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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, a simple derivation of the relevant expressions is given, based on the wavefront method, which is applied to observations of the quasar Q 0957+561 A, B. Assuming a simple model of this system, and using the most probable values of the observed quantities, the theory leads to an estimated Hubble age of about 17*109 years, corresponding to a Hubble parameter H0 approximately=57 km s-1 Mpc-1, which is in reasonable agreement with the results of conventional methods.
Abstract: It is explained how the Hubble age of the Universe may be determined from observation of gravitational lens images. A simple derivation of the relevant expressions is given, based on the wavefront method. The theory is applied to observations of the quasar Q 0957+561 A, B. Assuming a simple model of this system, and using the most probable values of the observed quantities, the theory leads to an estimated Hubble age of about 17*109 years, corresponding to a Hubble parameter H0 approximately=57 km s-1 Mpc-1, which is in reasonable agreement with the results of conventional methods. If the Universe has a density close to the critical mass density, this implies that the age of the Universe is about 11*109 years.
1 citations
TL;DR: In this article, a transition to a nondiagonal line element is proposed for the static Robertson-Walker universe model and the possibility of constructing scenarios without an initial singularity and "exotic" matter is discussed.
Abstract: Within GR, the problems of the Robertson-Walker universe are discussed. The approach based on transition to a nondiagonal line element is suggested. Within the considered approach, the static universe model is investigated. The possibility of constructing scenarios without an initial singularity and “exotic” matter is discussed. Accordance of the given model to the properties of the observable universe is discussed.
1 citations
TL;DR: In this article, an eternal expanding universe toy model driven by quintessence is presented, in which the universe undergoes an endless sequence of accelerating-decelerating cycles, driven by the microwave background and supernovae.
Abstract: Recent observations of microwave background and type Ia supernovae (SNe Ia) suggest a space-flat and accelerated expansion Universe. On the other hand, observations of supernovae 1997ff reveal that the Universe has undergone a decelerating-accelerating process. Combining these two classes of observations, we present an eternal expanding Universe toy model driven by quintessence. In this picture, the Universe undergoes an endless sequence of accelerating-decelerating cycles.
1 citations
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TL;DR: In this paper, an axisymmetric rotating universe model with a time dependent factor was investigated and it was concluded that it behaves exactly like a Friedmann model, and they also extended this conclusion to the most general cosmological model.
Abstract: We take an axisymmetric rotating universe model by crossing with a time dependent factor and evaluate its force and momentum in this evolving universe. It is concluded that it behaves exactly like a Friedmann model. We also extend this conclusion to the most general cosmological model.
1 citations
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TL;DR: In this paper, a model of the universe as a self-organized critical system is considered, where the universe evolves to a state independently of the initial conditions at the edge of chaos.
Abstract: A model of the universe as a self-organized critical system is considered. The universe evolves to a state independently of the initial conditions at the edge of chaos. The critical state is an attractor of the dynamics. Random metric fluctuations exhibit noise without any characteristic length scales, and the power spectrum for the fluctuations has a self-similar fractal behavior. In the early universe, the metric fluctuations smear out the local light cones removing the horizon problem.
1 citations