scholarly journals COSMOLOGICAL CONSTRAINTS FOR THE COSMIC DEFECT THEORY

2011 ◽  
Vol 20 (06) ◽  
pp. 1039-1051 ◽  
Author(s):  
NINFA RADICELLA ◽  
MAURO SERENO ◽  
ANGELO TARTAGLIA
Keyword(s):  
Large Scale ◽  
Hubble Constant ◽  
Big Bang ◽  
Nuclear Species ◽  
Type Ia ◽  
Species Abundances ◽  
Age Of The Universe ◽  
Ia Supernovae ◽  
The Big Bang ◽  
The Universe

The cosmic defect theory has been confronted with four observational constraints: primordial nuclear species abundances emerging from the big bang nucleosynthesis; large scale structure formation in the Universe; cosmic microwave background acoustic scale; luminosity distances of type Ia supernovae. The test has been based on a statistical analysis of the a posteriori probabilities for three parameters of the theory. The result has been quite satisfactory and such that the performance of the theory is not distinguishable from that of the ΛCDM theory. The use of the optimal values of the parameters for the calculation of the Hubble constant and the age of the Universe confirms the compatibility of the cosmic defect approach with observations.

scholarly journals The Hubble Constant

2000 ◽  
Vol 17 (1) ◽  
pp. 45-47 ◽  
Author(s):  
Jeremy Mould
Keyword(s):  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Hubble Constant ◽  
Big Bang ◽  
Accelerating Universe ◽  
De Sitter ◽  
Age Of The Universe ◽  
Extragalactic Distance Scale ◽  
The Big Bang ◽  
The Universe

AbstractWith the completion of the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale, it is interesting to form the dimensionless quantity H0t0 by multiplying the Hubble Constant by the age of the Universe. In a matter dominated decelerating Universe with a density exceeding 0·26 of the critical value, H0t0 < 1; in an accelerating Universe with the same Ωm = 0·26, but dominated by vacuum energy with ΩV ≥ 1 – Ωm, H0t0 ≥ 1. If the first globular clusters formed 109 years after the Big Bang, then with 95% confidence H0t0 =1·0 ± 0·3. The classical Einstein–de Sitter cosmological model has H0t0 = ⅔.

scholarly journals Resolving Hubble tension with the Milne model

2020 ◽  
Vol 29 (14) ◽  
pp. 2043025
Author(s):  
Ram Gopal Vishwakarma
Keyword(s):  
Hubble Constant ◽  
Big Bang ◽  
New Physics ◽  
Late Time ◽  
Standard Cosmology ◽  
Evolution Dynamics ◽  
Age Of The Universe ◽  
The Big Bang ◽  
The Universe ◽  
Big Bang Singularity

The recent measurements of the Hubble constant based on the standard [Formula: see text]CDM cosmology reveal an underlying disagreement between the early-Universe estimates and the late-time measurements. Moreover, as these measurements improve, the discrepancy not only persists but becomes even more significant and harder to ignore. The present situation places the standard cosmology in jeopardy and provides a tantalizing hint that the problem results from some new physics beyond the [Formula: see text]CDM model. It is shown that a nonconventional theory — the Milne model — which introduces a different evolution dynamics for the Universe, alleviates the Hubble tension significantly. Moreover, the model also averts some long-standing problems of the standard cosmology, for instance, the problems related with the cosmological constant, the horizon, the flatness, the Big Bang singularity, the age of the Universe and the nonconservation of energy.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.

Big Bang Theory

2018 ◽  
Author(s):  
Matthew Y. Heimburger
Keyword(s):  
Large Scale ◽  
Mechanistic Model ◽  
Albert Einstein ◽  
Physical World ◽  
Big Bang ◽  
Scientific Model ◽  
Social Sciences And Humanities ◽  
Big Bang Theory ◽  
The Big Bang ◽  
The Universe

