OBSERVATIONAL COSMOLOGY 2004: WHAT THE DATA SAY ABOUT DARK ENERGY AND THE CONTENTS OF THE UNIVERSE

2005 ◽  
Vol 20 (14) ◽  
pp. 2931-2942
Author(s):  
JOSEPH FOWLER
Keyword(s):  
Dark Energy ◽  
Background Radiation ◽  
Current Data ◽  
Observational Cosmology ◽  
Microwave Background ◽  
Hubble Expansion ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
Cosmological Data ◽  
The Universe

The latest cosmological data point to a model of the universe that is self-consistent but deeply weird. It seems that most matter in our universe is non-baryonic and hidden from direct view. Meanwhile, a repulsive "dark energy" causes the expansion of the universe to proceed at an accelerating rate. Sources of current data include studies of the distribution of matter in the universe, the anisotropies of the cosmic microwave background radiation, and the Hubble expansion law as probed by distant supernovae. In the near future, we can hope that measurements like these will begin to illuminate the nature of dark energy, starting with the question of whether it behaves like a cosmological constant or shows a more complicated evolution.

scholarly journals Small Scale Fluctuations in the Microwave Background Radiation Associated with the Formation of Galaxies

1977 ◽  
Vol 74 ◽  
pp. 327-334
Author(s):  
R. A. Sunyaev
Keyword(s):  
Spatial Distribution ◽  
Background Radiation ◽  
Gravitational Instability ◽  
Thomson Scattering ◽  
Small Scale ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
The Universe

According to current ideas, massive extragalactic systems such as galaxies and clusters of galaxies formed as a result of the growth of small fluctuations in density and velocity which were present in the early stages of expansion of the Universe under the influence of gravitational instability. According to the hot model of the Universe at the epoch corresponding to a redshift z ≈ 1500, recombination of primaeval hydrogen took place and as a result the optical depth of the Universe to Thomson scattering decreased abruptly from about 1000 to 1 - the Universe became transparent. Therefore the observed angular distribution of the microwave background radiation (MWBR) contains information about inhomogeneities in its spatial distribution at a redshift z ∼ 1000. Silk (1968) was the first to note that this “photograph” of the Universe at the epoch of recombination must be enscribed with fluctuations associated with perturbations in the space density and velocity of motion of matter which will later lead to the formation of galaxies and clusters of galaxies.

scholarly journals Large Scale Anisotropy of the Cosmic Microwave Background

1974 ◽  
Vol 63 ◽  
pp. 157-162 ◽  
Author(s):  
R. B. Partridge
Keyword(s):  
Angular Distribution ◽  
Large Scale ◽  
Background Radiation ◽  
Big Bang ◽  
Microwave Background ◽  
Initial State ◽  
Microwave Background Radiation ◽  
Cosmological Data ◽  
The Big Bang ◽  
The Universe

It is now generally accepted that the microwave background radiation, discovered in 1965 (Penzias and Wilson, 1965; Dicke et al., 1965), is cosmological in origin. Measurements of the spectrum of the radiation, discussed earlier in this volume by Blair, are consistent with the idea that the radiation is in fact a relic of a hot, dense, initial state of the Universe – the Big Bang. If the radiation is cosmological, measurements of both its spectrum and its angular distribution are capable of providing important – and remarkably precise – cosmological data.

scholarly journals ANISOTROPIC DARK ENERGY AND ELLIPSOIDAL UNIVERSE

2011 ◽  
Vol 20 (06) ◽  
pp. 1153-1166 ◽  
Author(s):  
L. CAMPANELLI ◽  
P. CEA ◽  
G. L. FOGLI ◽  
L. TEDESCO
Keyword(s):  
Dark Energy ◽  
Large Scale ◽  
Background Radiation ◽  
Microwave Background ◽  
Anisotropic Dark Energy ◽  
Large Scale Geometry ◽  
Microwave Background Radiation ◽  
Type Ia ◽  
Ia Supernovae ◽  
The Universe

