Locally Varying Hubble Parameter in Terms of Reduced Friedmann Equation

Assessment of the Hubble parameter as an indicator of the expansion rate of the universe holds a central position in the field of astronomy. From its initial estimate of about 500 km⋅sec-1⋅parsc-1, this value had been steadily amended as the observational tools became more accurate and precise. Despite this, a gap remains between the value of observations relating to local and nonlocal estimations of the Hubble parameter that gave rise to what became known as the Hubble tension. This tension is addressed here while dealing with space fabric as a cosmological fluid that undergoes transition.

A Comment on the Hubble Expansion Parameter Tension

We point out that the recent baryon acoustic oscillation measurement by the Dark Energy Survey collaboration relieves the Hubble expansion parameter tension.

How to Predict the Temperature of the CMB Directly Using the Hubble Parameter and the Planck Scale Using the Stefan-Boltzmann Law

Based on recent progress in quantum gravity and quantum cosmology, we are also presenting a way to estimate the temperature in the cosmos, the Hubble sphere, from a relation between the Planck temperature and the Hubble scale. Our analysis predicts the Hubble sphere temperature of 2.72 K with the one standard deviation confidence interval between 2.65 K and 2.80 K, which corresponds well with the measured temperature observed from the cosmic microwave background (CMB) of about 2.72 K. This adds evidence that there is a close connection between the Planck scale, gravity, and the cosmological scales as anticipated by Eddington already in 1918.1.

Prospect for Cosmological Parameter Estimation Using Future Hubble Parameter Measurements

We constrain cosmological parameters using only Hubble parameter data and quantify the impact of future Hubble parameter measurements on parameter estimation for the most typical dark energy models. We first constrain cosmological parameters using 52 current Hubble parameter data including the Hubble constant measurement from the Hubble Space Telescope. Then we simulate the baryon acoustic oscillation signals from WFIRST(Wide-Field Infrared Survey Telescope) covering the redshift range of z ∈ [0.5, 2] and the redshift drift data from E-ELT(European Extremely Large Telescope) in the redshift range of z ∈ [2, 5]. It is shown that solely using the current Hubble parameter data could give fairly good constraints on cosmological parameters. Compared to the current Hubble parameter data, with the WFIRST observation the H(z) constraints on dark energy would be improved slightly, while with the E-ELT observation the H(z) constraints on dark energy is enormously improved.

Using Pantheon and Hubble parameter data to constrain the Ricci dark energy in a Bianchi Ⅰ Universe

In this work,we use the most recent publicly available type Ⅰa supernova(SNIa) compilations and H(z) data.A well formulated cosmological model based on Bianchi type Ⅰ(BI) metric is implemented in the presence of the Ricci dark energy model.Using the maximum likelihood technique,we estimate the present value of Hubble's constant H_(0)=70.339±0.743,matter density parameter Ω_(m_(0))=0.297±0.031,anisotropy parameter Ω_(σ_(0))=-0.004 01 ± 0.001 07 within 1σ′ confidence level by bounding our derived model with recent joint Pantheon and H(z)data.We have constrained the present value of the equation of state parameter as ω_(de)=-1.17 joint with the observational data.The present value of the deceleration parameter of the Universe in the derived model is obtained as q_(0)=-0.749_(-0.086)^(+0.076).Transition redshift is also derived as z_(tr)~0.551 with the recent observations(Pantheon+H(z)) datasets.Finally,we compare the anisotropy effects on the evolution of H(z) for the proposed model under consideration with different observational datasets.

From the Hubble Constant to the Black Hole Model. Universe Expansion with Matter Creation and a New Perspective on Dark Energy Observations

Comparison of the Hubble parameter with cosmological quantities strongly supports the black hole model for the description of the Universe evolution. Such evolution requires matter creation and has implications for what is currently referred to as “dark energy” and the “cosmological constant”.

