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We study the Big Rip scenario in Swiss-cheese brane-worlds. The results obtained have been found to be independent of the value of the cosmological constant A whether it is positive, negative, or zero. Negative tension branes are not allowed in the current model. There is a sign flipping in cosmic pressure corresponding to the sign flipping in the deceleration parameter from positive to negative. The evolution of the equation of state parameter shows the presence of three phases: the matter-dominant decelerating era, the accelerated-Quitessence phase, and the phantom phase. The evolution of the potential and kinetic term also shows a change of sign. The energy conditions and cosmographic parameters have also been investigated. Key words: modified gravity, cosmology, dark energy, 1. Introduction and motivation The mysterious dark energy with negative pressure has been introduced as a possible explanation to the accelerating cosmic expansion [1-3]. Some dynamical scalar field models of [...]

We study brane-world models and demonstrate that such models do not admit self-similar solutions through the matter collineation approach. By introducing the hypothesis of variable brane tension, [lambda], we outline the new effective field equation (EFE) in the most simple case (symmetric embedding) under the assumption that the fundamental constants in five dimensions (5D) are constants. In this case, we find the exact form that each physical quantity may take in order that the EFE become invariant under scale transformations. By taking into account such assumptions, we find that in four dimensions the gravitational constant [[kappa].sup.2] ~ [lambda], while the cosmological constant [LAMBDA] ~ [[lambda].sup.2] is always decreasing. These results are quite general and valid for any homogeneous self-similar metric. Nevetheless, the study of the EFE under scale symmetries suggests that [rho] ~ [lambda] (as a functional relationship). This allows us to get a growing [[kappa].sup.2] but, in this case, the fundamental constants in 5D must vary as well. We outline a toy model allowing such a possibility. Key words: brane cosmology, time-varying constants, self-similarity Nous etudions les modeles de monde branaire et demontrons que de tels modeles n'admettent pas de solution autosimilaire par l'approche de collineation de matiere. Introduisant une tension variable branaire, [lambda], nous presentons la nouvelle equation de champ effective (ECE/EFE) dans le cas le plus simple (implantation symetrique) sous l'hypothese que les constantes fondamentales sont constantes en 5D. Dans ce cas, nous trouvons la forme exacte que chaque quantite physique peut prendre de facon a ce que la ECE devienne invariante sous transformation d'echelle. Prenant ceci en compte, nous trouvons en 4D que les constantes gravitationnelle [[kappa].sup.2] ~ [lambda] et cosmologique [LAMBDA] ~ [[lambda].sup.2] sont toujours decroissantes. Ces resultats sont plutot generaux et valides pour toute metrique autosimilaire homogene. Neanmoins, l'etude des ECE sous symetrie d'echelle suggere que [rho] ~ [lambda] (comme relation fonctionnelle). Ceci permet a [[kappa].sup.2] d'etre croissant mais, dans ce cas les constantes fondamentales en 5D doivent egalement varier. Nous presentons un modele jouet qui permet une telle possibilite. [Traduit par la Redaction] Mots-cles : cosmologie branaire, constantes variant dans le temps, solution homothetique, 1. Introduction Recent cosmological observations of Type Ia supernovae (SNIa) at high redshift show evidence of an accelerated expansion of the Universe at late times (see, for instance, refs. [1-3]). [...]

Abstract: How do ontological assumptions in divination shape the structure of the techniques and the way practitioners understand their capacity to know about human fate? In eight signs divination--a birthdate-based [...]

In the present paper, we explore wormholes in [R.sup.2]-gravity within thef(R, T) formalism by using b(r) = [mathematical expression not reproducible] (hybrid shape function). The functional form f(R, T) = R + [alpha][R.sup.2] + [lambda]T is considered where R and T are the Ricci scalar and trace of the energy-momentum tensor, respectively, and a and A are controlling parameters. With the help of the EoS, [omega] = [p.sub.r]/[rho], geometric behavior is analyzed and energy conditions are discussed in the anisotropic scenario. In this investigation, significant contribution of the quadratic geometric term ([R.sup.2]) and linear trace term (T) are shown to validate energy conditions for the specific shape function and analyze wormhole solutions in the absence of exotic matter. Also, we observe that the energy conditions are valid in the whole range (r [greater than or equal to] [r.sub.0]) in the case of constant redshift function with this shape function. Key words: f(R, T) gravity, wormholes, energy conditions, shape function, modified gravity, cosmology. Nous explorons ici les trous de ver en gravite [R.sup.2] a l'interieur du formalisme f(R, T) en utilisant b(r) = [mathematical expression not reproducible] (fonction de forme hybride). Nous retenons la formule f(R, T) = R + [alpha][R.sup.2] + [lambda]T, avec R et T respectivement le scalaire de Ricci et la race du tenseur energie-impulsion, a et A etant des parametres de controle. Avec l'aide de l'equation d'etat (EdE/EoS) [omega] = [p.sub.r]/[rho], nous analysons le comportement geometrique et discutons les conditions sur l'energie dans un scenario anisotrope. Notre examen montre qu'une contribution significative du terme quadratique en R et du terme lineaire en T est necessaire afin de valider les conditions sur l'energie pour des fonctions de forme specifiques et afin d'observer des solutions trous de ver en l'absence de matiere exotique. Nous voyons aussi que les conditions sur l'energie sont valides dans tout le domaine r [greater than or equal to] [r.sub.0] dans le cas d'un decalage vers le rouge constant avec cette fonction de forme. [Traduit par la Redaction] Mots-cles : gravite f(R, T), trous de ver, fonction de forme, conditions sur l'energie, gravite modifiee, cosmologie., 1. Introduction Wormholes are a physical phenomenon that joins two different space-times or two different points on the same space-time. The concept of a wormhole was proposed by Flamm in [...]

