Gravimagnetism, Causality, and Aberration of Gravity in the Gravitational Light-Ray Deflection Experiments

TL;DR

This paper demonstrates that the extrinsic gravimagnetic field caused by moving masses can be measured through light deflection and time delay experiments, linking aberration of gravity to its causal nature and proposing improved measurement techniques.

Contribution

It introduces a method to measure the extrinsic gravimagnetic field via relativistic light deflection experiments and connects aberration of gravity with its causal properties using Lorentz transformations.

Findings

The extrinsic gravimagnetic field is generated by the relativistic aberration of gravity.

The 2002 quasar deflection experiment by Jupiter measured gravity aberration with 20% accuracy.

Proposes VLBI experiments to improve measurement accuracy of gravity aberration to a few percent.

Abstract

Experimental verification of the existence of gravimagnetic fields generated by currents of matter is important for a complete understanding and formulation of gravitational physics. Although the rotational `intrinsic' gravimagnetic field has been extensively studied and is now being measured by the Gravity Probe B, the `extrinsic' gravimagnetic field generated by the translational current of matter is less well studied. The present paper uses the post-Newtonian parametrized Einstein and light geodesics equations to show that the `extrinsic' gravimagnetic field generated by the translational current of matter can be measured by observing the relativistic time delay and/or light deflection caused by the moving mass. We prove that the `extrinsic' gravimagnetic field is generated by the relativistic effect of the aberration of the gravity force caused by the Lorentz transformation of the metric tensor and the Levi-Civita connection. We show that the Lorentz transformation of the gravity field variables is equivalent to the technique of the retarded Lienard-Wiechert gravitational potentials predicting that a light particle is deflected by gravitational field of a moving body from its retarded position so that both general-relativistic phenomena -- the aberration and the retardation of gravity -- are tightly connected and observing the aberration of gravity proves that gravity has a causal nature. We explain in this framework the 2002 deflection experiment of a quasar by Jupiter where the aberration of gravity from its orbital motion was measured with accuracy 20%. We describe a theory of VLBI experiment to measure the gravitational deflection of radio waves from a quasar by the Sun, as viewed by a moving observer from the geocentric frame, to improve the measurement accuracy of the aberration of gravity to a few percent.