A cosmological model with anisotropic dark energy is analyzed. The amount of deviation from isotropy of the equation of state of dark energy, the skewness δ, generates an anisotropization of the large-scale geometry of the Universe, quantifiable by means of the actual shear Σ0. Requiring that the level of cosmic anisotropization at the time of decoupling be such that we can solve the "quadrupole problem" of cosmic microwave background radiation, we find that |δ| ~ 10-4 and |Σ_0| ~10-5, compatible with existing limits derived from the magnitude redshift data on Type Ia supernovae.

scholarly journals R2 Gravity and the Structure of the Universe

1983 ◽  
Vol 104 ◽  
pp. 483-484
Author(s):  
Kenneth Brecher
Keyword(s):  
Background Radiation ◽  
Big Bang ◽  
Microwave Background ◽  
The Standard Model ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
High Degree ◽  
Cosmological Constants ◽  
The Universe ◽  
Fundamental Physical

The “standard” hot big bang model accounts for the expansion of the Universe, the existence of the microwave background radiation, and the mass fraction of the light elements up to 4He. It does not account for the high degree of isotropy and homogeneity of the Universe in the large, nor of the existence of structure (galaxies, clusters) on smaller scales. Other problems, such as the lepton to baryon ratio, the preponderance of matter over antimatter, and the “coincidences” of dimensionless ratios of several fundamental physical and cosmological “constants” also lie outside of the “standard” model at present.

scholarly journals 2. Anisotropy of the blackbody radiation

1985 ◽  
Vol 19 (1) ◽  
pp. 661-664
Author(s):  
D. T. Wilkinson ◽  
F. Melchiorri
Keyword(s):  
Background Radiation ◽  
Temperature Fluctuations ◽  
Thomson Scattering ◽  
Blackbody Radiation ◽  
Density Fluctuations ◽  
Microwave Background ◽  
Initial Temperature Distribution ◽  
Microwave Background Radiation ◽  
Expansion Of The Universe ◽  
The Universe

The 2.7 K microwave background radiation provides a sensitive probe of the universe in the interesting, but poorly understood, epoch around z ˜ 1000. At this time (age ~ 10 yr) the universe has cooled to T ~ 4000 K, the plasma combines, Thomson scattering ceases, and matter and blackbody radiation decouple. Subsequently, the radiation freely propagates to us, carrying the imprint of temperature fluctuations on the z ~ 1000 surface. The temperature fluctuations could have been caused by primordial density fluctuations, anisotropy in the expansion of the universe, or inhomogeneity in the initial temperature distribution; the z = 1000 surface we see was not causally connected at the time the radiation was released. Interpretation of the anisotropy measurements is complicated by the possibility that the matter may have been reionized (e.g. by massive stars), so the radiation may have been rescattered, possibly as late as z ~ 7.

scholarly journals On Friedman equation, quadratic laws and the geometry of our universe

2021 ◽  
Vol 4 (1) ◽  
pp. 048-050
Author(s):  
Kalimuthu S
Keyword(s):  
General Relativity ◽  
Background Radiation ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Relativistic Jets ◽  
Microwave Background ◽  
Quadratic Equations ◽  
Microwave Background Radiation ◽  
Radio Signals ◽  
Expansion Of The Universe ◽  
The Universe

Einstein’s special and general relativity revolutionized physics. The predictions of general relativity are Strong Lensing, Weak Lensing, Microlensing, Black Holes, Relativistic Jets, A Gravitational Vortex, Gravitational Waves, The Sun Delaying Radio Signals, Proof from Orbiting Earth, Expansion of the universe. The density of the universe determines the geometry and fate of the universe. According to Freedman’s equations of general relativity published in 1922 and 1924, the geometry of the universe may be closed, open and flat. It all depends upon the curvature of the universe also. Various results of Cosmic Microwave Background Radiation (CMBR), NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), and ESA’s Planck spacecraft probes found that our universe is flat within a margin of 0.4% error. In this short work, by applying the laws of quadratic equations, we attempt to show that OUR UNIVERSE IS FLAT.

scholarly journals PROBING THE ANISOTROPIC EXPANSION HISTORY OF THE UNIVERSE WITH COSMIC MICROWAVE BACKGROUND

2012 ◽  
Vol 27 (24) ◽  
pp. 1250144 ◽  
Author(s):  
RANJITA K. MOHAPATRA ◽  
P. S. SAUMIA ◽  
AJIT M. SRIVASTAVA
Keyword(s):  
Cosmic Microwave Background ◽  
Background Radiation ◽  
Microwave Background ◽  
Anisotropic Expansion ◽  
Microwave Background Radiation ◽  
Expansion Stage ◽  
History Of ◽  
Density Perturbations ◽  
Expansion Of The Universe ◽  
The Universe

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 cosmic microwave background radiation (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%.

