Gravitational wave (GW) astronomy provides an independent way to estimate cosmological parameters. The detection of GWs from a coalescing binary allows a direct measurement of its luminosity distance, so these sources are referred to as “standa...
The standard models of particle physics and of cosmology have been enormously successful in correlating a large amount of data. However, there are missing pieces and we are still far from what the ultimate model may look like. We give a broad perspec...
Currently, there is no widely accepted consensus regarding a consistent thermodynamic framework within the special relativity paradigm. However, by postulating that the inverse temperature 4-vector, denoted as β, is future-directed and time-like...
If the recent acceleration phase of the expanding Universe is driven by a cosmologicalconstant the Universe is future-eternal with a few far reaching ramifications and disturbing consequences. We demonstrate with a non-ΛCDM cosmological model,...
The luminosity distance in the standard cosmology as given by ΛCDM and, consequently, the distance modulus for supernovae can be defined by the Padé approximant. A comparison with a known analytical solution shows that the Padé approximant for the lu...
The standard ΛCDM model is reasonably successful in describing the universe, and is the most widely acceptable model in cosmology. However, there are several theoretical issues, such as the initial singularity, the cosmological constant problem, the...
Many models have been proposed to explain the intergalactic redshift using different observational data and different criteria for the goodness-of-fit of a model to the data. The purpose of this paper is to examine several suggested models using the...
Relaxing the temporal constancy constraint on coupling constants in an expanding universe results in Friedmann equations containing terms that may be interpreted as dark energy and dark matter. When tired light (TL) was considered to complement the r...
Modern cosmology continues to struggle with unresolved questions concerning the origins of dark matter and dark energy. To explore these challenges, this study presents the Source Energy Field Theory (SEFT)—a new theoretical framework that offe...
By relaxing the constraint of adiabatic universe used in most cosmological models, we have shown that the new approach provides a better fit to the supernovae Ia redshift data with a single parameter, the Hubble constant H0, than the standard &Lambda...
The standard ΛCDM model, despite its agreement with observational data, still has some issues unaddressed, such as the problem of initial singularity. Solving that problem usually requires modifications of general relativity. However, there ap...
The postulate of universal local Weyl scaling (conformal) symmetry modifies both general relativity and the Higgs scalar field model. The conformal Higgs model (CHM) acquires a cosmological effect that fits the observed accelerating Hubble expansion...
We have used the varying physical constant approach to resolve the flatness problem in cosmology. Friedmann equations are modified to include the variability of speed of light, gravitational constant, cosmological constant, and the curvature constant...
The Hubble diagram (HD) is a plot that contains a luminous distance modulus presented with respect to the redshift. The distance modulus–redshift relation of the most well-known “standard candles”, the type Ia supernovae (SN), is a...
A wide range of large scale observations hint towards possible modifications on the standard cosmological model which is based on a homogeneous and isotropic universe with a small cosmological constant and matter. These observations, also known as “c...
The Hubble tension, a persistent discrepancy between early and late Universe measurements of H0, poses a significant challenge to the standard cosmological model. In this work, we present a new Bayesian hierarchical framework designed to meticulously...
Our Modified Gravity Theory (MOG) is a gravitational theory without exotic dark matter, based on an action principle. MOG has been used successfully tomodel astrophysical phenomena, such as galaxy rotation curves, galaxy cluster masses and lensing. M...
We investigate f (R, T) gravity, where R is the Ricci scalar and T the trace of the energy–momentum tensor, focusing on the subclass defined by f (R, T) = R + 2f (T). Instead of assuming a parametric...
We have developed a cosmological model by allowing the speed of light c, gravitational constant G and cosmological constant Λ in the Einstein filed equation to vary in time, and solved them for Robertson-Walker metric. Assuming the universe is...
We have shown that the Hubble constant H 0 embodies the information about the evolutionary nature of the cosmological constant Λ , gravitational constant G , and the speed of light c . We have derived expressions for t...