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Particle horizon
About: Particle horizon is a research topic. Over the lifetime, 2096 publications have been published within this topic receiving 69137 citations.
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TL;DR: In this article, the authors present the results of their confrontation of one example class of SFS models with the available cosmological data from high redshift supernovae, baryon acoustic oscillations (BAO) and the cosmic microwave background (CMB).
Abstract: Current observational evidence does not yet exclude the possibility that dark energy could be in the form of phantom energy. A universe consisting of a phantom constituent will be driven toward a drastic end known as the `Big Rip' singularity where all the matter in the universe will be destroyed. Motivated by this possibility, other evolutionary scenarios have been explored by Barrow, including the phenomena which he called Sudden Future Singularities (SFS). In such a model it is possible to have a blow up of the pressure occurring at sometime in the future evolution of the universe while the energy density would remain unaffected. The particular evolution of the scale factor of the universe in this model that results in a singular behaviour of the pressure also admits acceleration in the current era. In this paper we will present the results of our confrontation of one example class of SFS models with the available cosmological data from high redshift supernovae, baryon acoustic oscillations (BAO) and the cosmic microwave background (CMB). We then discuss the viability of the model in question as an alternative to dark energy.
16 citations
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TL;DR: In this paper, the second law of thermodynamics in the frame of general relativity is reconsidered in the case of an istotropic homogeneous universe, and there appears a direct link between the cosmological state of the universe, as expressed in terms of conformal coordinates, and quantities such as energy density, pressure, and entropy associated with the description of nature.
Abstract: The formulation of the second law of thermodynamics in the frame of general relativity is reconsidered in the case of an istotropic homogeneous universe. We show that there appears then a direct link between the cosmological state of the universe, as expressed in terms of conformal coordinates, and quantities such as energy density, pressure, and entropy associated with the description of nature. In the early universe there appears a kind of phase transition due to transfer of gravitational energy to matter associated with the cosmological expansion if the universe starts with a non-Euclidian (space) state. As a result, we may envisage the possibility of a “cold big-bang model,” in which the universe would start at zero temperature and entropy. The temperature goes then through a maximum before entering the present area of cooling related to adiabatic expansion.
16 citations
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TL;DR: In this paper, the authors present a review of some central problems, anomalies, paradoxes of Astrophysics, Cosmology and new approaches to its decisions, proposed by the Wave Universe Concept (WU Concept).
Abstract: We present the brief review of some central problems, anomalies, paradoxes of Astrophysics, Cosmology and new approaches to its decisions, proposed by the Wave Universe Concept (WU Concept). All these, anyhow, - Hot Points of modern science of Universe, about which Standard Model have not authentic answers. The represented set of brief (justified) Novels reflects very perspective directions of search. Essential from thems - Headline (and Topics): New Phenomenon-Megaquantization: Observed Megaquantum Effects in Astronimical Systems. Internal Structure of Celestial Bodies and Sun. Where is disposes the Convective Zone? Towards to Stars: Where the Heliopause will be found? Mystery of the Fine Structure Constant (FSC). Answer of the WU Concept: Theoretical Representation of the Fine Structure Constant. FSC - As Micro and Mega Parameter of the Universe. FSC, Orbits, Heliopause. What Quasars with Record Redshifts will be discovered in Future? Observed Universe: Monotonic Homogeneity and Anisotropy or Principal Hierarchy? Is the (Large - Scale) Limit of Universe exist? All answers, proposed by the Wave Universe Concept, in contrast with speculative schemes of Standard Model, are effectively verified by experience, including, - and by justified in observations prognoses. It will be waited, that namely here it is possible the real break in the understanding of these principal problems and enigmas, which Nature, infinite Universe offers (to us).
15 citations
TL;DR: In this article, a simple cosmological model with no expansion was proposed to explain the Pioneer effect, and a derivation of the equations of motion for an accelerated Pioneer-type observer in a rotating universe was presented.
15 citations
01 Jan 1984
TL;DR: In this article, a relativistic relation between an infinitely thin shell and a void is derived for various models of the universe and the motion of a void in the closed universe is also discussed.
Abstract: Enlargement of a spherical void in the expanding universe is discussed. In a nonlinear regime of density perturbation, the low-density region or a void behaves like an explosive source and the dense thin shell is formed by this explosion of the void. Israel’s formalism for an infinitely thin shell is applied to derive a relativistic relation, which is analysed for various models of the universe. The motion of a void in the closed universe is also discussed.
15 citations