Cosmological expansion and local systems: a Lema\^{i}tre-Tolman-Bondi model

TL;DR

This paper introduces a Lemaître-Tolman-Bondi model that simulates a two-body system embedded in an expanding universe, exploring the interplay between local dynamics and cosmological expansion.

Contribution

It presents a novel Lemaître-Tolman-Bondi model that captures local systems participating in cosmic expansion while remaining strongly bound.

Findings

System mimics a two-body system in an expanding universe

System remains strongly bound yet comoving with cosmic expansion

Provides insights into local-global dynamics in cosmology

Abstract

We propose a Lema\^{i}tre-Tolman-Bondi system mimicking a two-body system to address the problem of the cosmological expansion versus local dynamics. This system is strongly bound but participates in the cosmic expansion and is exactly comoving with the cosmic substratum.