The Big Bang theory is a scientific model of the universe that posits a state of dense, centralized matter before the current, observable expansion of the universe in one giant explosion. While ‘the Big Bang’ was a phrase first used somewhat facetiously by British astronomer Fred Hoyle in 1949, it rested on earlier theories and observations by George Lamaitre, Albert Einstein, and Edwin Hubble. The implications of Big Bang theory have been far-reaching. For some, the Big Bang’s suggestion of a ‘beginning of time’ lent itself to familiar religious teleology. For others, it provided a rigid, mechanistic model of the physical world, which in turn affected ideas in the social sciences and humanities. This is not to say that Big Bang theory was a ‘grand unifying theory’—even in the 1920s, the rather precise predictions of Einstein’s theories of relativity conflicted with the conclusions of Heisenberg’s Uncertainty Principle and quantum mechanics. Still, the idea that the physical world exists due to the violent expansion (and subsequent contraction) of matter suggests a rather small place for humanity in the larger scheme of things. There is little room or need for free will in such a system—at least when it comes to matters of large-scale significance. Today, the Big Bang often stands as a euphemism for debates over God and human determinism in the universe, and lends itself to philosophic traditions such as nihilism and existentialism.

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 Tempeature Redshift of Photons

2020 ◽  
Author(s):  
Xiaoping Hu
Keyword(s):  
Dark Matter ◽  
Hubble Constant ◽  
Big Bang ◽  
New Physics ◽  
Current Theory ◽  
Big Bang Theory ◽  
Celestial Bodies ◽  
Expansion Force ◽  
The Big Bang ◽  
The Universe

This article presents a new theory on redshift of light from celestial bodies. Lately it has been found that the Hubble constant calculated from different methods discord so much that calls arise for new physics to explain. Also, in addition to many unsolved puzzles like dark matter and source of expansion force, we shall show in this article that the current theory of redshift implies a few hidden, unreasonale assumptions. By assuming photon has temperature and its thermal energy is fully converted to wave energy, this article shows that photon can have a new redshift called Temperature Redshift, which not only is more significant for remote stars or galaxies, but also better fits the observational data, including those used in Hubble constant calculation. As such, if true, this new theory not only adds to our new understanding of photons, but may totally change our current understanding of the Universe, i.e., the Big Bang theory.

The Development of Physical Cosmology

2020 ◽  
pp. 3-226
Author(s):  
P. J. E. Peebles
Keyword(s):  
Particle Physics ◽  
Large Scale ◽  
Big Bang ◽  
Stellar Astronomy ◽  
Basic Physics ◽  
Substantial Progress ◽  
Physical Cosmology ◽  
The Big Bang ◽  
The Universe ◽  
Opening Up

This chapter introduces physical cosmology as the attempt to make sense of the large-scale nature of the material world by the methods of the natural sciences. It explains that physical cosmology operates under the special restrictions of astronomy, which is considered successful in sister fields, such as stellar astronomy and particle physics. It cites the substantial progress of cosmology as an enterprise in physical science, although the advances certainly have moved around considerable gaps in one's understanding. The chapter details how cosmology inherits from basic physics the more ancient and honorable tradition of attempts to understand where the world came from, where it is going, and why. It reviews believable evidence that the universe is expanding, the space between the galaxies opening up, and that this expansion traces back to a hot dense phase, the big bang.

The Alabama Insert

Think ◽  
2002 ◽  
Vol 1 (1) ◽  
pp. 7-20
Author(s):  
Richard Dawkins
Keyword(s):  
Public Schools ◽  
Life Forms ◽  
Big Bang ◽  
Human Beings ◽  
Text Book ◽  
Gallup Poll ◽  
The Bible ◽  
Age Of The Universe ◽  
The Big Bang ◽  
The Universe

Creationists believe that the Biblical account of the creation of the universe is literally true. God brought into existence the Earth and all its life forms in just six days. According to creationists, this event took place less than ten thousand years ago (they base their calculation of the age of the universe on the number of generations listed in the Bible).Creationists have succeeded in persuading large swathes of the general public that their theory is at least as scientifically respectable as the Big Bang/evolution alternative. A recent Gallup poll indicated that about 45% of US citizens currently believe that God created human beings ‘pretty much in [their] present form at one time or another within the last 10,000 years’.Two states, Arkansas and Louisiana, have even passed ‘balanced treatment’ laws requiring that creationism be taught alongside evolution in all state public schools. It was in Auburn, Alabama, shortly after that state required that a piece of paper be pasted into every biology school text book explaining why evolution is merely a ‘theory’ — and a highly questionable theory at that — that Richard Dawkins delivered the impromptu speech which forms the basis of the following.

