ar X iv : a st ro - p h / 04 07 04 8 v 4 3 0 M ay 2 00 5 Future universe with w < − 1 Without Big Smash
نویسنده
چکیده
It is demonstrated that if cosmic dark energy behaves like a fluid with equation of state p = wρ (p and ρ being pressure and energy density respectively) as well as generalized Chaplygin gas simultaneously, Big Rip or Big Smash problem does not arise even for equation of state parameter w < −1. Unlike other phantom models, here, the scale factor for the future universe is found regular for all time. Experimental probes, during last few years suggest that the present universe is spatially flat as well as it is dominated by yet unknown form of dark energy [1,2]. Moreover, studies of Ia Supernova [3,4] and WMAP [5,6] show accelerated expansion of the present universe such thatä > 0 with a(t) being the scale factor of the Friedmann Robertson Walker line-element 1
منابع مشابه
ar X iv : a st ro - p h / 05 04 00 4 v 1 3 1 M ar 2 00 5 Large Scale Cosmological Inhomogeneities , Inflation And Acceleration Without Dark Energy
We describe the universe as a local, inhomogeneous spherical bubble embedded in a flat matter dominated FLRW universe. Generalized exact Friedmann equations describe the expansion of the universe and an early universe inflationary de Sitter solution is obtained. A non-perturbative expression for the deceleration parameter q is derived that can possibly describe the acceleration of the universe ...
متن کاملar X iv : a st ro - p h / 04 05 10 0 v 1 6 M ay 2 00 4 ( Two ) Open Questions in Stellar Nuclear Physics
No doubt, among the most exciting discoveries of the third millennium thus far are Oscillations of Massive Neutrinos and Dark Energy that leads to an accelerated expansion of the Universe. Accordingly, Nuclear Physics is presented with two extraordinary challenges: the need for precise (5% or better) prediction of solar neutrino fluxes within the Standard Solar Model, and the need for an accura...
متن کاملar X iv : a st ro - p h / 06 04 29 8 v 3 2 2 M ay 2 00 6 the Non - Gaussianity of Racetrack Inflation Models
In this paper, we use the result in [7] to calculate the non-Gaussianity of the racetrack models in [3, 5]. The two models give different nonGaussianities. Both of them are reasonable. PACS: 98.80.Cq, 98.80.Jk, 04.20.Gz
متن کاملar X iv : a st ro - p h / 04 05 27 3 v 1 1 4 M ay 2 00 4 Does Positronium Form in the Universe ?
Positronium (the bound state of electron and positron) has been thought to be formed after proton decay (> 10yr) through collisional recombination and then decays by pair annihilation, thereby changing the matter content of the universe. We revisit the issue of the formation of positronium in the long-term future of the universe in light of recent indication that the universe is dominated by da...
متن کاملar X iv : a st ro - p h / 04 04 37 1 v 2 1 5 M ay 2 00 4 In Quest of a True Model of the Universe 1
In order to explain the high-redshift supernovae Ia observations together with the recently made precise observations of the CMB anisotropy by WMAP, the standard big bang cosmology has to invoke some hypothetical matter with unnatural properties which is very speculative. This casts doubts upon the foundations of the standard cosmology and suggests that some theoretical concept may still be mis...
متن کامل