Inhomogeneous cosmology and backreaction: Current status and future
  prospects
  Astronomical observations reveal hierarchical structures in the Universe,
from galaxies, groups of galaxies, clusters and superclusters, to filaments and
voids. On the largest scales it seems that some kind of statistical homogeneity
can be observed. As a result, modern cosmological models are based on spatially
homogeneous and isotropic solutions of the Einstein equations, and the
evolution of the universe is approximated by the Friedmann equations. In
parallel to standard homogeneous cosmology, the field of inhomogeneous
cosmology and backreaction is being developed. This field investigates whether
small scale inhomogeneities via non-linear effects can backreact and alter the
properties of the Universe on its largest scales, leading to a non-Friedmannian
evolution. This paper presents the current status of inhomogeneous cosmology
and backreaction. It also discusses future prospects of the field of
inhomogeneous cosmology, which is based on a survey of 50 academics working in
the field of inhomogeneous cosmology.
