SIZE OF MULTIPLY-CONNECTED UNIVERSE AND COSMIC BACKGROUND RADIATION

1993 ◽  
Vol 08 (28) ◽  
pp. 2615-2621 ◽  
Author(s):  
LI-ZHI FANG
Keyword(s):  
Spherical Harmonic ◽  
Temperature Fluctuation ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Multiply Connected ◽  
Cosmic Background ◽  
Spatial Topology ◽  
Spatial Size ◽  
Topology Of The Universe ◽  
The Universe

A few years ago, we proposed that the spatial topology of the universe can be detected by cosmic background radiation (CBR), because the amplitudes of the spherical harmonic expansion of CBR anisotropy are sensitively dependent on the size of the universe. Recently, this method has been applied to study the size of a T3 universe by using the COBE-DMR data of CBR temperature fluctuation. The new result of the lower limit to the cosmologically spatial size is found to be larger than the old values by a factor of about 5. Therefore, the model of cubic T3 small universe can be ruled out. This paper is a summary of this progress. The significance and remained problems of the spatial topology of the universe have also been discussed.

Cosmology: evidence for a ‘big bang’

1994 ◽  
Vol 2 (2) ◽  
pp. 155-164
Author(s):  
Martin J. Rees
Keyword(s):  
Present State ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Big Bang ◽  
Fundamental Physics ◽  
Cosmic Expansion ◽  
Cosmic Background ◽  
The Universe

During the last 25 years, evidence has accumulated that our universe has evolved, over a period of 10–15 billion years, from a hot dense fireball to its present state. Telescopes can detect objects so far away that the universe had only a tenth its present age when the light we now receive set out towards us. The cosmic background radiation, and the abundances of elements such as helium and lithium, permit quantitative inferences about what the universe was like when it had been expanding for only a few seconds. The laws of physics established in the laboratory apparently suffice for interpreting all astronomical phenomena back to that time. In the initial instants of cosmic expansion, however, the particle energies and densities were so extreme that terrestrial experiments offer no firm guidance. We will not understand why the universe contains the observed ‘mix’ of matter and radiation, nor why it is expanding in the observed fashion, without further progress in fundamental physics.

DENSITY FLUCTUATIONS ON SUPER-HUBBLE SCALES

1996 ◽  
Vol 11 (19) ◽  
pp. 1531-1538 ◽  
Author(s):  
LI-ZHI FANG ◽  
YI-PENG JING
Keyword(s):  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Density Fluctuations ◽  
Cosmic Background ◽  
Density Perturbations ◽  
Hubble Radius ◽  
The Universe

According to causality, the existence of density perturbations on scales larger than the present Hubble radius y = 2c/H0 is crucial to discriminate between inflation and non-inflation models of the origin of inhomogeneity of the universe. Observations of the cosmic background radiation anisotropies favor a super-Hubble suppression on scales λmax in the range 0.5–3.0y. Many of non-inflation models are consistent with such a suppression. Inflation models are certainly not in conflict with this suppression, however one important parameter, the duration of the epoch of inflation, may need to be fine tuned.

scholarly journals DIVISION VIII: GALAXIES AND THE UNIVERSE

2007 ◽  
Vol 3 (T26B) ◽  
pp. 179-180
Author(s):  
Francesco Bertola ◽  
Sadanori Okamura ◽  
Virginia L. Trimble ◽  
Mark Birkinshaw ◽  
Françoise Combes ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Large Scale ◽  
Local Group ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Cosmic Background ◽  
Distant Galaxies ◽  
The Universe

Division VIII gathers astronomers engaged in the study of the visible and invisible matter in the Universe at large, from Local Group galaxies via distant galaxies and galaxy clusters to the large-scale structure of the Universe and the cosmic background radiation.

scholarly journals Large-Angular-Scale Anisotropy in the Cosmic Background Radiation

