Accelerated expansion from structure formation

By S. Rasanen. 2006

198 citations recorded by the source corpus.

We discuss the physics of backreaction-driven accelerated expansion. Using the exact equations for the behaviour of averages in dust universes, we explain how large-scale smoothness does not imply that the effect of inhomogeneity and anisotropy on the expansion rate is small. We demonstrate with an analytical toy model how gravitational collapse can lead to acceleration. We find that the conjecture of the accelerated expansion being due to structure formation is in agreement with the general observational picture of structures in the universe, and more quantitative work is needed to make a detailed comparison.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/52008b9fc48c3acb7384508098fef4863685b493

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Citations in the corpus

Influence of global cosmological expansion on local dynamics and kinematics (2008, background): “As an example we mention recent serious efforts to interpret the same data that are usually taken to prove the existence of a positive cosmological constant Λ in a context with realistic inhomogeneities (Buchert, 2000; Räsänen, 2006; Wiltshire, 2007), i.”
Backreaction in Late-Time Cosmology (2011, methodology): “ce of statistical homogeneity and isotropy. Since the evolution of structures is governed by the proper time, one can argue that this hypersurface is close to the hypersurface of constant proper time [8,58,96]. However, the two hypersurfaces are not exactly the same, and in the realistic case when t”
The effect of inhomogeneous expansion on the supernova observations (2006, background): “2.1 The Lemaitre-Tolman-Bondi metric 5 2.2 Relation of the inhomogeneities to the observations of light 7”
Dark Energy from structure: a status report (2007, methodology): “niverse and within our past–lightcone. Therefore, with this assumption, averaging over non–causally connected regions delivers the same values as those already accumulated up to the homogeneity scale [161], [42]. We are now brieﬂy describing some exact solutions, and we mai nly have in mind to learn”
The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity (2012, background): “If we assume that GR holds, but take inhomogeneities into account, it can be shown that backreaction can cause a global cosmic acceler- ation, without any additional dark energy component (see e.g. Schwarz 2002; Kolb et al. 2005; Räsänen 2006; Wiltshire 2007a; Buchert 2008; Räsänen 2011).”