Friedmann solutions and higher-dimensional 5D Kaluza-Klein solutions using mathematical packages such as Sagemath and Cadabra are calculated. A modified Friedmann equation powered by loop quantum gravity in higher dimensions is calculated in this work. Loop quantization in extra-dimensional space is predicted. Modified equation of state for non-interacting dark matter and dark energy are calculated. It has been predicted that the higher curvature due to phantom density would be a local kind of quantized curvature. The modified Friedmann solutions with Kaluza-Klein interpretation are found. To achieve a conformal exit, the non-interacting solutions are discussed in this work. The obtained results are compared with the ACDM and quintessence models. The results support conformal cyclic cosmology, which predicts the conformal evolution of the universe without facing any singularity as the result of topological effects. Key words: phantom energy, late time universe, baby universe, scale factor quantization, loop quantum cosmology, Kaluza-Klein cosmology, non-interacting phantom cosmology, conformal cyclic cosmology. Nous utilisons des ensembles logiciels comme Sagemath et Cadabra pour trouver des solutions de Friedmann et de Kaluza-Klein en plus hautes dimensions (5). Sont calculees ici les solutions modifiees de Friedmann sous l'effet d'une gravite quantique a boucles en plus hautes dimensions. Nous predisons une quantification a boucles dans un espace extra-dimensionnel. L'equation d'etat modifiee pour la matiere noire et l'energie sombre sans interaction est calculee et il est predit que la plus haute courbure due a la densite fantome serait une espece locale de courbure quantifiee. Nous trouvons les solutions de Friedmann modifiees avec interpretation Kaluza-Klein. Les solutions sans interaction sont discutees pour realiser la sortie conforme. Les resultats obtenus sont compares avec les modeles ACDM et de quintessence. Notre travail supporte la cosmologie cyclique conforme qui predit l'evolution conforme de l'univers sans aucune singularite comme consequence des effets topologiques. [Traduit par la Redaction] Mots-cles: energie fantome, univers age, univers jeune, quantification du facteur d'echelle, cosmologie quantique a boucles, cosmologie de Kaluza-Klein, cosmologie fantome sans interaction, cosmologie cyclique conforme., 1. Introduction In our previous work, we have investigated the final stages of the universe as conformal cyclic and phantom energy dominated evolution [1]. In that work, we have discovered [...]

In this work, we have considered the Friedmann-Robertson-Walker model of the universe where bounce occurs and the universe is filled with generalized cosmic Chaplygin gas or variable modified Chaplygin gas. We have studied the stability analysis through dynamical system for both models and found the critical points in flat, open, and closed universe. In the presence of a scalar field, the dynamical behavior of scale factor and Hubble parameter is described in both models. Finally, we have analyzed the energy conditions for both the models in bouncing universe. Key words: bouncing universe, dynamical model, scalar field, energy conditions. Nous considerons ici un modele Friedmann-Robertson-Walker d'un univers dans lequel se produit un rebond et qui est rempli d'un gaz de Chaplygin cosmic generalise ou d'un d'un gaz de Chaplygin modifie variable. Nous etudions la stabilite de la dynamique des deux modeles et trouvons les points critiques pour des univers plats, ouverts et fermes. En presence d'un champ scalaire, nous decrivons le comportement du facteur d'echelle et du parametre de Hubble pour les deux modeles. Finalement, nous analysons les conditions sur l'energie pour les deux modeles dans un univers en rebond. [Traduit par la Redaction] Mots-cles : univers en rebond, modele dynamique, champ scalaire, conditions sur l'energie, gaz de Chaplygin., 1. Introduction The initial singularity in the cosmological models is the big problem in the background of General Relativity (GR). The inflation theories suffer from the initial singularity problem [1] [...]

