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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 a sketch of the current status of the origin of cosmological structure formation and present two families of models to explain the initial fluctuations: inflationary models and topological defect scenarios.
Abstract: The origin of the large scale structure in the universe - galaxies, quasars, clusters, voids, sheets - is one of the most important questions in cosmology. One can show that some non-thermal energy density fluctuations must have been present in the early universe. These fluctuations grew by gravitational instability to form the observed structures. There are at present two families of models to explain the origin of these initial fluctuations: inflationary models and topological defect scenarios. Current observational developments provide a link with theoretical predictions, allowing us to test our theoretical models. In this contribution, I present a sketch of the current status of the origin of cosmological structure formation.
Journal ArticleDOI
Jan Olof Stenflo1
TL;DR: In this article, the authors show that the observed accelerated expansion that is deduced from the redshifts is an edge effect due to the observer-induced boundary and not representative of the intrinsic evolution.
Abstract: The evolution of the wave function in quantum mechanics is deterministic like that of classical waves. Only when we bring in observers the fundamentally different quantum reality emerges. Similarly the introduction of observers changes the nature of spacetime by causing a split between past and future, concepts that are not well defined in the observer-free world. The induced temporal boundary leads to a resonance condition for the oscillatory vacuum solutions of the metric in Euclidean time. It corresponds to an exponential de Sitter evolution in real time, which can be represented by a cosmological constant $\Lambda =2\pi^2/r_u^2$, where $r_u$ is the radius of the particle horizon at the epoch when the observer exists. For the present epoch we get a value of $\Lambda$ that agrees with the observed value within $2\sigma$ of the observational errors. This explanation resolves the cosmic coincidence problem. Our epoch in cosmic history does not herald the onset of an inflationary phase driven by some dark energy. We show that the observed accelerated expansion that is deduced from the redshifts is an "edge effect" due to the observer-induced boundary and not representative of the intrinsic evolution. The new theory satisfies the BBN (Big Bang nucleosynthesis) and CMB (cosmic microwave background) observational constraints equally well as the concordance model of standard cosmology. There is no link between the dark energy and dark matter problems. Previous conclusions that dark matter is mainly non-baryonic are not affected.
Posted Content
TL;DR: In this article, a review of our knowledge on the distribution of galaxies at large scale, leading to a foam-like large-scale structure of the Universe, is presented in the Introduction, and it is shown how, according to the present theory for the formation of superclusters, wave scalar perturbations of the same frequency traveling in opposite directions give rise to standing waves, which cause a motion of the cosmic material towards the nodes, resulting in the concentration of the material around the nodes.
Abstract: At first, a review of our knowledge on the distribution of galaxies at large-scale, leading to a foam-like large-scale structure of the Universe, is presented in the Introduction. Then, it is shown how, according to the present theory for the formation of superclusters, wave scalar perturbations of the same frequency traveling in opposite directions give rise to standing waves, which cause a motion of the cosmic material towards the nodes, resulting in the concentration of the cosmic material around the nodes. Generalizing this effect to two (three) dimensions, the cosmic material is concentrated around the node lines (node surfaces). It is proposed that the three-dimensional effect is responsible for the foam-like large-scale structure of the Universe.
01 Jan 2014
TL;DR: In this article, a modified model of the Big Bang is proposed taking into account time dilation of gravitational nature occurred in the past, which is responsible for red shift of remote galaxies.
Abstract: On the basis of existence of electromagnetic ether (dark energy) the process of Universe expansion usually named as Big Bang is considered in the paper. It is shown that observable Universe instead of really existing at present moment must be used as a basis of the Universe model. Using spherical Universe approximation the modified model is proposed taking into account time dilation of gravitational nature occurred in the past. It is noted that time dilation in the past is responsible for red shift of remote galaxies. On the basis of the model proposed it is shown that in non-central position of our Galaxy in the Universe the observable Universe must be anisotropic. The empirical time equation of the Universe as exponential dependence Universe intrinsic time on current time is proposed. The assumption is proved that the Universe age is cosmological constant which does not change or changes very slowly. Using time equation as a basis it is shown that expansion of the Universe in units of intrinsic time has started infinitely long ago and proceeds now at permanently increasing speed.
Posted ContentDOI
29 Dec 2022
TL;DR: In this article , a quantum mechanism that could replace the concept of dark matter and energy by considering a primordial curvature as preferred by the PL18 release while yielding the present-day spatial flatness was proposed.
Abstract: Advances in cosmology and astronomical observations over the last two decades have revealed significant tensions and many ambiguities within the standard model of cosmology of a spatially flat Universe, the lambda cold dark matter model. Moreover, the recent Planck Legacy 2018 (PL18) release has confirmed the presence of an enhanced lensing amplitude in the cosmic microwave background (CMB) power spectra, which prefers a positively curved early Universe with a confidence level higher than 99%. This paper addresses the study of a quantum mechanism that could replace the concept of dark matter and energy by considering a primordial curvature as preferred by the PL18 release while yielding the present-day spatial flatness. The implied primordial curvature is incorporated as the background curvature to extend the field equations in terms of the brane-world modified gravity. The Universe evolution is modelled by utilizing a new wavefunction of the Universe that propagates in the bulk with reference to the scale factor of the early Universe and its radius of curvature upon the emission of the CMB, which revealed both positive and negative solutions. This characteristic implies that a pair of entangled wavefunctions was created and evolved in opposite directions as a manifestation of distinct matter and antimatter sides of the Universe. The wavefunction indicates a nascent hyperbolic expansion away from early energy is followed by a first phase of decelerating expansion during the first 10 Gyr, and then, a second phase of accelerating expansion in reverse directions, whereby both sides free-fall towards each other under gravitational acceleration. The predicted background curvature evolution demonstrates the fast orbital speed of outer stars owing to external fields exerted on galaxies as they travelled through earlier conformally curved spacetime. Finally, the wavefunction predicts an eventual phase of rapid spatial contraction that culminates in a Big Crunch, signaling a cyclic Universe. These findings reveal that early plasma could be separated and evolved into distinct sides of the Universe that collectively and geometrically inducing its evolution, physically explaining the effects attributed to dark matter and energy.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202320
202247
20216
202010
201910
201814