A New Version of the Lambda-CDM Cosmological Model, with Extensions and New Calculations

This article gives a state-of-the-art description of the cosmological Lambda-CDM model and in addition, presents extensions of the model with new calculations of background and CMB functions. Chapters 1-4 describe the background part of the model, i.e. the evolution of scale factor and density according to the Friedmann equations, and its extension, which results in a correction of the Hubble parameter, in agreement with new measurements (Cepheids-SNIa and Red-Giants). Based on this improved background calculation presented in chapters 5-9 the perturbation part of the model, i.e. the evolution of perturbation and structure according to the perturbed Einstein equations and continuity-Euler equations, and the power spectrum of the cosmic microwave background (CMB) is calculated with a new own code.

New Conservation Law and a Consideration as to When Forming a Cosmological Constant Term: Using Fifth Force for Frequency of BEC “Gravitons” and Cosmological Constant Formed before BEC Gravitons Form

We use scalar fields. The scalar field version which we are using is one from Padmanabhan, and the problem is that the scalar field in the Padmanabhan representation is initially only dependent on time. We also refer to a new assumed conservation law which will give new structure as to inflationary expansion and its immediate aftermath. That of the Hubble “constant” is divided by the “time derivative” of the scalar field in the inflation regime and then a long time afterwards. In doing so, we help define when the cosmological constant may form and what they says about the advent of dark energy.

Probability of Obtaining the Planck Constant, in a Universe Modeled as a Giant Black Hole by Bose Einstein Condensates of Gravitons Using Hawking Argument and Scaling

We use the methodology of A. D. Linde to model the probability of obtaining a cosmological constant which is in turn affected by scaling arguments for a Bose Einstein gravitational condensate as given by Chavanis, in 2015. The net result, is that the scaling argument so provided allows for a gravitational constant commensurate with the size of the Universe, using arguments which appear to be simple but which give, if one has the conditions for modeling the Universe as a “black hole” virtually 100 % chance for the cosmological constant arising.

Using Model of a Universe as Similar to a Black Hole, Ask If We Have to Have Singularities, If We Are Looking at Initial Time Step and Entropy, from the Beginning

Based on the idea of cyclic conformal cosmology, we formulate entropy and quantum number n, and then utilize the minimum uncertainty principle, where Delta E times Delta t equals h-bar, to actualize a prototype delta t time stop in the breakup of supermassive black holes into countless Planck mass-sized black holes. This helps to link entropy, time step, and primordial conditions and define when the cosmological constant may form and the initial inflationary expansion “speed”. All this is used to obtain a model of if a singularity, initially is needed.

How Flat Space Cosmology Models Dark Energy

Equations of Flat Space Cosmology (FSC) are utilized to characterize the model’s scalar temporal behavior of dark energy. A table relating cosmic age, cosmological redshift, and the temporal FSC Hubble parameter value is created. The resulting graph of the log of the Hubble parameter as a function of cosmological (or galactic) redshift has a particularly interesting sinuous shape. This graph greatly resembles what ΛCDM proponents have been expecting for a scalar temporal behavior of dark energy. And yet, the FSC Rh = ct model expansion, by definition, neither decelerates nor accelerates. It may well be that apparent early cosmic deceleration and late cosmic acceleration both ultimately prove to be illusions produced by a constant-velocity, linearly-expanding, FSC universe. Furthermore, as discussed herein, the FSC model would appear to strongly support Freedman et al. in the current Hubble tension debate, if approximately 14 Gyrs can be assumed to be the current cosmic age.

Free Electrons Compton Scattering Can Produce an Illusion of Expanding Universe

The high-precision measurements of the Hubble parameter make the theory of cosmic expansion more and more confusing, which bolsters the idea that new physics may be needed to explain the mismatch. Astronomical observations show that the Universe is expanding exponentially. Free electron Compton scattering (FEC) can produce the illusion of exponentially expanding Universe: FEC causes photons to redshift exponentially, and the photon beam exponentially expands along the propagation direction. Is this a coincidence? The redshift factor of the FEC is z = (1+z);the beam length stretch factor (time dilation of the supernova curve) of the FEC is z = (1+z);the expansion factor of the beam volume of the FEC is z = (1+z)3, and the FEC effect does not blur the image of distant galaxies. The reason for rejecting the “tired light” does not hold in FEC.