1980 ◽  
Vol 92 ◽  
pp. 321-328
Author(s):  
George F. Smoot
Keyword(s):  
Solar System ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Spherical Harmonic ◽  
Background Radiation ◽  
Harmonic Component ◽  
Cosmic Background Radiation ◽  
First Order ◽  
Cosmic Background ◽  
Angular Scale

Measurements of the large-angular-scale anisotropy of the cosmic background radiation made from the northern hemisphere are in essential agreement with each other and indicate a first order spherical harmonic component with an amplitude of approximately 3 mK. New data from the southern hemisphere support these previous results. This first order anisotropy is interpreted as resulting from the motion of the solar system relative to the cosmic background radiation. There is no evidence of any higher order anisotropy to the level of 1 mK.

Anisotropy measurements and cosmological implications

1982 ◽  
Vol 307 (1497) ◽  
pp. 67-75 ◽  
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Critical Discussion ◽  
Present Knowledge ◽  
Cosmic Background ◽  
Scale Properties ◽  
The Universe

We summarize the present knowledge of the anisotropies of the cosmic background radiation at angular scales over 1° and present recent data on the dipole and quadrupole harmonics from the Florence group. Reviewing models of cosmic structures, we describe the inferences that can be drawn from the data provided that their origin is extragalactic. We end with a critical discussion of the connection of the background anisotropies with the large-scale properties of the Universe.

BLACK HOLE SINGULARITIES, CRITICAL PHENOMENA, THE RUNAWAY UNIVERSE AND HYPERSPACE TRAVEL

2003 ◽  
Vol 12 (09) ◽  
pp. 1675-1680
Author(s):  
LIOR M. BURKO
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Energy ◽  
Radiation Field ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Radiation Fields ◽  
Cosmic Background ◽  
Expansion Of The Universe ◽  
The Universe

Black holes are always irradiated by the cosmic background radiation. This captured radiation field determines the physical and geometrical nature of the singularity inside the black hole. We find that non-compact radiation fields (similar to the cosmic background radiation) affect dramatically the singularity, and may determine the fate of a falling astronaut. In particular, the dark energy which accelerates the expansion of the universe determines whether the "tunnel" inside the black hole is blocked, or whether the possibility of using the black hole as a portal for hyperspace travel cannot be ruled out as yet.

A NEW VIEW ON THE PROBLEM OF ANISOTROPY OF THE COSMIC BACKGROUND RADIATION

1993 ◽  
Vol 02 (01) ◽  
pp. 97-104 ◽  
Author(s):  
V.G. GURZADYAN ◽  
A.A. KOCHARYAN
Keyword(s):  
Negative Curvature ◽  
Background Radiation ◽  
Cosmological Parameters ◽  
Cosmic Background Radiation ◽  
Geometrical Shape ◽  
Microwave Background ◽  
Cosmic Background ◽  
Microwave Background Radiation ◽  
History Of ◽  
The Universe

The anisotropy properties of the Cosmic Microwave Background Radiation (CMB) are considered within the framework of the photon beam mixing effect developed earlier. The existence of an observable characteristic of the CMB is shown, namely the geometrical shape of anisotropy spots and their degree of complexity, which can contain unique information on cosmological parameters and the life history of the Universe. If future experiments (COBE and others) indicate such features of anisotropy maps, then one can have serious evidence for the negative curvature of the Universe.

scholarly journals Dark Energy and the Riddle of the Cosmological Constant

2021 ◽  
Vol 4 (2) ◽  
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Large Scale ◽  
Background Radiation ◽  
Cosmic Background Radiation ◽  
Average Density ◽  
Astronomical Observations ◽  
Cosmic Background ◽  
Visible Matter ◽  
The Universe

Dark energy was created to interpret astronomical observations that the earlier standard model of cosmology could not explain. First, measurements of the pattern of cosmic background radiation revealed that the universe must be large-scale flat, corresponding to an average density greater than the "dark" and visible matter combined account for.

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