3 research outputs found
An inhomogeneous alternative to dark energy?
Recently, there have been suggestions that the apparent accelerated expansion
of the universe is not caused by repulsive gravitation due to dark energy, but
is rather a result of inhomogeneities in the distribution of matter. In this
work, we investigate the behaviour of a dust dominated inhomogeneous
Lemaitre-Tolman-Bondi universe model, and confront it with various
astrophysical observations. We find that such a model can easily explain the
observed luminosity distance-redshift relation of supernovae without the need
for dark energy, when the inhomogeneity is in the form of an underdense bubble
centered near the observer. With the additional assumption that the universe
outside the bubble is approximately described by a homogeneous Einstein-de
Sitter model, we find that the position of the first CMB peak can be made to
match the WMAP observations. Whether or not it is possible to reproduce the
entire CMB angular power spectrum in an inhomogeneous model without dark
energy, is still an open question.Comment: 8 pages (REVTeX4), 4 figures. v2: Minor changes to text plus added
some references. Accepted for publication in PR