Antigravity—Its Manifestations and Origin

Dark energy has been introduced in order to explain the observed acceleration of the expansion of our Universe. It seems to be distributed almost uniformly and it has an essential influence on the present value of the Hubble constant which characterizes the rate of this expansion. The Newtonian theory of gravitation is formulated so that the laws of conservation of energy and momentum hold. However, the Universe is designed so that the total amount of energy is slowly, but continually increasing, since its expansion is accelerating. Our examples show that even the Solar System and also our Galaxy imperceptibly expand thanks to dark energy whose origins are tiny antigravity forces. We claim that these forces appear due to the finite speed of gravitational interaction, which causes gravitational aberration effects. We show that effects of dark energy are observable;they are not only globally, but also in local systems. These effects can be measured and are comparable with the present value of the Hubble constant.

Predicting Dark Energy Survey Results Using the Flat Space Cosmology Model

The Flat Space Cosmology (FSC) model is utilized to show how this model predicts the value of the Hubble parameter at each epoch of cosmic expansion. Specific attention in this paper is given to correlating the observable galactic redshifts since the beginning of the “cosmic dawn” reionization epoch. A graph of the log of the Hubble parameter as a function of redshift z is presented as the FSC prediction of the pending Dark Energy Survey results. In the process, it is discovered that the obvious tension between the SHOES local Hubble constant value and the 2018 Planck Survey and the 2018 Dark Energy Survey global Hubble constant values may be explained by a time-variable, scalar, Hubble parameter acting in accordance with the FSC model.

Phantom cosmologies from the simplest parameterization of the DE model using observational data in a BI type universe

To scrutinize the nature of dark energy,many equations of state have been proposed.In this context,we examine the simplest parameterization of the equation of state parameter of dark energy in an anisotropic Bianchi type I universe compared with theΛCDM model.Using different combinations of data samples,including Pantheon and Pantheon+H(z),alongside applying the minimization of theχ^(2)function of the distance modulus of data samples,we obtain the constrained values of cosmographic parameters in the parameterization of the dark energy scenario.One condition of the phantom barrier crossing is acquired.Several physical properties of the universe are discussed by considering the anisotropy effect and different observational data points.One should note that the deductions of the cosmological parameter verify recent observational data.

Hypersphere World-Universe Model

Dirac’s themes were the unity and beauty of Nature. He identified three revolutions in modern physics: Relativity, Quantum Mechanics and Cosmology. In his opinion: “The new cosmology will probably turn out to be philosophically even more revolutionary than relativity or the quantum theory, perhaps looking forward to the current bonanza in cosmology, where precise observations on some of the most distant objects in the universe are shedding light on the nature of reality, on the nature of matter and on the most advanced quantum theories” [Farmelo, G. (2009) The Strangest Man. The Hidden Life of Paul Dirac, Mystic of the Atom. Basic Books, Britain, 661 p]. In 1937, Paul Dirac proposed the Large Number Hypothesis and the Hypothesis of the variable gravitational “constant”;and later added the notion of continuous creation of Matter in the World. The developed Hypersphere World-Universe Model (WUM) follows these ideas, albeit introducing a different mechanism of matter creation. In this paper, we show that WUM is a natural continuation of Classical Physics and it can already serve as a basis for a New Cosmology proposed by Paul Dirac.

