On Multiple Images in Closed Universes
نویسنده
چکیده
Universes with multiconnected spatial sections predict multiple images of cosmic sources. A confusing terminology exists in the naming of these images as real ones vs. ghosts. Here an attempt is made to clarify the situation.
منابع مشابه
Sources of CMB Spots in Closed Hyperbolic Universes
The results of a previous paper by the author [Astrophys. J. 470, 43 (1996)] are improved, through a more reliable technique for finding the location of sources whose images are on the surface of last scattering. Typeset using REVTEX
متن کاملThe Ups and Downs of Cyclic Universes
We investigate homogeneous and isotropic oscillating cosmologies with multiple fluid components. Transfer of energy between these fluids is included in order to model the effects of non-equilibrium behavior on closed universes. We find exact solutions which display a range of new behaviors for the expansion scale factor. Detailed examples are studied for the exchange of energy from dust or scal...
متن کاملOpen and closed universes, initial singularities, and inflation.
The existence of initial singularities in expanding universes is proved without assuming the timelike convergence condition. The assumptions made in the proof are ones likely to hold both in open universes and in many closed ones. (It is further argued that at least some of the expanding closed universes that do not obey a key assumption of the theorem will have initial singularities on other g...
متن کاملCosmic Crystallography in Compact Hyperbolic Universes
We try to apply the cosmic crystallography method of Lehoucq, Lachieze-Rey, and Luminet to a universe model with closed spatial section of negative curvature. But the sharp peaks predicted for Einstein-de Sitter closed models do not appear in our hyperbolic example. So we turn to a variant of that method, by subtracting from the distribution of distances between images in the closed model, the ...
متن کاملMulti-granulation fuzzy probabilistic rough sets and their corresponding three-way decisions over two universes
This article introduces a general framework of multi-granulation fuzzy probabilistic roughsets (MG-FPRSs) models in multi-granulation fuzzy probabilistic approximation space over twouniverses. Four types of MG-FPRSs are established, by the four different conditional probabilitiesof fuzzy event. For different constraints on parameters, we obtain four kinds of each type MG-FPRSs...
متن کامل