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A simple and surprisingly realistic model of the origin of the universe can be developed using the Friedmann equation from general relativity, elementary quantum mechanics, and the experimental values of h, c, G and the proton mass. The…

General Relativity and Quantum Cosmology · Physics 2015-06-25 T. R. Mongan

In relativistic inhomogeneous cosmology, structure formation couples to average cosmological expansion. A conservative approach to modelling this assumes an Einstein--de Sitter model (EdS) at early times and extrapolates this forward in…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Boudewijn F. Roukema , Pierre Mourier , Thomas Buchert , Jan J. Ostrowski

Cosmological parameters can be measured by comparing peculiar velocities with those predicted from a galaxy density field. Previous work has tested the accuracy of this approach with N-body simulations, but generally on idealised mock…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-27 Amber M. Hollinger , Michael J. Hudson

We estimated the Galactic model parameters by means of a new approach based on the comparison of the observed space density functions per absolute magnitude interval with a unique density law for each population individually, and via the…

Astrophysics · Physics 2009-11-10 S. Karaali , S. Bilir , E. Hamzaoglu

In order to test the expansion of the universe and its geometry, we carry out an Alcock & Paczynski cosmological test, that is, an evaluation of the ratio of observed angular size to radial/redshift size. The main advantage of this test is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Martin Lopez-Corredoira

Starting from the revelation of the nature of inertial forces, this article discusses the subdivision of the basic physical concept of space-time and raises questions about the metric of standard cosmology. A new form of particle dynamics…

High Energy Physics - Theory · Physics 2024-06-25 ChiYi Chen

The formula for the dark energy, derived by Padmanabhan in a recent Letter to Editor (Class.Quantum Grav. September 2005, the formula given in its Abstract), was actually derived 4 years earlier ourselves in astro-ph/0105245; Mod.Phys.Lett.…

Astrophysics · Physics 2007-05-23 V. G. Gurzadyan , S. -S. Xue

In this study, by revisiting the quantum interpretation of the cosmological constant, we introduce its formal representation within standard General Relativity. Examining its behavior in a Friedmann-Robertson-Walker spacetime reveals a…

General Relativity and Quantum Cosmology · Physics 2026-02-26 H. R. Fazlollahi

Based on magnitudes and Petrosian radii from the Sloan Digital Sky Survey (SDSS, data release 7) at low redhift (z <0.2), we developed a test of galaxy-size evolution. For this first quantitative size analysis using SDSS data, several…

General Physics · Physics 2015-03-17 Alexander Unzicker , Karl Fabian

The extent to which the projected distribution of stars in a cluster is due to a large-scale radial gradient, and the extent to which it is due to fractal sub-structure, can be quantified -- statistically -- using the measure ${\cal Q} =…

Solar and Stellar Astrophysics · Physics 2015-05-20 O. Lomax , A. P. Whitworth , A. Cartwright

A model is presented for the origin of the large scale structure of the universe and their Mass-Radius scaling law; a fractal power law, $M \propto R^D$, with dimension $D=2$, most significantly. The physics is conventional, orthodox, but…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 Norman E. Frankel

Friedmans cosmological equations for the scale factor are analyzed for the Universe containing dark energy. The parameter of the equation of state of the dark energy is treated as an arbitrary constant whose value lies within the interval…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-13 M. V. Sazhin , O. S. Sazhina , U. Chadayammuri

This paper is based on two insights: (1) that general relativity alone does not specify how much of the matter density contributes to the source term in Friedmann's equation, and how much contributes as the source of the gravitational…

General Relativity and Quantum Cosmology · Physics 2024-04-23 Richard J. Cook

Standard cosmology is constructed upon the (generally implicit) assumption of the ``large scale'' homogeneity of our Universe. Now, structures are observed at scales which become larger and larger as the observational distances increase.…

Astrophysics · Physics 2007-05-23 Marie-Noelle Celerier

We propose that the observed value of the cosmological constant may be explained by a fundamental uncertainty in the spacetime metric, which arises when combining the principle that mass and energy curve spacetime with the quantum…

General Relativity and Quantum Cosmology · Physics 2025-05-20 Ahmed Farag Ali , Nader Inan

The backbone of standard cosmology is the Friedmann-Robertson-Walker solution to Einstein's equations of general relativity (GR). In recent years, observations have largely confirmed many of the properties of this model, which is based on a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Fulvio Melia , Andrew Shevchuk

In a recently proposed theory, the cosmological constant (CC) does not curve spacetime in our universe, but instead gets absorbed into another universe endowed with its own dynamical metric, nonlocally coupled to ours. Thus, one achieves a…

High Energy Physics - Theory · Physics 2016-12-07 Gregory Gabadadze , Siqing Yu

A long standing question in cosmology is whether gravitational lensing changes the distance-redshift relation $D(z)$ or the mean flux density of sources. Interest in this has been rekindled by recent studies in non-linear relativistic…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-16 Nick Kaiser , John A. Peacock

The recent measurements of the Hubble constant based on the standard $\Lambda$CDM cosmology reveal an underlying disagreement between the early-Universe estimates and the late-time measurements. Moreover, as these measurements improve, the…

General Physics · Physics 2020-11-25 Ram Gopal Vishwakarma

We propose and implement a novel test to assess deviations from well-established concordance $\Lambda$CDM cosmology while inferring dark energy properties. In contrast to the commonly implemented parametric forms of the dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-27 Upala Mukhopadhyay , Sandeep Haridasu , Anjan A Sen , Suhail Dhawan
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