Determining Evolution of Cosmological Constant, Gravitational Constant and Speed of Light Using Nonadiabatic Cosmological Model and LLR Findings

Gupta Gupta

doi:10.3390/galaxies7030067

Abstract

We have shown that the Hubble constant H0 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 the time evolution of G/c2 (≡K) and dark energy density εΛ related to Λ by explicitly incorporating the nonadiabatic nature of the universe in the Friedmann equation. We have found (dK/dt)/K = 1.8H0 and, for redshift z, εΛ,z/εΛ,0 = 0.4+0.61+z-1.52. Since the two expressions are related, we believe that the time variation of K (and therefore that of G and c) is manifested as dark energy in cosmological models. When we include the null finding of the lunar laser ranging (LLR) for (dG/dt)/G and relax the constraint that c is constant in LLR measurements, we get (dG/dt)/G = 5.4H0 and (dc/dt)/c = 1.8H0. Further, when we adapt the standard ΛCDM model for the z dependency of εΛ rather than it being a constant, we obtain surprisingly good results fitting the SNe Ia redshift z vs distance modulus µ data. An even more significant finding is that the new ΛCDM model, when parameterized with low redshift data set (z < 0.5), yields a significantly better fit to the data sets at high redshifts (z > 0.5) than the standard ΛCDM model. Thus, the new model may be considered robust and reliable enough for predicting distances of radiation emitting extragalactic redshift sources for which luminosity distance measurement may be difficult, unreliable, or no longer possible.

Highlights

The standard ΛCDM model has been seen as the most successful model for explaining cosmology, including the extragalactic redshift, cosmic microwave background, nucleosynthesis in the early universe, inflation in the very early universe, structure formation, and the rotational velocity of galaxies, etc
The question naturally arises: are the dark energy and dark matter real or manifestations of some phenomena of nature that we are trying to capture in the standard model? The most controversial has been the cosmological constant Λ that was introduced unhappily by Einstein in his field equations to prevent the universe from
The data used in this work is the so-called Pantheon sample of 1048 supernovae 1a developed by Scolnic and his associates [25] in the rage of 0.01 < z < 2.3

Summary

Introduction

The standard ΛCDM model has been seen as the most successful model for explaining cosmology, including the extragalactic redshift, cosmic microwave background, nucleosynthesis in the early universe, inflation in the very early universe, structure formation, and the rotational velocity of galaxies, etc. Most cosmologists tend to explain observed phenomena using the standard model. Dark energy and dark matter in ΛCDM models remain controversial and unobservable in spite of major efforts spanning many decades. The question naturally arises: are the dark energy and dark matter real or manifestations of some phenomena of nature that we are trying to capture in the standard model? The most controversial has been the cosmological constant Λ that was introduced unhappily by Einstein in his field equations to prevent the universe from The question naturally arises: are the dark energy and dark matter real or manifestations of some phenomena of nature that we are trying to capture in the standard model? The most controversial has been the cosmological constant Λ that was introduced unhappily by Einstein in his field equations to prevent the universe from

Results

Discussion

Conclusion