A Time-DependentΛandGCosmological Model Consistent with Cosmological Constraints
In: Advances in Astronomy, Jg. 2016 (2016), S. 1-8
Online
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Zugriff:
The prevailing constantΛ-Gcosmological 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 parameterΛin 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 byΛis presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variableΛ-Gmodel. Cosmic constraints from action principles require that either bothGandΛremain time-invariant or both vary in time. Here, we propose a variableΛ-Gcosmological 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%.Λdecreases (Λ~τ-2, whereτis the normalized cosmic time) andGincreases (G~τn) with cosmic time. The model results depend only on the chosen value ofΛat present and in the far future and not directly onG.
Titel: |
A Time-DependentΛandGCosmological Model Consistent with Cosmological Constraints
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Autor/in / Beteiligte Person: | Kantha, Lakshmi |
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Zeitschrift: | Advances in Astronomy, Jg. 2016 (2016), S. 1-8 |
Veröffentlichung: | Hindawi Limited, 2016 |
Medientyp: | unknown |
ISSN: | 1687-7977 (print) ; 1687-7969 (print) |
DOI: | 10.1155/2016/9743970 |
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