Tidal Dynamics in Cosmological Spacetimes

TL;DR

This paper investigates how cosmic inhomogeneities affect local tidal forces in cosmological models and concludes that their impact on the solar system, specifically Earth's orbit, is negligible.

Contribution

It provides a detailed analysis of tidal effects in inhomogeneous cosmological spacetimes and assesses their significance for solar system dynamics.

Findings

Cosmic tidal influences on Earth's orbit are negligibly small.

Spatial inhomogeneities slightly modify local tidal accelerations.

Results support the stability of solar system scales despite cosmic inhomogeneities.

Abstract

We study the relative motion of nearby free test particles in cosmological spacetimes, such as the FLRW and LTB models. In particular, the influence of spatial inhomogeneities on local tidal accelerations is investigated. The implications of our results for the dynamics of the solar system are briefly discussed. That is, on the basis of the models studied in this paper, we estimate the tidal influence of the cosmic gravitational field on the orbit of the Earth around the Sun and show that the corresponding temporal rate of variation of the astronomical unit is negligibly small.