Tests of gravity at the solar system scale

TL;DR

This paper discusses metric extensions of General Relativity that preserve its core properties while allowing scale-dependent modifications, and evaluates their consistency with solar system gravity tests, including Pioneer probe anomalies.

Contribution

It introduces a family of metric extensions of GR that incorporate scale-dependent modifications and discusses how to test these against solar system observations.

Findings

Metric extensions preserve GR's fundamental properties.

They can account for anomalies like Pioneer probes.

Proposed tests can distinguish between GR and extensions.

Abstract

As confirmed by tests performed in the solar system, General Relativity (GR) presently represents the best description of gravitation. It is however challenged by observations at very large length scales, and already at the solar system scale, tracking of the Pioneer 10/11 probes has failed to confirm their expected behavior according to GR. Metric extensions of GR, which are presented here, have the quality of preserving the fundamental properties of GR while introducing scale dependent modifications. We show that they moreover represent an appropriate family of gravitation theories to be compared with observations when analysing gravity tests. We also discuss different tests which could allow one to determine the metric extension of GR prevailing in the solar system.