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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 paper, a simple technique was proposed to detect any anisotropic expansion stage in the history of the universe starting from the inflationary stage to the surface of last scattering from the CMBR data.
Abstract: We propose a simple technique to detect any anisotropic expansion stage in the history of the universe starting from the inflationary stage to the surface of last scattering from the CMBR data. We use the property that any anisotropic expansion in the universe would deform the shapes of the primordial density perturbations and this deformation can be detected in a shape analysis of superhorizon fluctuations in CMBR. Using this analysis we obtain the constraint on any previous anisotropic expansion of the universe to be less than about 35%.
1 citations
Posted Content•
TL;DR: In this article, a scalar field in a linear potential was proposed to solve the non-local version of the vacuum energy sequestering mechanism by means of scalar fields.
Abstract: We study the proposal to solve the coincidence problem in the non-local version of the vacuum energy sequestering mechanism by means of a scalar field in a linear potential. We show that there is no solution in the theory compatible with observations if one requires the scalar field to drive the present period of acceleration and the collapse.
1 citations
Posted Content•
TL;DR: In this paper, it was shown that the universe before the big bang was a flat rather than a curved region and that the universal attractor of the universe is the same as in the Milne universe.
Abstract: The beautiful scenario of pre-big-bang cosmology is appealling not only because it is more or less derived from string theory, but also because it separates clearly the problem of the initial conditions for the universe from that of high curvatures. Recently, the pre-big-bang program was subject to attack from on the grounds that pre-big-bang cosmology does not solve the horizon and flatness problems in a ``natural'' way, as customary exponential ``new'' inflation does. In particular, it appears that an arbitrarily small deviation from perfect flatness in the initial state can not be accommodated. For this analysis, matter in the universe before the big bang was assumed to be radiation. We perform a similar analysis to theirs, but using the equation of state for ``string matter'' $\rho=-3p$ which seems more appropriate to the physical situation and, also, is motivated by the scale factor duality (in the flat case) with respect to our expanding, radiation dominated, universe. For an open universe we find, exactly, the same time-dependence of the scale factor as in the Milne universe, recently found to represent the universal attractor at $t=-\infty $ of all pre big bang cosmologies. We conclude that our radiation dominated universe comes from a flat rather than a curved region.
1 citations
Posted Content•
TL;DR: In this article, it was shown that the observed diurnal and annual motion of the Earth can just as well be accounted as the diurnal rotation and annual revolution of the universe around the fixed and centered Earth.
Abstract: Using Mach's principle, we will show that the observed diurnal and annual motion of the Earth can just as well be accounted as the diurnal rotation and annual revolution of the Universe around the fixed and centered Earth. This can be performed by postulating the existence of vector and scalar potentials caused by the simultaneous motion of the masses in the Universe, including the distant stars.
1 citations
Journal Article•
TL;DR: In this article, a new model of the observed universe, using solutions to the full Einstein equations, is developed from the hypothesis that our observable universe is an underdense bubble, with an internally inhomogeneous fractal bubble distribution of bound matter systems, in a spatially flat bulk universe.
Abstract: A new model of the observed universe, using solutions to the full Einstein equations, is developed from the hypothesis that our observable universe is an underdense bubble, with an internally inhomogeneous fractal bubble distribution of bound matter systems, in a spatially flat bulk universe. It is argued on the basis of primordial inflation and resulting structure formation, that the clocks of the isotropic observers in average galaxies coincide with clocks defined by the true surfaces of matter homogeneity of the bulk universe, rather than the comoving clocks at average spatial positions in the underdense bubble geometry, which are in voids. This understanding requires a systematic reanalysis of all observed quantities in cosmology. I begin such a reanalysis by giving a model of the average geometry of the universe, which depends on two measured parameters: the present matter density parameter, m, and the Hubble constant, H 0 . The observable universe is not accelerating. Nonetheless, inferred luminosity
1 citations