The Mystery of the Dark Energy Based on Energy Materials

2012 ◽  
Vol 496 ◽  
pp. 523-526
Author(s):  
Jian Guo Lu ◽  
Ming Hu
Keyword(s):  
Dark Energy ◽  
Gamma Ray ◽  
Background Radiation ◽  
Accelerated Expansion ◽  
Energy Materials ◽  
Type Ia Supernova ◽  
Microwave Background Radiation ◽  
Type Ia ◽  
Expansion Of The Universe ◽  
The Universe

Recently the observations on the type Ia supernova has showed the accelerated expansion of the universe which can be used to illustrate by the “dark energy”. In order to understand the accelerated expansion of the universe and the dark energy, people study them based on two aspects: theoretical mechanism and cosmology observation restrictions. The simplest and the most frequently used models of the dark energy are the vacuum energy, cosmic constant model and quintessence model etc. The measurement of the universe can be used to identify the properties of the dark energy. The anisotropy of the type Ia supernova and cosmic microwave background radiation are the methods which commonly used to detect the dark energy, other methods are weak lensing, X ray gas group, high red shift gamma-ray burst and so on

scholarly journals Geodesics and bending of light around a BTZ black hole surrounded by quintessential matter

2021 ◽  
Author(s):  
Shubham Kala ◽  
Hemwati Nandan ◽  
Prateek Sharma ◽  
Maye Elmardi
Keyword(s):  
Black Hole ◽  
Dark Energy ◽  
Background Radiation ◽  
Accelerated Expansion ◽  
Acoustic Oscillations ◽  
Btz Black Hole ◽  
Microwave Background ◽  
Microwave Background Radiation ◽  
Type Ia ◽  
Expansion Of The Universe

Various observations from cosmic microwave background radiation (CMBR), type Ia supernova and baryon acoustic oscillations (BAO) are strongly suggestive of an accelerated expansion of the universe which can be explained by the presence of mysterious energy known as dark energy. The quintessential matter coupled with gravity minimally is considered one of the possible candidates to represent the presence of such dark energy in our universe. In view of this scenario, we study the geodesic of massless particles as well as massive particles around a (2 + 1)-dimensional BTZ black hole (BH) spacetime surrounded by the quintessence. The effect of parameters involved in the deflection of light by such a BH spacetime is investigated in detail. The results obtained are then compared with a usual non-rotating BTZ BH spacetime.

The experience of employment of the mathematical cartography methods in cosmology

2017 ◽  
Vol 923 (5) ◽  
pp. 7-16
Author(s):  
A.V. Kavrayskiy
Keyword(s):  
Background Radiation ◽  
Three Dimensional ◽  
Spherical Coordinates ◽  
Linear Element ◽  
Microwave Background ◽  
Euclidian Space ◽  
Microwave Background Radiation ◽  
Rectangular Coordinates ◽  
The Universe ◽  
Length Distortion

The experience of mathematical modeling of the 3D-sphere in the 4D-space and projecting it by mathematical cartography methods in the 3D-Euclidian space is presented. The problem is solved by introduction of spherical coordinates for the 3D-sphere and their transformation into the rectangular coordinates, using the mathematical cartography methods. The mathematical relationship for calculating the length distortion mp(s) of the ds linear element when projecting the 3D-sphere from the 4-dimensional Euclidian space into three-dimensional Euclidian space is derived. Numerical examples, containing the modeling of the ds small linear element by spherical coordinates of 3D-sphere, projecting this sphere into the 3D-Euclidian space and length of ds calculating by means of its projection dL and size of distortion mp(s) are solved. Based on the model of the Universe known in cosmology as the 3D-sphere, the hypothesis of connection between distortion mp(s) and the known observed effects Redshift and Microwave Background Radiation is considered.

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