We examine inflation in f(R, [phi]) theory, where a scalar field is coupled to gravity. We have constructed Rf([phi]) models using exponential and power law potentials and study inflation for these models, which can support the early-time acceleration with a useful cosmological constant at high curvature. We have calculated the slow-roll parameters, scalar-to-tensor ratio, and spectral index for these models and analyzed them graphically to check the viability according to recent observational data. We have also presented the evolution of effective equation of state and energy density. Key words:f(R, [phi]) gravity, inflation, slow-roll parameters. Resume: Nous examinons l'inflation dans une theorie f(R, [phi]), ou le champ scalaire est couple a la gravite. Nous construisons les modeles Rf([phi]) en utilisant des potentiels en lois exponentielle et de puissance et nous etudions l'inflation pour ces modeles qui peuvent supporter une acceleration primitive, avec une constante cosmologique utile a courbure elevee. Nous calculons les parametres de roulement lent, le rapport scalaire sur tenseur et l'index spectral pour ces modeles et les analysons graphiquement pour verifier leur viabilite face aux dernieres donnees d'observations. Nous presentons aussi revolution de l'equation d'etat effective et de la densite d'energie. [Traduit par la Redaction] Mots-cles: inflation, parametres de roulement lent, gravite modifiee, energie sombre, physique de l'univers primordial ou primitif., 1. Introduction During the last few years, interest has grown considerably in the early-time expansion of our universe, because of cosmological surveys [1, 2] exploring the cosmic history. The fact [...]

In this work we study wormholes solutions based on fractional action cosmology. We discuss cosmic dynamics of the universe in the presence of wormhole and wormhole wave function in closed Friedmann-Robertson-Walker (FRW) universe. We have observed that cosmic acceleration with traversable wormhole may be realized without the need of exotic matter like dark and phantom energy unless the scale factor of the universe obeys a power law dominated by a negative fractional parameter, which is constrained from type Ia supernovae data. Besides, we have derived wormholes wave function in a closed FRW universe and we have found that a wormhole can survive in the presence of quantum effects only if the expansion of the universe is accelerated with time. Key words: traversable wormholes, Navarro-Frenk-White density profile, fractional Wheeler-DeWitt equation. Nous etudions ici des solutions trou de ver basees sur une cosmologie a action fractionnaire. Nous analysons une dynamique cosmique de l'univers presentant trou de ver et de fonction d'onde de trou de ver dans un univers FRW. Nous observons que l'acceleration cosmique avec trou de ver franchissable peut exister sans avoir recours a de la matiere exotique comme la matiere noire ni a une energie fantome, a moins que le facteur d'echelle de l'univers n'obeisse a une loi de puissance dominee par un parametre fractionnaire negatifdont la valeur est contrainte par les donnees SNe Ia. De plus, nous obtenons des fonctions d'onde de trou de ver dans un univers FRW ferme et nous trouvons qu'un trou de ver peut survivre en presence d'effets quantiques seulement si l'expansion de l'univers accelere avec le temps. [Traduit par la Redaction] Mots-cles : trou de ver franchissable, profil de densite de Navarro-Frenk-White, equation fractionnaire de Wheeler-DeWitt, fonction d'onde, expansion acceleree., 1. Introduction Wormholes are usually defined as connecting two different space-times with two different topologies and operating at the Planck scale, which are useful to understand black hole evaporation in [...]

