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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, two information number bounds are derived and compared for two types of universe, a universe without a cosmological constant lamda and a universe with one, and the number of information involved in a the two universes are identical or ======N1=N2, and that the total mass of the universe scales as the square root of the information number N, containing an information number n of the order of 10E+122.
Abstract: Bekenstein has obtained is an upper limit on the entropy S, and from that, an information number bound N is deduced. In other words, this is the information contained within a given finite region of space that includes a finite amount of energy. Similarly, this can be thought as the maximum amount of information required to perfectly describe a given physical system down to its quantum level. If the energy and the region of space are finite then the number of information N required in describing the physical system is also finite. In this short letter two information number bounds are derived and compared for two types of universe. First, a universe without a cosmological constant lamda and second a universe with a cosmological constant lamda are investigated. This is achieved with the derivation of two different relations that connect the Hubble constant and cosmological constants to the number of information N. We find that the number of information N involved in a the two universes are identical or
N1=N2, and that the total mass of the universe scales as the square root of the information number N, containing an information number N of the order of 10E+122. Finally, we expressed Calogero quantization action as a function of the number of information N. We also have found that in self gravitating systems the number of information N in nats is the ratio of the total kinetic to total thermal energy of the system.
14 citations
TL;DR: In this article, it was shown that the high value of the speed of light in the early universe was drastically decreased before the beginning of the inflationary period and that the theory of varying speed of time should be questioned as a possible solution of the horizon problem.
Abstract: From an extended relativistic dynamics for a particle moving in a cosmic background field with temperature $T$, we aim to obtain the speed of light with an explicit dependence on the background temperature of the universe. Although finding the speed of light in the early universe much larger than its current value, our approach does not violate the postulate of special relativity. Moreover, it is shown that the high value of the speed of light in the early universe was drastically decreased before the beginning of the inflationary period. So we are led to conclude that the theory of varying speed of light should be questioned as a possible solution of the horizon problem.
14 citations
TL;DR: In this paper, the authors investigate if a recently introduced formulation of general relativity on a Weyl-integrable geometry contains cosmological solutions exhibiting acceleration in the present cosmic expansion.
Abstract: We investigate if a recently introduced formulation of general relativity on a Weyl-integrable geometry contains cosmological solutions exhibiting acceleration in the present cosmic expansion. We derive the general conditions to have acceleration in the expansion of the universe and obtain a particular solution for the Weyl scalar field describing a cosmological model for the present time in concordance with the data combination Planck + WP + BAO + SN.
14 citations
TL;DR: In this article, a cosmological model is proposed to describe the dynamics of life saturating the universe on a cosmic scale, adapting the phase transition model to incorporate probability distributions of expansion and resource consumption strategies, and the authors conclude that the existence of life, if certain advanced technologies are practical, could have a significant influence on the future large-scale evolution of the universe.
Abstract: In the context of a homogeneous universe, we note that the appearance of aggressively expanding advanced life is geometrically similar to the process of nucleation and bubble growth in a first-order cosmological phase transition. We exploit this similarity to describe the dynamics of life saturating the universe on a cosmic scale, adapting the phase transition model to incorporate probability distributions of expansion and resource consumption strategies. Through a series of numerical solutions spanning several orders of magnitude in the input assumption parameters, the resulting cosmological model is used to address basic questions related to the intergalactic spreading of life, dealing with issues such as timescales, observability, competition between strategies, and first-mover advantage. Finally, we examine physical effects on the universe itself, such as reheating and the backreaction on the evolution of the scale factor, if such life is able to control and convert a significant fraction of the available pressureless matter into radiation. We conclude that the existence of life, if certain advanced technologies are practical, could have a significant influence on the future large-scale evolution of the universe.
14 citations
TL;DR: Gabadadze and Shang as mentioned in this paper showed that a spatially-flat de Sitter universe can be created from "nothing", and that the probability to create such a universe is exponentially suppressed.
14 citations