Inhomogeneity-Induced Cosmic Acceleration in a Dust Universe

Chuang, Chia-Hsun; Gu, Je-An; Hwang, W-Y. P.

Inhomogeneity-Induced Cosmic Acceleration in a Dust Universe

Authors

Chuang, Chia-Hsun

Gu, Je-An

Hwang, W-Y. P.

Description

It is the common consensus that the expansion of a universe always slows down if the gravity provided by the energy sources therein is attractive and accordingly one needs to invoke dark energy as a source of anti-gravity for understanding the cosmic acceleration. To examine this point we find counter-examples for a spherically symmetric dust fluid described by the Lemaitre-Tolman-Bondi solution without singularity. Thus, the validity of this naive consensus is indeed doubtful and the effects of inhomogeneities should be restudied. These counter-intuitive examples open a new perspective on the understanding of the evolution of our universe.
41 pages, 12 figures, 4 tables; final version for publication