We study the classical flat full causal bulk viscous Friedmann-Robertson-Walker cosmological model with variable gravitational and cosmological constants through the factorization method. The method allows us to find some new exact parametric solutions. The assumptions made lead us to study two approaches. We find, in the studied cases, that the Universe ends in an accelerating era except in the case of a particular solution where the Universe could be noninflationary for all times. In both approaches the cosmological constant is a decreasing function of time, while the gravitational constant behaves as a growing or decreasing time function depending on the sign of A. By taking into account recent observations that indicate that A must be positive, we conclude that G increases with time except in the first solution where both 'constants' tend asymptotically in the large time limit to a constant value. We also present a new factorization scheme that allows us to generate new solutions to a kind of variable-coefficient, nonlinear, second-order, ordinary differential equation. Key words: full causal bulk viscosity, FRW cosmologies, time-varying constants, factorization method, exact solutions. Nous utilisons la methode de factorisation pour etudier le modele cosmologique FRW classique a viscosite volumique et completement causal, dote de constantes gravitationnelle et cosmologiques variables. La methode permet de trouver de nouvelles solutions parametriques exactes. Nos hypotheses nous amenent a etudier deux approches. Dans les cas etudies, nous trouvons que l'univers finit dans une phase acceleree, sauf dans le cas particulier ou l'univers pourrait ne jamais connaitre de phase d'acceleration. Dans les deux approches, la constante cosmologique decroit avec le temps, alors que la constante gravitationnelle croit ou decroit avec le temps selon le signe de A. Tenant compte des recentes observations qui suggerent que A est positif, nous concluons que G doit croitre avec le temps, excepte dans la premiere solution ou les deux constantes tendent asymptotiquement vers des valeurs constantes dans la limite des temps tres grands. Nous presentons egalement un nouveau schema de factorisation qui permet de generer de nouvelles solutions a une sorte d'equation differentielle ordinaire du second ordre non lineaire a coefficient variable. [Traduit par la Redaction] Mots-cles: (modele) a viscosite volumique completement causal, cosmologies FRW, constantes variant dans le temps, methode de factorization, solutions exactes., 1. Introduction The distribution of matter can be satisfactorily described by a perfect fluid due to the large scale distribution of galaxies in our universe. However, observed physical phenomena, such [...]

Author(s): R. Genzel (corresponding author) [1, 2]; N. M. Frster Schreiber (corresponding author) [1]; H. bler [1]; P. Lang [1]; T. Naab [3]; R. Bender [1, 4]; L. J. Tacconi [...]

In this paper, we discuss the tensor mode perturbation in the frame of loop quantum cosmology with higher order holonomy corrections. We get the dynamics of the background near the bounce and far from the bounce. Based on the solutions of the effective Friedmann equation, we deduce the effective gravitational wave equation and get the quantum corrections in both the mass term and source term. We solve the gravitational wave equation near the bounce and discuss the situation far from the bounce. We also find the new terms arose only when one considers the higher order corrections. Key words: loop quantum cosmology, higher order holonomy corrections, tensor mode perturbation, effective Friedmann equation, gravitational wave. Nous discutons ici la perturbation tensorielle dans le cadre de la cosmologie quantique a boucles avec corrections d'holonomie d'ordre eleve. Nous obtenons la dynamique du fond, pres et loin du rebond. Sur la base des solutions de l'equation effective de Friedmann, nous deduisons l'equation d'onde gravitationnelle effective et obtenons les corrections quantiques dans les termes de masse et de source. Nous solutionnons l'equation d'onde gravitationnelle pres du rebond et discutons la situation loin du rebond. Nous trouvons egalement les nouveaux termes qui apparaissent seulement en tenant compte des corrections d'ordre plus eleve. [Traduit par la Redaction] Mots-cles : cosmologie quantique a boucles, corrections d'holonomie d'ordre plus eleve, perturbation tensorielle, equation effective de Friedmann, onde gravitationnelle., 1. Introduction Currently, the problem of finding a quantum theory of the gravitational field is still open. One candidate theory is loop quantum gravity [1-3], which is a mathematically well-defined, [...]

The entropic cosmology model is an alternative method to explain the accelerated expansion of the universe. In this paper, we discuss the dynamical system in two types of entropic cosmology model: Λ(t) type and bulk viscous type. We found that the stability properties of fixed points are affected by the [H.sup.2] term, while the H term and constant term have no influence on stability properties of fixed points. We also found that the dynamical properties of the C-version model are the same as the H-version model. Key words: entropic cosmology, dark energy, dynamical system. Le modele de cosmologie entropique presente une methode alternative pour expliquer l'expansion acceleree de l'univers. Nous etudions ici le systeme dynamique dans deux modeles de cosmologie entropique, le type A(t) et le type BV. Nous trouvons que la stabilite des points fixes est affectee par le terme [H.sup.2], alors que les termes H et constant n'ont aucun effet sur la stabilite des points fixes. Nous trouvons egalement que les proprietes dynamiques du modele en version C sont les memes que celles du modele en version H. [Traduit par la Redaction] Mots-cles: cosmologie entropique, energie somber, systeme dynamique. PACS Nos.: 98.80.-k, 95.36.+x., 1. Introduction Observations indicate that the expansion rate of the universe is accelerating [1-5]. There are several methods to explain the accelerated expansion of the late universe [6]. The most [...]

