2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204047If general relativity (GR) describes the expansion of the Universe, the observed cosmic acceleration implies the existence of a `dark energy'. However, while the Universe is on average homogeneous on large scales, it is inhomogeneous on smaller scales. While GR governs the dynamics of the \emph{in}homogeneous Universe, the averaged \emph{homogeneous} Universe obeys modified Einstein equations. Can such modifications alone explain the acceleration? For a simple generic model with realistic initial conditions, we show the answer to be `no'. Averaging effects negligibly influence the cosmological dynamics.5 pages, 2 figures, revtex4; v3 -- Text shortened to match published version. Some typos fixed. No physics changesAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext