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The detection of a time variation of the angle between two distant sources would reveal an anisotropic expansion of the Universe. We study this effect of cosmic parallax within the ellipsoidal universe model, namely a particular homogeneous anisotropic cosmological model of Bianchi type I, whose attractive feature is the potentiality to account for the observed lack of power of the large-scale cosmic microwave background anisotropy. The preferred direction in the sky, singled out by the axis of symmetry inherent to planar symmetry of ellipsoidal universe, could in principle be constrained by future cosmic parallax data. However, that will be a real possibility if and when the experimental accuracy will be enhanced at least by two orders of magnitude.
Cosmic parallax is the change of angular separation between pair of sources at cosmological distances induced by an anisotropic expansion. An accurate astrometric experiment like Gaia could observe or put constraints on cosmic parallax. Examples of a
Refined astrometry measurements allow us to detect large-scale deviations from isotropy through real-time observations of changes in the angular separation between sources at cosmic distances. This cosmic parallax effect is a powerful consistency tes
Despite the great observational success of the standard cosmological model some discrepancies in the inferred parameter constraints have manifested among a number of cosmological data sets. These include a tension between the expansion rate of our Co
[Abridged] In a Universe with a detectable nontrivial spatial topology the last scattering surface contains pairs of matching circles with the same distribution of temperature fluctuations - the so-called circles-in-the-sky. Searches for nearly antip
In this paper we attempt to answer to the question: can cosmic acceleration of the Universe have a fractal solution? We give an exact solution of a Lema^itre-Tolman-Bondi (LTB) Universe based on the assumption that such a smooth metric is able to des