In this paper, we discuss Einstein's field equations for a spatially homogeneous and anisotropic Bianchi type-V space-time in the presence of a perfect fluid and heat conduction. We obtain exact solutions of the field equations by applying the hybrid expansion law for the average scale factor that yields power-law and exponential-law cosmologies in its special cases. We observe that the universe exhibits a transition from deceleration to acceleration in its expansion. The universe is anisotropic at the early stages of its evolution and becomes isotropic at late time. At late time dark energy dominates, leading to accelerated expansion of the universe. The physical and kinematical behaviors of the model are also discussed. PACS Nos.: 04.20-q, 04.20.Jb, 98.80.-k. Nous discutons ici des equations de champ d'Einstein pour un espace-temps de Bianchi de type V spatialement homogene et anisotrope, en presence d'un fluide parfait et de conduction de chaleur. Nous obtenons des solutions exactes des equations de champ en utilisant une loi d'expansion hybride pour le facteur d'echelle moyen qui donne des cosmologies en loi de puissance et en loi exponentielle dans les cas speciaux. Nous observons que l'univers subit une transition d'une phase de deceleration vers une phase d'acceleration. L'univers initialement anisotrope tend vers un etat isotrope avec le temps, alors que l'energie sombre vient a dominer pour accelerer l'expansion de l'univers. Nous analysons les proprietes physiques et cinematiques du modele. [Traduit par le Redaction], 1. Introduction We investigate a Bianchi type-V spatially homogeneous and anisotropic cosmological model when the source of the gravitational field is a perfect fluid and heat conduction. It is certainly [...]

In this paper we study the loop quantum effects on the Om diagnostic and subsequently on the universe. We reconstruct the Om diagnostic in the background of loop quantum gravity [...]

Despite the unknown nature of the dominant components, the ΛCDM paradigm successfully describes the evolution of the Universe from its near-uniform early state, as measured by the cosmic microwave background [...], A principal discovery in modern cosmology is that standard model particles comprise only 5 per cent of the mass-energy budget of the Universe. In the ACDM paradigm, the remaining 95 per cent consists of dark energy (Λ) and cold dark matter. ΛCDM is being challenged by its apparent inability to explain the low-density 'cores' of dark matter measured at the centre of galaxies, where centrally concentrated high-density 'cusps' were predicted. But before drawing conclusions, it is necessary to include the effect of gas and stars, historically seen as passive components of galaxies. We now understand that these can inject heat energy into the cold dark matter through a coupling based on rapid gravitational potential fluctuations, explaining the observed low central densities.

A ghost dark energy model has been recently put forward to explain the current accelerated expansion of the universe. In this model, we develop the general scheme for modified f(R) gravity reconstruction from realistic anisotropic Bianchi type I cosmology. Power-law volumetric expansion is used to obtain exact solutions of the field equations. We discuss the physical behavior of the solutions and anisotropy behavior of the fluid, the expansion parameter, and the model in future evolution of the universe. We reconstruct corresponding f(R) gravities and obtain the equation of state parameter. We show that the corresponding f(R) gravity of the ghost dark energy model can behave like phantom or quintessence of the selected models that describe accelerated expansion of the universe. PACS Nos.: 95.36.+x, 04.60.Pp. On a recemment mis de l'avant un modele d'energie sombre fantome pour expliquer l'actuelle acceleration de l'expansion de l'univers. Dans ce modele, nous developpons un schema general pour la reconstruction de la gravite f(R) modifiee a partir d'une cosmologie anisotrope realiste de Bianchi de type I. Nous utilisons une expansion volumique en loi de puissance afin d'obtenir des solutions exactes des equations de champ. Nous discutons du caractere physique de la solution et du caractere anisotrope du fluide, du parametre d'expansion et du modele dans une evolution future de l'univers. Nous reconstruisons les gravites f(R) correspondantes et obtenons l'equation du parametre d'etat. Nous montrons que la gravite f(R) correspondant au modele d'energie sombre fantome peut se comporter comme le fantome ou la quintessence des modeles selectionnes qui decrivent l'expansion acceleree de l'univers. [Traduit par la Redaction], 1. Introduction The probable presence of an unknown form of energy in the universe, called dark energy (DE), confirmed by a large number of observations, starting by the data of [...]

On the first night of January of 1494, while transporting a load from Gallipoli to Edirne with other fellow laborers, a wagon driver had an accident in Bolayir. When his [...]

Levi ben Gerson (Gersonides: 1288-1344) included discussions of cosmology in his magnum opus on astronomy (Wars of the Lord, Book V, Part 1). In particular, he addressed issues concerning the arrangement of the planets and their orbs in space. In chapter 29 of this work, Levi argues that the lowest of the set of orbs for each planet moves with the daily rotation and that the planet itself lies on the highest of its set of orbs. He claims that observations of certain phenomena visible in the sky provide evidence for his view and quotes a passage from Book II of Ptolemy's Planetary Hypotheses in support of the principle that the surrounding orb is moved by the orb it encloses. Although Levi took Ptolemy's work as his point of departure, he developed his own theories, which display considerable innovation. An edition of chapter 29 (based on three Hebrew manuscripts), with an English translation, is presented here., Introduction The astronomical works of Levi ben Gerson (Gersonides: 1288-1344) have received considerable attention in recent years. (1) In this paper we focus on his cosmology rather than on his [...]

