Document Type

Article

Publication Date

2016

Publication Title

Advances in Astronomy

ISSN

1687-7977

Volume

2016

DOI

http://dx.doi.org/10.1155/2016/9743970

Abstract

The prevailing constant Lambda -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 Lambda 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 super(-52) m super(2) ). Moreover, the dark energy density represented by Lambda is presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variable Lambda -G model. Cosmic constraints from action principles require that either both G and Lambda remain time-invariant or both vary in time. Here, we propose a variable Lambda -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%. Lambda decreases ( Lambda ~ super( tau -2) , where tau is the normalized cosmic time) and G increases (G~ super( tau n) ) with cosmic time. The model results depend only on the chosen value of Lambda at present and in the far future and not directly on G.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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