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In the standard cosmological framework, the Hubble diagram is interpreted by assuming that the light emitted by standard candles propagates in a spatially homogeneous and isotropic spacetime. However, the light from "point sources"--such as…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-02 Pierre Fleury , Hélène Dupuy , Jean-Philippe Uzan

We discuss physical interpretation of {\Lambda}CDM cosmology from a Machian model of the universe containing nothing but visible matter (ordinary matter, radiation). The Friedmann equation can be derived from a Machian definition of energy,…

General Relativity and Quantum Cosmology · Physics 2016-06-28 Herman Telkamp

We construct high-precision models of the Universe that contain radiation, a cosmological constant, and periodically distributed inhomogeneous matter. The density contrasts in these models are allowed to be highly non-linear, and the…

General Relativity and Quantum Cosmology · Physics 2017-02-24 Viraj A. A. Sanghai , Timothy Clifton

The recently introduced relativistic Lagrangian darkon fluid model (EPJ C (2015) 75:9) is generalized to a self-gravitating, irrotational, pressure-less and stress free geodesic fluid, whose energy-momentum tensor is dust-like with…

General Physics · Physics 2016-04-18 Peter C. Stichel

The standard model of cosmology is based on the hypothesis that the Universe is spatially homogeneous and isotropic. When interpreting most observations, this cosmological principle is applied stricto sensu: the light emitted by distant…

General Relativity and Quantum Cosmology · Physics 2024-01-15 Pierre Fleury

We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…

Astrophysics · Physics 2007-05-23 Carmelita Carbone , Sabino Matarrese

In this letter, we outline an inhomogeneous model of the Big Bang cosmology. For the inhomogeneous spacetime used here, the universe originates in the infinite past as the one dominated by vacuum energy and ends in the infinite future as…

Astrophysics · Physics 2007-05-23 Sanjay M. Wagh

In this paper we introduce a LTB-Bianchi I (plane symmetric) model of Universe. We study and solve Einstein field equations. We investigate the effects of such model of Universe in particular these results are important in understanding the…

General Relativity and Quantum Cosmology · Physics 2015-01-28 G. Fanizza , L. Tedesco

We use de Vaucouleurs' power-law density-distance relation, to study a hierarchical perturbation of the Friedmann universe. We solve the Einstein equation and obtain the density contrast and the amplification factor for the perturbation. It…

Astrophysics · Physics 2008-02-03 E. Abdalla , Roya Mohayaee

In the late 1990s, observations of type Ia supernovae led to the astounding discovery that the universe is expanding at an accelerating rate. The explanation of this anomalous acceleration has been one of the great problems in physics since…

General Physics · Physics 2015-11-09 Wun-Yi Shu

A classical dynamical system in a four-dimensional Euclidean space with universal time is considered. The space is hypothesized to be originally occupied by a uniform substance, pictured as a liquid, which at some time became supercooled.…

High Energy Physics - Theory · Physics 2013-06-19 Michael Grady

The fundamental laws of physics are required to be invariant under local spatial scale change. In 3-dimensional space, this leads to a variation in Planck constant \hbar and speed of light c. They vary as \hbar ~ a^(1/2) and c ~ a^(-1/2), a…

General Physics · Physics 2013-02-28 Hoang K. Nguyen

With the beginning of the XXIst century, a physical model of our Universe, usually called the Standard Cosmological Model (SCM), is reaching an important level of consolidation, based on accurate astrophysical data and also on theoretical…

Astrophysics · Physics 2007-05-23 Antonio L. Maroto , Juan Ramirez

Saulder et al [2019, A&A, 622, A83; arXiv:1811.11976] have performed a novel observational test of the local expansion of the Universe for the standard cosmology as compared to an alternative model with differential cosmic expansion. Their…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-10 David L. Wiltshire

The Cosmological Principle in it's various versions states that: (i) the Galaxy does not occupy a particular position, (ii) the Universe is homogeneous and isotropic. This statement does not agree with the recent astronomical observations…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-01 L. Zaninetti

A generalized quintessence model is presented which corresponds to a richer vacuum structure that, besides a time-dependent, slowly varying scalar field, contains a varying cosmological term. From first principles we determine a number of…

Astrophysics · Physics 2009-10-31 Pedro F. Gonzalez-Diaz

The assumption of a flat Universe that follows the cosmological principle, i.e., that the universe is statistically homogeneous and isotropic at large scales, comprises one of the core foundations of the standard cosmological model --…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-24 Mariana L. S. Dias , Antônio F. B. da Cunha , Carlos A. P. Bengaly , Rodrigo S. Gonçalves , Jonathan Morais

We consider a novel mechanism to account for the observed distance-redshift relation. This is done by presenting a toy model for the large-scale matter distribution in a static Universe. Our model mainly concerns particles with masses far…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-13 Nathan W. C. Leigh , Or Graur

The existence of a set of $10$ Intrinsic Conformal Symmetries, which acts on three-dimensional hypersurfaces (spacelike or timelike), leads to the existence of two distinct families of 5D geometries. These models represent the general…

General Relativity and Quantum Cosmology · Physics 2024-12-06 Pantelis S. Apostolopoulos , Noeleen Naidoo

We consider a test of the Copernican Principle through observations of the large-scale structures, and for this purpose we study the self-gravitating system in a relativistic huge void universe model which does not invoke the Copernican…

General Relativity and Quantum Cosmology · Physics 2016-12-14 Ryusuke Nishikawa , Ken-ichi Nakao , Chul-Moon Yoo
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