English
Related papers

Related papers: A Dust Universe Solution to the Dark Energy Proble…

200 papers

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy…

Astrophysics · Physics 2008-11-26 P. J. E. Peebles , Bharat Ratra

Two new one-parameter tracking behavior dark energy representations $\omega=\omega_0/(1+z)$ and $\omega=\omega_0 e^{z/(1+z)}/(1+z)$ are used to probe the geometry of the Universe and the property of dark energy. The combined type Ia…

Astrophysics · Physics 2009-11-10 Yungui Gong , Yuan-Zhong Zhang

The Friedmann equation, augmented with an additional term that effectively takes on the role of dark energy, is demonstrated to be an exact solution to the recently proposed gravitational theory named "conformal Killing gravity." This…

General Relativity and Quantum Cosmology · Physics 2023-11-20 Junpei Harada

In the contemporary Cosmology, dark energy is modeled as a perfect fluid, having a very simple equation of state: pressure is proportional to dark energy density. As an alternative, I propose a more complex equation of state, with pressure…

General Physics · Physics 2009-11-04 Dragan Slavkov Hajdukovic

Recent cosmological observations suggest that nearly seventy per cent of the energy density in the universe is unclustered and has negative pressure. Several conceptual issues related to the modeling of this component (`dark energy'), which…

Astrophysics · Physics 2008-11-26 T. Padmanabhan

Nearly seventy per cent of the energy density in the universe is unclustered and exerts negative pressure. This conclusion -- now supported by numerous observations -- poses the greatest challenge for theoretical physics today. I discuss…

Astrophysics · Physics 2009-07-09 T. Padmanabhan

To describe the dark side of the Universe, we adopt a novel approach where dark energy is explained as an electrically charged majority of dark matter. Dark energy, as such, does not exist. The Friedmann equation at the present time…

General Relativity and Quantum Cosmology · Physics 2024-04-16 Paul H. Frampton

Our universe is observed to be accelerating due to the dominant dark energy with negative pressure. The dark energy equation of state (w) holds a key to understanding the ultimate fate of the universe. The cosmic voids behave like bubbles…

Astrophysics · Physics 2011-02-11 Jounghun Lee , Daeseong Park

Experimental evidence over a number of recent years has shown the density parameter of the universe omega converging to the critical value of 1, which defines a flat, Euclidean universe. No such calculations have defined a critical value…

General Physics · Physics 2013-06-20 Peter Rowlands

A solution to Einstein's field equations via the Friedman equations is shown to produce a cosmological model that is in exact agreement with the measurements made by the dark energy astronomers. All the essential physical parameters are…

General Physics · Physics 2012-06-26 James G. Gilson

It has recently been shown that the observed Hubble function for cosmological expansion can be fitted accurately back to redshift unity (7.33 Gyr ago) with only one free constant, while neglecting cosmic curvature and mass, using the…

General Physics · Physics 2021-05-26 R. K. Nesbet

Several independent cosmological data, collected within the last twenty years, revealed the accelerated expansion rate of the Universe, usually assumed to be driven by the so called dark energy, which, according to recent estimates,…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-16 Marek Demianski , Elisabeta Lusso , Maurizio Paolillo , Ester Piedipalumbo , Guido Risaliti

Observational evidence of dark energy that makes the Universe nearly flat at the present epoch is very strong. We study the link between spatial continuity and dark energy. We assume that comoving space is a compact 3-manifold of constant…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-02 Boudewijn F. Roukema , Vincent Blanloeil

We extend and apply a model-independent analysis method developed earlier by Daly & Djorgovski to new samples of supernova standard candles, radio galaxy and cluster standard rulers, and use it to constrain physical properties of the dark…

Using an approximate solution to the $N$-body problem in general relativity, and the \emph{principle of local isotropy at any point}, we construct a cosmological model, with zero curvature, for a universe composed uniquely by collision-less…

General Relativity and Quantum Cosmology · Physics 2014-09-11 Miguel Portilla

We elaborate on a model of conformal dark energy (dynamical dark energy measured by the conformal age of the universe) recently proposed in [H. Wei and R.G. Cai, arXiv:0708.0884] where the present-day dark energy density was taken to be…

High Energy Physics - Theory · Physics 2008-11-26 Ishwaree P. Neupane

I briefly review our current understanding of dark matter and dark energy. The first part of this paper focusses on issues pertaining to dark matter including observational evidence for its existence, current constraints and the `abundance…

Astrophysics · Physics 2022-07-19 Varun Sahni

We use the angular power spectrum of the Cosmic Microwave Background, measured during the North American test flight of the BOOMERANG experiment, to constrain the geometry of the universe. Within the class of Cold Dark Matter models, we…

There is now strong evidence that the main contribution to the cosmic energy density is not due to matter, but to another component with negative pressure. Its nature is still unknown: it could be the vacuum energy, manifesting itself as a…

Astrophysics · Physics 2007-05-23 Alberto Cappi

In this paper, it is shown that the cosmological model that was introduced in a sequence of three earlier papers under the title, A Dust Universe Solution to the Dark Energy Problem, can be used to resolve the problem of the great mismatch…

General Physics · Physics 2010-07-21 James G. Gilson
‹ Prev 1 2 3 10 Next ›