A Time-Dependent [Lambda] and G Cosmological Model Consistent with Cosmological Constraints

• Published in: Advances in astronomy 2016-01, Vol.2016
• Main Author: Kantha, L
• Format: Article
• Language: English
• Subjects: Cosmology; Dark energy; Dimensional analysis; Entropy; Star & galaxy formation; Stars & galaxies
• ISSN: 1687-7969; 1687-7977
• DOI: 10.1155/2016/9743970

The prevailing constant Λ-G cosmological model agrees with observational evidence including the observed red shift, Big Bang Nucleosynthesis (BBN), and the current rate of acceleration. It assumes that matter contributes 27% to the current density of the universe, with the rest (73%) coming from dark energy represented by the Einstein cosmological parameter Λ in the governing Friedmann-Robertson-Walker equations, derived from Einstein's equations of general relativity. However, the principal problem is the extremely small value of the cosmological parameter (~10-52 m2). Moreover, the dark energy density represented by Λ is presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variable Λ-G model. Cosmic constraints from action principles require that either both G and Λ remain time-invariant or both vary in time. Here, we propose a variable Λ-G cosmological model consistent with the latest red shift data, the current acceleration rate, and BBN, provided the split between matter and dark energy is 18% and 82%. Λ decreases (Λ~[superscript]τ-2[/superscript] , where τ is the normalized cosmic time) and G increases (G~[superscript]τn[/superscript] ) with cosmic time. The model results depend only on the chosen value of Λ at present and in the far future and not directly on G.