scholarly journals Cosmology from quantum potential in a system of oscillating branes

2016 ◽  
Vol 31 (01) ◽  
pp. 1650004 ◽  
Author(s):  
Alireza Sepehri
Keyword(s):  
Generalized Uncertainty Principle ◽  
Scalar Fields ◽  
Big Bang ◽  
Fundamental String ◽  
Extra Energy ◽  
Age Of The Universe ◽  
The Big Bang ◽  
M Theory ◽  
Derivatives Of ◽  
The Universe

Recently, some authors proposed a new mechanism which gets rid of the Big Bang singularity and shows that the age of the universe is infinite. In this paper, we will confirm their results and predict that the universe may expand and contract many N fundamental strings decay to N M0–anti-M0-branes. Then, M0-branes join each other and build a M8-anti-M8 system. This system is unstable, broken and two anti-M4-branes, a compactified M4-brane, a M3-brane in addition to one M0-brane are produced. The M3-brane wraps around the compactified M4-brane and both of them oscillate between two anti-M4-branes. Our universe is located on the M3-brane and interacts with other branes by exchanging the M0-brane and some scalars in transverse directions. By wrapping of M3-brane, the contraction epoch of universe starts and some higher order of derivatives of scalar fields in the relevant action of branes are produced which are responsible for generating the generalized uncertainty principle (GUP). By oscillating the compactified M4-M3-brane and approaching one of anti-M4-branes, one end of M3-brane glues to the anti-M4-brane and other end remains sticking and wrapping around M4-brane. Then, by getting away of the M4-M3 system, M4 rolls, wrapped M3 opens and expansion epoch of universe begins. By closing the M4 to anti-M4, the mass of some scalars become negative and they make a transition to tachyonic phase. To remove these states, M4 rebounds, rolls and M3 wraps around it again. At this stage, expansion branch ends and universe enters a contraction epoch again. This process is repeated many times and universe expands and contracts due to oscillation of branes. We obtain the scale factor of universe in this system and find that its values only at t [Formula: see text] shrinks to zero. Thus, in our method, the Big Bang is replaced by the fundamental string and the age of universe is predicted to be infinite. Also, when tachyonic states disappear at the beginning of expansion branch, some extra energy is produced and leads to an increase in the velocity of opening of M3. In these conditions, our universe, which is located on this brane, expands very fast and experiences an inflation epoch. Finally, by reducing the fields in 11-dimensional M-theory to the fields in four-dimensional universe, we show that our theory matches with quantum field theory prescriptions.

scholarly journals Nuclear Constraints on the Age of the Universe

1983 ◽  
Vol 6 ◽  
pp. 241-253 ◽  
Author(s):  
David N. Schramm
Keyword(s):  
Cosmological Constant ◽  
Nuclear Physics ◽  
Big Bang ◽  
Distance Scale ◽  
The Other ◽  
Single Measurement ◽  
Age Of The Universe ◽  
The Big Bang ◽  
The Universe ◽  
Fair Degree

In this paper a review will be made of how one can use nuclear physics to put rather stringent limits on the age of the universe and thus the cosmic distance scale. As the other papers in this session have demonstrated there is some disagreement on the distance scale and thus the limits on the age of the universe (if the cosmological constant Λ = 0.) However, the disagreement is only over the last factor of 2, the basic timescale seems to really be remarkably well agreed upon. The universe is billions of years old - not thousands, not quintillions but billions of years. That our universe has a finite age is philosophically intriguing. That we can estimate that age to a fair degree of accuracy is truly impressive.No single measurement of the time since the Big Bang gives a specific, unambiguous age. Fortunately, we have at our disposal several methods that together fix the age with surprising precision.

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