scholarly journals A New Approach: About the Appearance of “Dark Matter” Effects in the Process of Expansion of the Universe*

2021 ◽  
Vol 12 (07) ◽  
pp. 1040-1047
Author(s):  
Leonid Sitnikov
Keyword(s):  
Dark Matter ◽  
New Approach ◽  
Matter Effects ◽  
Expansion Of The Universe ◽  
The Universe

scholarly journals Elementary Particles, Dark Matter, and Dark Energy: Descriptions that Explain Aspects of Dark Matter to Ordinary Matter Ratios, Inflation, Early Galaxies, and Expansion of the Universe

2020 ◽  
Author(s):  
Thomas Buckholtz
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Conservation Laws ◽  
Galaxy Formation ◽  
Elementary Particles ◽  
Ordinary Matter ◽  
Matter Effects ◽  
Expansion Of The Universe ◽  
Early Galaxies ◽  
The Universe

Physics theory has yet to settle on specific descriptions for new elementary particles, for dark matter, and for dark energy forces. Our work extrapolates from the known elementary particles. The work suggests well-specified candidate descriptions for new elementary particles, dark matter, and dark energy forces. This part of the work does not depend on theories of motion. This work embraces symmetries that correlate with motion-centric conservation laws. The candidate descriptions seem to explain data that prior physics theory seems not to explain. Some of that data pertains to elementary particles. Our theory suggests relationships between masses of elementary particles. Our theory suggests a relationship between the strengths of electromagnetism and gravity. Some of that data pertains to astrophysics. Our theory seems to explain ratios of dark matter effects to ordinary matter effects. Our theory seems to explain aspects of galaxy formation. Some of that data pertains to cosmology. Our theory suggests bases for inflation and for changes in the rate of expansion of the universe. Generally, our work proposes extensions to theory in three fields. The fields are elementary particles, astrophysics, and cosmology. Our work suggests new elementary particles and seems to explain otherwise unexplained data.

scholarly journals Dark Matter in the Universe

1986 ◽  
Vol 7 ◽  
pp. 27-38 ◽  
Author(s):  
Vera C. Rubin
Keyword(s):  
Dark Matter ◽  
Deceleration Parameter ◽  
Big Bang ◽  
Theoretical Cosmology ◽  
Observational Cosmology ◽  
The Past ◽  
The Galaxy ◽  
Expansion Of The Universe ◽  
The Big Bang ◽  
The Universe

Thirty years ago, observational cosmology consisted of the search for two numbers: Ho, the rate of expansion of the universe at the position of the Galaxy; and qo, the deceleration parameter. Twenty years ago, the discovery of the relic radiation from the Big Bang produced another number, 3oK. But it is the past decade which has seen the enormous development in both observational and theoretical cosmology. The universe is known to be immeasurably richer and more varied than we had thought. There is growing acceptance of a universe in which most of the matter is not luminous. Nature has played a trick on astronomers, for we thought we were studying the universe. We now know that we were studying only the small fraction of it that is luminous. I suspect that this talk this evening is the first IAU Discourse devoted to something that astronomers cannot see at any wavelength: Dark Matter in the Universe.

The accelerating universe and dark energy

2014 ◽  
Vol 23 (06) ◽  
pp. 1430012 ◽  
Author(s):  
Charles Baltay
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Parameters ◽  
Accelerating Universe ◽  
Heavy Particles ◽  
Familiar World ◽  
Acceleration Of The Universe ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Present Understanding

The recent discovery by Riess et al.1 and Perlmutter et al.2 that the expansion of the universe is accelerating is one of the most significant discoveries in cosmology in the last few decades. To explain this acceleration a mysterious new component of the universe, dark energy, was hypothesized. Using general relativity (GR), the measured rate of acceleration translates to the present understanding that the baryonic matter, of which the familiar world is made of, is a mere 4% of the total mass-energy of the universe, with nonbaryonic dark matter making up 24% and dark energy making up the majority 72%. Dark matter, by definition, has attractive gravity, and even though we presently do not know what it is, it could be made of the next heavy particles discovered by particle physicists. Dark energy, however, is much more mysterious, in that even though we do not know what it is, it must have some kind of repulsive gravity and negative pressure, very unusual properties that are not part of the present understanding of physics. Investigating the nature of dark energy is therefore one of the most important areas of cosmology. In this review, the cosmology of an expanding universe, based on GR, is discussed. The methods of studying the acceleration of the universe, and the nature of dark energy, are presented. A large amount of experimentation on this topic has taken place in the decade since the discovery of the acceleration. These are discussed and the present state of knowledge of the cosmological parameters is summarized in Table 7 below. A vigorous program to further these studies is under way. These are presented and the expected results are summarized in Table 10 below. The hope is that at the end of this program, it would be possible to tell whether dark energy is due to Einstein's cosmological constant or is some other new constituent of the universe, or alternately the apparent acceleration is due to some modification of GR.

scholarly journals DO RECENT SUPERNOVAE Ia OBSERVATIONS TEND TO RULE OUT ALL THE COSMOLOGIES?

