Comments on 'On the speed of gravity and the Jupiter/quasar measurement' by S. Samuel

摘要

A recent review article by S. Samuel "On the Speed of Gravity and the Jupiter/Quasar Measurement" published as Int. J. Mod. Phys. D 13, 1753 (2004), provides the reader with a misleading "theory" of the relativistic time delay in the general theory of relativity. Furthermore, it misquotes original publications by Kopeikin and Fornalont and Kopeikin related to the measurement of the speed of gravity by VLBI. We summarize the general relativistic principles of the Lorentz-invariant theory of the propagation of light in a time-dependent gravitational field, derive a Lorentz-invariant expression for the relativistic time delay, and finally explain why Samuel's "theory" is conceptually incorrect and confuses the speed of gravity with the speed of light.