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Several key relations are derived for Cosmological General Relativity which are used in standard observational cosmology. These include the luminosity distance, angular size, surface brightness and matter density. These relations are used…

Astrophysics · Physics 2008-11-26 John G. Hartnett , Firmin J. Oliveira

Evolution of a universe with homogeneous extra dimensions is studied with the benefit of a well-chosen parameter space that provides a systematic, useful, and convenient way for analysis. In this model we find a natural evolution pattern…

Astrophysics · Physics 2009-11-10 Je-An Gu , W-Y. P. Hwang , Jr-Wei Tsai

General relativistic corrections to the expansion rate of the Universe arise when the Einstein equations are averaged over a spatial volume in a locally inhomogeneous cosmology. It has been suggested that they may contribute to the observed…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-01 Xinghai Zhao , Grant J. Mathews

One of the goals of current cosmological studies is the determination of the expansion and acceleration rates of the universe as functions of redshift, and the determination of the properties of the dark energy that can explain these…

Astrophysics · Physics 2009-11-10 Ruth A. Daly , S. G. Djorgovski

Conditions for accelerated expansion of Friedmann-Robertson-Walker space-time are analyzed. Connection of this scenario with present-day observations are reviewed. It is explained how a scalar field could be responsible for cosmic…

Astrophysics · Physics 2017-08-23 C. A. Terrero-Escalante

We discuss the effect of super-Hubble cosmological fluctuations on the locally measured Hubble expansion rate. We consider a large bare cosmological constant in the early universe in the presence of scalar field matter (the dominant matter…

High Energy Physics - Theory · Physics 2018-11-28 Robert Brandenberger , Leila L. Graef , Giovanni Marozzi , Gian Paolo Vacca

The discovery that the expansion of the universe is accelerating in time is a major discovery which still awaits adequate explanation. It is generally agreed that this implies a cosmic repulsion as a result of the existence of a…

General Physics · Physics 2008-11-26 R. F. O'Connell

The redshift of galaxies is in general explained by the expansion of space. The flat space time theory of gravitation suggests an additional interpretation. In this theory gravitation is explained analogously to Maxwell's theory on a flat…

General Physics · Physics 2007-05-31 Walter Petry

The dependence of luminosity distance on observed resdhift and the cosmological parameters H and q is derived for a contracting Friedmann universe with no cosmological constant. The result is consistent with recent supernovae observations.

Astrophysics · Physics 2007-05-23 W. Q. Sumner , E. E. Vityaev

The Universe is filled with relic neutrinos, remnants from the Leptonic Era. Since the formation of galaxies started, gravitation has modified the Fermi-Dirac momentum distribution of these otherwise decoupled particles. Decelerated…

Astrophysics · Physics 2007-05-23 Richard Wigmans

The effect of the expanding universe on planetary motion is considered to first order in the Hubble constant H. Orbital elements are shown to be unaffected, but there is a small change in the connection between planetary proper time and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. Lewis Licht

The structure formation in the local Universe is considered within the weak-field modification of General Relativity involving the cosmological constant. This approach enables to describe the dynamics of groups and clusters of galaxies, to…

General Relativity and Quantum Cosmology · Physics 2025-02-06 V. G. Gurzadyan

We use standard general relativity to illustrate and clarify several common misconceptions about the expansion of the Universe. To show the abundance of these misconceptions we cite numerous misleading, or easily misinterpreted, statements…

Astrophysics · Physics 2009-11-10 Tamara M. Davis , Charles H. Lineweaver

The discovery that the cosmic expansion is accelerating has been followed by an intense theoretical and experimental response in physics and astronomy. The discovery implies that our most basic notions about how gravity work are violated on…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-15 Robert R. Caldwell , Marc Kamionkowski

Possibly the most peculiar expectation of the standard fine-tuned cosmological paradigm is that cosmic acceleration is to only be a very recent (z<1) phenomenon, with the universe being required to be decelerating at all higher redshifts.…

Astrophysics · Physics 2016-08-30 Philip D. Mannheim

We establish purely geometric or metric-based criteria for the validity of the separate universe ansatz, under which the evolution of small-scale observables in a long-wavelength perturbation is indistinguishable from a separate…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-01 Wayne Hu , Austin Joyce

The gravitational action of the smooth energy-matter components filling in the universe can affect the orbit of a planetary system. Changes are related to the acceleration of the cosmological scale size R. In a universe with significant…

Astrophysics · Physics 2008-11-26 M. Sereno , Ph. Jetzer

The coincidence problem of late cosmic acceleration constitutes a serious riddle with regard to our understanding of the evolution of the Universe. Here we argue that this problem may someday be solved -or better understood- by expressing…

Astrophysics · Physics 2008-11-26 Sergio del Campo , Ramon Herrera , Diego Pavon

We study the most general cosmological model with real scalar field which is minimally coupled to gravity. Our calculations are based on Friedmann-Lemaitre-Robertson-Walker (FLRW) background metric. Field equations consist of three…

General Relativity and Quantum Cosmology · Physics 2023-03-22 Medine Ildes , Metin Arik

Deriving the expansion history of the Universe is a major goal of modern cosmology. To date, the most accurate measurements have been obtained with Type Ia Supernovae and Baryon Acoustic Oscillations, providing evidence for the existence of…

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