Hypersphere World-Universe Model: Evolution of the World

The main objective of this paper is to discuss the Evolution of a 3D Finite World (that is a Hypersphere of a 4D Nucleus of the World) from the Beginning up to the present Epoch in frames of World-Universe Model (WUM). WUM is the only cosmological model in existence that is consistent with the Law of Conservation of Angular Momentum. To be consistent with this Fundamental Law, WUM introduces Dark Epoch (spanning from the Beginning of the World for 0.45 billion years) when only Dark Matter (DM) Macroobjects (MOs) existed, and Luminous Epoch (ever since for 13.77 billion years) when Luminous MOs emerged due to Rotational Fission of Overspinning DM Superclusters’ Cores and self-annihilation of Dark Matter Particles (DMPs). WUM envisions that DM is created by the Universe in the 4D Nucleus of the World. Dark Matter Particles (DMPs) carry new DM into the 3D Hypersphere World. Luminous Matter is a byproduct of DMPs self-annihilation. By analogy with 3D ball, which has two-dimensional sphere surface (that has surface energy), we can imagine that the 3D Hypersphere World has a “Surface Energy” of the 4D Nucleus. WUM solves a number of physical problems in contemporary Cosmology and Astrophysics through DMPs and their interactions: Angular Momentum problem in birth and subsequent evolution of Galaxies and Extrasolar systems—how do they obtain it;Fermi Bubbles—two large structures in gamma-rays and X-rays above and below Galactic center;Missing Baryon problem related to the fact that the observed amount of baryonic matter did not match theoretical predictions. WUM reveals Inter-Connectivity of Primary Cosmological Parameters and calculates their values, which are in good agreement with the latest results of their measurements. In 2013, WUM predicted the values of the following Cosmological parameters: gravitational, concentration of intergalactic plasma, and the minimum energy of photons, which were experimentally confirmed in 2015-2018. “The Discovery of a Supermassive Compact Object at the Centre of Our Galaxy” (Nobel Prize in Physics 2020) made by Prof. R. Genzel and A. Ghez is a confirmation of one of the most important predictions of WUM in 2013: “Macroobjects of the World have cores made up of the discussed DM particles. Other particles, including DM and baryonic matter, form shells surrounding the cores”.

Anisotropic Bianchi Type-I Magnetized String Cosmological Models with Decaying Vacuum Energy Density A(t)

The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as formulated by Letelier （1983）, has been used to construct massive string cosmological models for which we assume the expansion scalar in the models is proportional to one of the components of shear tensor. The Einstein＇s field equations have been solved by applying a variation law for generalized Hubble＇s parameter in Bianchi-I space-time. The variation law for Hubble＇s parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein＇s field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. We have made a comparative study of accelerating and decelerating models in the presence of string scenario. The study reveals that massive strings dominate in the decelerating universe whereas strings dominate in the accelerating universe. The strings eventually disappear from the universe for sufficiently large times, which is in agreement with current astronomical observations. The cosmological constant A is found to be a positive decreasing function of time which is corroborated by results from recent supernovae Ia observations. The physical and geometric properties of the models have been also discussed in detail.

From the Beginning of the World to the Beginning of Life on Earth

Hypersphere World-Universe Model (WUM) is, in fact, a Paradigm Shift in Cosmology [1]. In this paper, we provide seven Pillars of WUM: Medium of the World;Inter-Connectivity of Primary Cosmological Parameters;Creation of Matter;Multicomponent Dark Matter;Macroobjects;Volcanic Rotational Fission;Dark Matter Reactors. We describe the evolution of the World from the Beginning up to the birth of the Solar System and discuss the condition of the Early Earth before the beginning of life on it.

How Initial Degrees of Freedom May Contribute to Initial Effective Mass, i.e. Effective Mass of the Universe Proportional to (D.O.F.) to the 1/4th Power by an Enormous Initial Degree of Freedom Value

Using a relationship between Hubble’s “parameter”, Temperature, Energy and effective mass, from there obtain in 3 + 1 dimensions a relationship between effective mass, and the initial degrees of freedom, to the 1/4th power, we will discuss candidates for entry into this, assuming for a start that initial universe conditions are similar to a black hole, i.e. a nearly singular start to inflationary expansion;this would necessitate a HUGE initial degree of freedom value as outlined in our argument.