2007 ◽  
Vol 16 (10) ◽  
pp. 1641-1651 ◽  
Author(s):  
RAM GOPAL VISHWAKARMA
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Lensing ◽  
Weakly Interacting Massive Particles ◽  
Cosmological Models ◽  
Accelerated Expansion ◽  
Standard Candle ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Rule Out

Dark energy and the accelerated expansion of the universe have been the direct predictions of the distant supernovae Ia observations which are also supported, indirectly, by the observations of the CMB anisotropies, gravitational lensing and the studies of galaxy clusters. Today these results are accommodated in what has become the concordance cosmology: a universe with flat spatial sections t = constant with about 70% of its energy in the form of Einstein's cosmological constant Λ and about 25% in the form of dark matter (made of perhaps weakly-interacting massive particles). Though the composition is weird, the theory has shown remarkable successes at many fronts. However, we find that as more and more supernovae Ia are observed, more accurately and towards higher redshift, the probability that the data are well-explained by the cosmological models decreases alarmingly, finally ruling out the concordance model at more than 95% confidence level. This raises doubts against the "standard candle"-hypothesis of the supernovae Ia and their use in constraining the cosmological models. We need a better understanding of the entire SN Ia phenomenon in order to extract cosmological consequences from them.

scholarly journals Unified Description of Dark Energy and Dark Matter within the Generalized Hybrid Metric-Palatini Theory of Gravity

Universe ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 78 ◽  
Author(s):  
Paulo M. Sá
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Fields ◽  
Accelerated Expansion ◽  
Late Time ◽  
Intermediate Phases ◽  
Expansion Of The Universe ◽  
Theory Of Gravity ◽  
The Universe ◽  
Unified Description

The generalized hybrid metric-Palatini theory of gravity admits a scalar-tensor representation in terms of two interacting scalar fields. We show that, upon an appropriate choice of the interaction potential, one of the scalar fields behaves like dark energy, inducing a late-time accelerated expansion of the universe, while the other scalar field behaves like pressureless dark matter that, together with ordinary baryonic matter, dominates the intermediate phases of cosmic evolution. This unified description of dark energy and dark matter gives rise to viable cosmological solutions, which reproduce the main features of the evolution of the universe.

scholarly journals Accelerated expansion of the Universe in the presence of dark matter pressure

2020 ◽  
Vol 98 (2) ◽  
pp. 210-216
Author(s):  
Zeinab Rezaei
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Hubble Parameter ◽  
Energy Equation ◽  
Accelerated Expansion ◽  
Luminosity Distance ◽  
Modern Cosmology ◽  
History Of ◽  
Expansion Of The Universe ◽  
The Universe

Expansion dynamics of the Universe is an important subject in modern cosmology. The dark energy equation of state determines these dynamics so that the Universe is in an accelerating phase. However, dark matter (DM) can also affect the accelerated expansion of the Universe through its equation of state. In the present work, we explore the expansion dynamics of the Universe in the presence of DM pressure. In this regard, applying the DM equation of state from the observational data related to the rotational curves of galaxies, we calculate the evolution of DM density. Moreover, the Hubble parameter, history of scale factor, luminosity distance, and deceleration parameter are studied while the DM pressure is taken into account. Our results verify that the DM pressure leads to higher values of the Hubble parameter at each redshift and the expansion of the Universe grows due to the DM pressure.

scholarly journals Creation of mass dimension one fermionic particles in asymptotically expanding universe

2017 ◽  
Vol 26 (12) ◽  
pp. 1730028 ◽  
Author(s):  
S. H. Pereira ◽  
Rodrigo C. Lima
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Particle Creation ◽  
Analytic Solutions ◽  
Coupling Case ◽  
Mass Dimension ◽  
Fermionic Fields ◽  
Expansion Of The Universe ◽  
Dimension One ◽  
The Universe

