Showing papers on "Big Rip published in 1976"

Observational Tests of Antimatter Cosmologies

Abstract: In approaching the problem of the amount and astrophysical role of antimatter in the Universe, it is valuable to distinguish between two separate questions. First, must the universe be symmetric. Does an application of the microscopic laws of physics to the macroscopic scale of the Universe require that there be exactly equal numbers of particles and antiparticles. In contrast, is the Universe symmetric. The extent to which these questions can be or have been answered is the subject of this review. 2 tables, 118 refs. (GHT)

The curvature of space in a finite universe.

Abstract: The discussion of the curvature of space in a finite universe includes the question of whether the universe is finite or infinite, matter and its properties, models of the galactic system, non-Euclidean geometry, and the structure of space. (JFP)

Will the universe expand forever

Abstract: Plausible cosmological models are examined with respect to measurements of deceleration, the age of the universe, the average density of matter, and the abundance of deuterium. These factors together indicate that the expansion of the universe cannot be halted or reversed, that the universe is open. (BJG)

Quarks in the early Universe

Abstract: The quark theory of hadrons provides a valuable tool for interpreting conditions during early epochs of the Universe. In particular, an asymptotically free theory of quarks seems to rule out the possibility that the present-day entropy of the Universe could be due to dissipation of low level fluctuations. Apparently either the early Universe was inhomogeneous on small mass scales or anisotropic.

Propagators for a scalar field in a homogeneous expanding universe

Abstract: In view of a recent interest in the quantum field-theoretical creation of particles in a big-bang universe (which, via the problem of how their vacuum state should be defined, will be connected with their propagators whose structure depends also on that of the Universe), an attempt is made to derive propagators for a massive scalar field in the Kasner universe.

Cosmological lore—and some heresies

Abstract: Cosmology is based on a number of well-founded assumptions, which include Hubble's law and the cosmological principle. Most cosmologists and astronomers also tacitly accept a number of other assumptions and beliefs which constitute a sort of traditional cosmological lore. Among these are the notions that the universe is finite, that if it is not, then there must be an observational horizon which renders it finite for all practical purposes, that it is valid to employ the special relativistic Doppler formula to interpret large cosmological redshifts, and that the expansion of the universe is slowing down toward its ultimate reversal. It is argued that none of these notions is incontrovertible and that some of them involve serious inconsistencies. An alternative approach is proposed which assumes that the universe is expanding uniformly and that it constitutes a fundamental reference frame for light propagation as implied by the Robertson-Walker metric. This approach leads to a model of the universe which is possibly infinite but without a specific observational horizon, and which satisfies the requirements of relativity. It is shown that the proposed model is theoretically consistent and that recent astronomical evidence supports its assumptions and predictions; it therefore presents a serious challenge to commonly held views about the universe.

On the Hamiltonian treatment of a quantum scalar field in a Bianchi I universe

Abstract: It is shown that with the aid of an Hamiltonian formalism, which is developed, it is possible to treat the problem of a quantum scalar field in a Bianchi I universe of a given metric, taking into account the reaction of the scalar field on the metric itself. Some preliminary calculations show that the process of particle creation, treated within the context of this formalism can account for a large part of the matter content of the universe; it is hoped that subsequent calculations can aid in the problem of the dissipation of the initial anisotropy of the universe. (JFP)

The universe as a Bolyai-Lobachevsky velocity space

Abstract: It is shown that a uniformly-expanding universe, governed by the Cosmological Principle, exhibits a velocity space described by the hyperbolic geometry ofJ. Bolyai andN. Lobachevsky. This geometry provides a mathematical description of the free paths of lightrays and of material bodies, and has considerable theoretical, epistemological and practical implications. Its application is of particular importance for astronomical observations involving cosmological distances; this is exemplified in relation to the estimation of the size of objects (QSOs) with large (z>1) redshifts. It is suggested that Bolyai—Lobachevskian geometry is of general relevance to any expanding model of the universe.