Propagation of Light in Non-Inertial Reference Frames

Abstract

We have seen in Chap. 4 that special relativity, which describes the physics of flat spacetime, provides a clear criterion for the absoluteness of acceleration in flat spacetime – the worldline of an object moving with constant velocity is a straight line, whereas the worldline of a body subjected to the ordinary (flat-spacetime) acceleration is curved. However, there are no straight worldlines in curved spacetime, which is described by general relativity. As a straight worldline in flat spacetime represents a body moving non-resistantly (i.e., by inertia) the same requirement is used in curved spacetime to define a special class of worldlines representing bodies whose motion is non-resistant (i.e., by inertia) – such worldlines are called geodesics.