In the present work we study the process of particle creation for mass dimension one fermionic fields (sometimes named Elko) as a consequence of expansion of the universe. We study the effect driven by an expanding background that is asymptotically Minkowski in the past and future. The differential equation that governs the time mode function is obtained for the conformal coupling case and, although its solution is nonanalytic, within an approximation that preserves the characteristics of the terms that break analyticity, analytic solutions are obtained. Thus, by means of Bogolyubov transformations technique, the number density of particles created is obtained, which can be compared to exact solutions already present in literature for scalar and Dirac particles. The spectrum of the created particles was obtained and it was found that it is a generalization of the scalar field case, which converges to the scalar field one when the specific terms concerning the Elko field are dropped out. We also found that lighter Elko particles are created in larger quantities than the Dirac fermionic particles. By considering the Elko particles as candidate to the dark matter in the universe, such result shows that there are more light dark matter (Elko) particles created by the gravitational effects in the universe than baryonic (fermionic) matter, in agreement to the standard model.

scholarly journals Modeling that predicts elementary particles and explains data about dark matter, early galaxies, and the cosmos

2020 ◽  
Author(s):  
Thomas Buckholtz
Keyword(s):  
Dark Matter ◽  
Harmonic Oscillator ◽  
Galaxy Formation ◽  
Elementary Particles ◽  
Ordinary Matter ◽  
Expansion Of The Universe ◽  
Early Galaxies ◽  
The Masses ◽  
The Universe ◽  
New Particles

We try to solve three decades-old physics challenges. List all elementary particles. Describe dark matter. Describe mechanisms that govern the rate of expansion of the universe. We propose new modeling. The modeling uses extensions to harmonic oscillator mathematics. The modeling points to all known elementary particles. The modeling suggests new particles. Based on those results, we do the following. We explain observed ratios of dark matter amounts to ordinary matter amounts. We suggest details about galaxy formation. We suggest details about inflation. We suggest aspects regarding changes in the rate of expansion of the universe. We interrelate the masses of some elementary particles. We interrelate the strengths of electromagnetism and gravity. Our work seems to offer new insight regarding applications of harmonic oscillator mathematics. Our work seems to offer new insight regarding three branches of physics. The branches are elementary particles, astrophysics, and cosmology.

scholarly journals A Physico-Chemical Approach To Understanding Cosmic Evolution: Thermodynamics  Of Expansion And Composition Of The Universe

2021 ◽  
Author(s):  
Carlos A. Melendres
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
State Parameter ◽  
Big Bang ◽  
Fundamental Particles ◽  
Physico Chemical ◽  
Expansion Of The Universe ◽  
Cooling Phase ◽  
The Big Bang ◽  
The Universe

Abstract We present a physico-chemical approach towards understanding the mysteries associated with the Inflationary Big Bang model of Cosmic evolution based on a theory that space consists of energy quanta. We use thermodynamics to elucidate the expansion of the universe, its composition, and the nature of dark energy and dark matter. The universe started from an atomic size volume of space quanta at very high temperature. Upon expansion and cooling, phase transitions resulted in the formation of fundamental particles, and matter which grow into stars, galaxies, and clusters due to gravity. From cooling data on the universe, we constructed a thermodynamic phase diagram of composition of the universe, from which we obtained a correlation between dark energy and the energy of space. Using Friedmann’s equations, our Quantum Space model fitted well the WMAP data on cosmic composition with an equation of state parameter, w= -0.7. The expansion of the universe was adiabatic and decelerating during the first 7 billion years after the Big Bang. It accelerated due to the dominance of dark energy at 7.25 x 109 years, in good agreement with BOSS measurements. Dark Matter is identified as a plasma form of matter similar to that which existed before recombination and during reionization.

scholarly journals A Brief Review on Primordial Black Holes as Dark Matter

2021 ◽  
Vol 8 ◽  
Author(s):  
Pablo Villanueva-Domingo ◽  
Olga Mena ◽  
Sergio Palomares-Ruiz
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Primordial Black Holes ◽  
Evolution Of The Universe ◽  
Matter Effects ◽  
The Universe ◽  
Hawking Evaporation

Primordial black holes (PBHs) represent a natural candidate for one of the components of the dark matter (DM) in the Universe. In this review, we shall discuss the basics of their formation, abundance and signatures. Some of their characteristic signals are examined, such as the emission of particles due to Hawking evaporation and the accretion of the surrounding matter, effects which could leave an impact in the evolution of the Universe and the formation of structures. The most relevant probes capable of constraining their masses and population are discussed.

Sign in / Sign up

Export Citation Format

Share Document