irrelevant.