This paper is mainly concerned with the reception of the theory of a starless ninth orb by Maimonides (1138-1204). Maimonides addressed this topic in two of his works: first, in the third chapter of the Laws of the Foundation of the Torah, part of his code of Jewish law, the Mishneh Torah; and, at a later date, in the Guide of the Perplexed. I begin with the approach to the ninth orb in the Laws of the Foundation of the Torah, where it is presented as a starless orb divided into twelve signs named for the twelve zodiacal constellations. My contention is that Maimonides extracted the ideas about the ninth orb from a cosmological work ascribed to Masha'allah, an early Abbasid astrologer, or from some later work derived from Masha'allah's cosmology. I also clarify the unusual features of this model as presented by Masha'allah and try to determine the rationale behind its inclusion in Masha'allah's cosmology as well as in Maimonides' Mishneh Torah. This, I maintain, has to do not only with cosmological but also and especially with astrological considerations. Then I briefly study the approach to the ninth orb in the Guide, where it is incorporated in its 'classical' form, i.e., as the all-encompassing orb imparting the diurnal motion to all the other motions, and weigh the difference between this and the Mishneh Torah. Last, in a short postscript, I broaden the scope to show that Masha'allah's cosmology, particularly the ninth starless orb divided into twelve signs, was widely known in the Arabic world before Maimonides, especially among Jewish intellectuals in Muslim Spain., In ancient and medieval cosmologies, structured around nested or concentric orbs, the problem of determining the number of these orbs and identifying the outermost orb held a strong appeal for [...]

ISAAC NEWTON'S UNIVERSE was a cozy, tidy place. Gathered around the sun were six planets, a handful of moons and the occasional comet, all moving against a backdrop of stationary [...]

The 'Sun and the Shakers, Again' resumes the conversation begun by Mervyn J. Meggitt in his 1973 article 'The Sun and the Shakers' concerning the circumstances and mindset of Enga and Ipili speakers on the eve (or in the early stages) of colonial penetration. The 'Cult of Ain,' as Meggitt termed a regional cult that broke out in the mid-1940s, followed on the heels of devastating epidemics and famine and was in some measure, at least in most areas where it caught on, a response to those traumas. Yet there were other dimensions: apparent cargo cultism and millenarianism. Widening the geographical scope of reporting beyond that of Meggitt's article to include both the Somaip, as reported on by Hans Reithofer in The Python Spirit and the Cross, and the Ipili speakers of the western Porgera valley and the Paiela valley, this second and final installment reviews and critiques existing interpretations of the Cult of Ain in light of the ethnohistorical detail offered in the first installment and goes on to offer an interpretation of the cult that is inspired by the cosmological symbols common to all cult versions: most obviously the sun but also the sky. The Cult of Ain is viewed by participants and their descendants alike as the prelude to colonialism and missionization, and understanding it is crucial to writing the cultural history of the last 65+ years. Keywords: New Guinea, western highlands, cultural history, cosmology, first contact, INTERPRETING THE CULT OF AIN Meggitt's explanation for the cult remains foundational and indispensable to all subsequent writings on it. '... the frequency with which the epidemics of the early [...]

In this paper, we study the curvaton reheating mechanism for an intermediate inflationary universe in brane world cosmology. In contrast to our previous work, we assume that when the universe enters the kination era, it is still in the high-energy regime. We then discuss, in detail, the new cosmological constraints on both the model parameters and the physical quantities. PACS Nos: 98.80.Cq, 11.25.-w Nous etudions ici le mecanisme de rechauffe pour un univers inflationniste intermediate en cosmologie d'un monde branaire. Contrairement a notre travail precedent, nous supposons qu'au moment d'entrer dans son ere cinetique, l'univers est encore en regime de haute energie. Nous discutons en detail les nouvelles contraintes cosmologiques sur les parametres du modele et sur les quantites physiques. [Traduit par la Redaction], 1. Introduction Inflation, as the most promising framework for understanding the physics of the very early universe, ties the evolution of the universe to the properties of one or more [...]

