2005/05/31 by J. W. Moffat · 4 citations
Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Classical mechanics #Cosmic microwave background #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Dark energy #Dark fluid #Dark matter #De Sitter universe #Deceleration parameter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitation #Isotropy #Mathematical physics #Metric expansion of space #Physics #Quantum mechanics #Universe #Void (composites) #astro-ph #gr-qc
paper · pdf · doi:10.1088/1475-7516/2006/05/001
published as JCAP 0605 (2006) 001 · LaTex file, 16 pages, no figures. Typo corrections. References added and updated. Additional material and some conclusions changed. Replacement to match final published version in Journ. Cosmol. Astropart. Phys. JCAP 2006
arxiv created 2006/04/10 · openalex publication_date 2006/05/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The inhomogeneous distribution of matter in the non-linear regime of galaxies, clusters of galaxies and voids is described by an exact, spherically symmetric inhomogeneous solution of Einstein's gravitational field equations, corresponding to an under-dense void. The solution becomes the homogeneous and isotropic Einstein–de Sitter solution for a red shift z > 10–20, which describes the matter dominated CMB data with small inhomogeneities δρ/ρ ∼ 10 −5 . A spatial volume averaging of physical quantities is introduced and the averaged time evolution expansion parameter θ in the Raychaudhuri equation can give rise in the late-time universe to a volume averaged deceleration parameter that is negative for a positive matter density. This allows for a region of accelerated expansion which does not require a negative pressure dark energy or a cosmological constant. A negative deceleration parameter can be derived by this volume averaging procedure from the Lemaître–Tolman–Bondi open void solution, which describes the late-time non-linear regime associated with galaxies and under-dense voids and solves the 'coincidence' problem.