Speed of gravity and gravitomagnetism

TL;DR

This paper reinterprets a 2002 VLBI observation of Jupiter's gravitational effects, attributing the observed correction to light aberration in a refractive medium rather than measuring gravity's speed.

Contribution

It proposes that the observed time delay correction is due to light aberration in a refractive medium, challenging the interpretation of it as a measurement of gravity's speed.

Findings

The correction is caused by light aberration, not gravity's finite speed.

The effect is due to Jupiter's Schwarzschild field, not gravitomagnetic effects.

The observed correction aligns with Lorentz invariance in weak gravitational fields.

Abstract

A v_J/c correction to the Shapiro time delay seems verified by a 2002 Jovian observation by VLBI. In this Essay, this correction is interpreted as an effect of the aberration of light in an optically refractive medium which supplies an analog of Jupiter's gravity field rather than as a measurement of the speed of gravity, as it was first proposed by other authors. The variation of the index of refraction is induced by the Lorentz invariance of the weak gravitational field equations for Jupiter in a uniform translational slow motion with velocity v_J=13.5 km/s. The correction on time delay and deflection is due not to the Kerr (or Lense-Thirring) stationary gravitomagnetic field of Jupiter, but to its Schwarzschild gravitostatic field when measured from the barycenter of the solar system.