This document briefly outlines some of the issues pertinent to early inflation and how they affect strain readings for a GW detector, GW wavelengths, and the number of gravitons which may be collected per phase space, among other issues. Different inflation models will also be briefly explored to.explain in part rates of wavelength alterations of GW's from their pre-inflation genesis to inflationary generation. We also describe a standard for GW measurement and how the 'metric' of measurement varies between the different cosmological models, thereby allowing them to be distinguished epxerimentally. The best chances for relic GW measurements are within the 01Hz < f < 10 GHz range according to the pre big bang models and the QIM model. Conventional red shift calculations indicate that past the big bang massive red shifting continues and would eliminate HFGW as presently measurable from the big bang. If there are still in the present day HFGW detectable from the big bang, then we have either an absence of extreme post big bang red shifting, inflation as configured is not quite what we think in the initial inflationary era, or there are even higher frequency GW generated in the onset of creation. Keywords: strain, wavelength, gravitons, entropy, Introduction Historical remarks: the fundamental issue of relic gravitational waves was introduced in the literature by the paper L.P. Grishchuk,[1] and as an inflationary scenario in A. A. Starobinsky,[2] The [...]

In this paper, we investigate the validity of the generalized second law of thermodynamics in flat Friedmann-Lemaitre-Robertson-Walker chameleon cosmology where the boundary of the universe is assumed to be enclosed by the dynamical apparent horizon. It has been shown that, in a bouncing scenario for the universe with phantom crossing, the total entropy decreases with time in the contracting epoch, whereas, the dynamics of the internal and horizon entropies depend on the behaviour of both the equation of state and the Hubble parameters. PACS Nos: 04.50.h, 04.50.Kd Nous etudions ici la validite de la deuxieme loi generalisee de la thermodynamique dans une cosmologie cameleon Friedmann-Lemaitre-Robertson-Walker plate, ou la frontiere de l'univers est supposee bornee par l'horizon apparent dynamique. Il a ete demontre que, dans le scenario du rebond avec croisement vers le fant?me, l'entropie totale diminue avec le temps pendant la periode de contraction, alors que la dynamique des entropies, interne et de l'horizon, depend a la fois de l'equation d'etat et des parametres de Hubble. [Traduit par la Redaction], 1. Introduction Motivated by black hole physics, it was realized that there is a profound connection between gravity and thermodynamics. In Einsteinian gravity, the evidence of this connection was first [...]

We have studied the curvaton scenario in brane world cosmology in an intermediate inflationary scenario. This approach has allowed us to find some constraints on different parameters that appear in the model. PACS Nos: 98.80.Cq, 11.25.-w Resume : Nous etudions le scenario de courbure dans une cosmologie de brane dans un scenario inflationniste intermediaire. Cette approche nous a permis de deecouvrir certaines contraintes sur les differents parametres qui apparaissent dans le modele. [Traduit par la Redaction], 1. Introduction Inflation, as the most promising framework for understanding the physics of the very early universe, ties the evolution of the universe to the properties of one or more [...]

Current efforts in observational cosmology are focused on characterizing the mass-energy content of the universe. We present results from a geometric test based on strong lensing in galaxy clusters. Based on Hubbie Space Telescope images and extensive ground-based spectroscopic follow-up of the massive galaxy duster Abell 1689, we used a parametric model to simultaneously constrain the duster mass distribution and dark energy equation of state. Combining our cosmological constraints with those from x-ray dusters and the Wilkinson Microwave Anisotropy Probe 5-year data gives [[OMEGA].sub.m] = 0.25 [+ or -] 0.05 and [W.sub.x] = [+ or -] 0.97 [+ or -] 0.07, which are consistent with results from other methods. Inclusion of our method with all other available techniques brings down the current 2[sigma] contours on the dark energy equation-of-state parameter [W.sub.x] by ~30%. 10.1126/science.1185759

The observation of primordial gravitational waves could provide a new and unique window on the earliest moments in the history of the universe and on possible new physics at energies many orders of magnitude beyond those accessible at particle accelerators. Such waves might be detectable soon, in current or planned satellite experiments that will probe for characteristic imprints in the polarization of the cosmic microwave background, or later with direct space-based interferometers. A positive detection could provide definitive evidence for inflation in the ear[y universe and would constrain new physics from the grand unification scale to the Planck scale. doi: 10.1126/science.1179541

We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy.

