An Explanation of the "Pioneer Effect" based on Quasi-Metric Relativity

Abstract

According to the socalled "quasi-metric" framework developed elsewhere, the cosmic expansion applies directly to gravitationally bound systems. This prediction has a number of observable consequences, none of which are in conflict with observation. In this paper we compare test particle motion in the nonstatic gravitational field outside a spherically symmetric source (as predicted by a quasi-metric theory of gravity) to test particle motion in the Schwarzschild geometry. It is found that if one incorrectly uses the Schwarzschild geometry (to the relevant accuracy) to represent the nonstatic quasi-metric model, the largest errors result from the mismodelling of null paths. One consequence of this is that using electromagnetic signals to track the motion of a non-relativistic particle results in the illusion that the particle is influenced by an anomalous force of size cH (where H is the Hubble parameter) directed towards the observer. This result naturally explains the apparently anomalous force acting on the Pioneer 10/11, Galileo and Ulysses spacecraft as inferred from radiometric data.