2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204159It has been argued that the spacetime of our universe can be accurately described by a perturbed conformal Newtonian metric, and hence even large density inhomogeneities in a dust universe can not change the observables predicted by the homogeneous dust model. In this paper we study a spherically symmetric dust model and illustrate conditions under which large spatial variations in the expansion rate can invalidate the argument.22 pages, 8 figures; replaced to fit the version accepted for publication in Phys. Rev. DAstrophysicsGeneral Relativity and Quantum Cosmologytext