A common belief about big-bang cosmology is that the cosmological redshift cannot be properly viewed as a Doppler shift (that is, as evidence for a recession velocity) but must be viewed in terms of the stretching of space. We argue that, contrary to this view, the most natural interpretation of the redshift is as a Doppler shift, or rather as the accumulation of many infinitesimal Doppler shifts. The stretching-of-space interpretation obscures a central idea of relativity, namely that it is always valid to choose a coordinate system that is locally Minkowskian. We show that an observed frequency shift in any spacetime can be interpreted either as a kinematic (Doppler) shift or a gravitational shift by imagining a suitable family of observers along the photon's path. In the context of the expanding universe, the kinematic interpretation corresponds to a family of comoving observers and hence is more natural. [DOI: 10.1119/1.3129103]

The standard [LAMBDA]CDM model of cosmology is usually understood to arise from demanding that the Friedmann-Lemaitre-Robertson-Walker (FLRW) metric satisfy the General Relativity dynamics for spacetime metrics. The supernovae red-shift data give the FLRW parameter values, [[OMEGA].sub.[LAMBDA]] = 0.73 and [[OMEGA].sub.m] = 0.27 for the dark energy and dark matter+matter content of the universe. When extended to galactic rotations and cosmology Newtonian dynamics is found to be wanting, and the fix-up involves introducing dark matter and dark energy. A different theory of gravity leads to a different account of galactic rotations and cosmology, and does not require dark matter nor dark energy to fit the supernova data. It is shown that fitting the [LAMBDA]CDM model to this new model, and so independently of the actual supernova data, requires the [LAMBDA]CDM model parameters to be those given above. Hence we conclude that dark energy and dark matter are no more than artifacts to fix-up limitations of Newtonian gravity., 1 Introduction The current [LAMBDA]CDM standard model of cosmology is based upon General Relativity (GR) as applied to the spatially-flat Friedmann-Lemaitre-Robertson-Walker (FLRW-GR) spacetime metric together with the Weyl postulate for [...]

This article is an expanded version of a talk given at the International Symposium Celebrating the 100th Birthday of Kurt Godel (Vienna, 2006). It seeks to trace the path which led this preeminent mathematical logician to discover one of the famous results of General Relativity, the rotating Godel Universe. This universe has some remarkable properties, which gave the philosophers plenty to worry about. It allows a person to travel into his own past, with all the ensuing causal paradoxes; it allows no unique temporal ordering of events; and though Godel's Universe is rigid and infinite, the Foucault pendulum planes everywhere in it rotate in unison, a clear affront to adherents of Mach's Principle. We also discuss some lesser known precursors in the field, who just missed discovering Godel's universe. While the article gives all the necessary derivations in simplified form (for example, of the metric and its geodesics), much of it should be accessible to the general reader, who can simply skip most of the mathematics. [DOI: 10.1119/1.3086933]

The formation of the first stars and galaxies at the end of the cosmic 'dark ages' is one of the central problems in modern cosmology (1-3). It is thought that [...], Observations made using large ground-based and space-borne telescopes have probed cosmic history from the present day to a time when the Universe was less than one-tenth of its present age. Earlier still lies the remaining frontier, where the first stars, galaxies and massive black holes formed. They fundamentally transformed the early Universe by endowing it with the first sources of light and chemical elements beyond the primordial hydrogen and helium produced in the Big Bang. The interplay of theory and upcoming observations promises to answer the key open questions in this emerging field.

Assuming that the Universe is spatially infinite, we depict a simple model where gravitation does not decelerate the expansion, which occurs at constant speed for any two distant galaxies. This Steady Flow model fits the SNe Ia observations without a repulsive dark energy. We review the main problems of Big Bang cosmology and see how they can be solved. Particularly, the singularity and the problem of the cosmic origin could be avoided in our framework. The time evolution of the scale factor (R [proportional] t) leaves a longer period for early structure and galaxy formation. However, the expansion time coincides with the Universe age of the standard model. Other features of Big Bang, such as the evolution of temperature with the scale factor and the primordial nucleosynthesis, remain unchanged. Keywords: Cosmology, Type Ia supernovae, Early Universe, Primordial nucleosynthesis, 1. Introduction Centuries ago, Newton postulated the idea of an infinite Universe in order to avoid the stars falling into a hypothetical centre of mass of a finite space. For [...]

The cosmological Robertson-Walker metric of general relativity is often said to have the consequences that (1) the recessional velocity v of a galaxy at proper distance e obeys the Hubble law v =Hl, and therefore galaxies at sufficiently great distance e are receding faster than the speed of light c; (2) faster than light recession does not violate special relativity theory because the latter is not applicable to the cosmological problem, and because 'space itself is receding' faster than c at great distance, and it is velocity relative to local space that is limited by c, not the velocity of distant objects relative to nearby ones; (3) we can see galaxies receding faster than the speed of light; and (4) the cosmological redshift is not a Doppler shift, but is due to a stretching of photon wavelength during propagation in an expanding universe. We present a particular Robertson-Walker metric (an empty universe metric) for which a coordinate transformation shows that none of these interpretation necessarily holds. The resulting paradoxes of interpretation lead to a deeper understanding of the meaning of the cosmological metric. [DOI: 10.1119/1.2987790]