A Case for an Inhomogeneous Einstein-de Sitter Universe

Abstract

We present a local-to-global cosmological framework in which cosmic acceleration emerges from structure formation in an inhomogeneous Einstein-de Sitter (iEdS) universe, without dark energy. The model exhibits a quasilinear coasting evolution toward an effective Milne state driven by growing inhomogeneities. We test the iEdS model with $H_0=72.5\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ and $\hat{I}{\text{c◯}}_{\mathrm{m},0}=0.272$ using CMB, BAO, and SN Ia data. The iEdS model fits the data comparably to $\hat{I}›$CDM and resolves the $H_0$ tension, while yielding a cosmic age $t_0\simeq 13.67\mathrm{Gyr}$ consistent with globular-cluster estimates.

Supplementary notes, analysis code, and posterior corner plots available at https://zenodo.org/records/18290574