New cosmology - dark energy unnecessary

[Chronos]

v4 is a definite improvement in my mind [which is not necessarily a good sign]. Some of my issues with the initial release have been placated. I still have difficulty grasping the consequence of super horizon fluctuations within our Hubble bubble. I am stuck on the notion this is like trying to view IR wavelengths through a UV filter. I wonder though, is the intent to suggest that accelerated expansion is an illusion created by interference fringes in the super horizon fluctuations? The assertion our observable bubble was causally connected to the bulk universe prior to inflation is also troubling. I can't shake the feeling there is something paradoxical about being causally connected to unobservable regions of the universe. I will, however, allow that I may be a little too narrow minded of what constitutes being observable.

 

[ohwilleke]

Chronos, I see the intuition your getting at and in the same vein wonder if the effect Wiltshire proposes doesn't imply superluminal gravitational action.

 

[Kea]

Just Out

Exact model universe fits type IA supernovae data with no
cosmic acceleration
B.M.N. Carter, B.M. Leith, S.C.C. Ng, A.B. Nielsen, D.L. Wiltshire
http://www.arxiv.org/abs/astro-ph/0504192

9 pages, 5 figures, aastex

Abstract:
The unexpected dimness of Type Ia supernovae at redshifts z <~1 has over the past 7 years been seen as an indication that the expansion of the universe is accelerating. A new model cosmology has been proposed by one of us [gr-qc/0503099], based on the idea that our observed universe resides in an underdense bubble remnant from a primordial epoch of cosmic inflation. Although there is no cosmic acceleration, it is claimed that the luminosity distance of type Ia supernovae data will nonetheless fit the new model, due to systematic effects. In this paper the hypothesis is tested statistically against the available type Ia supernovae data by both chi-square and Bayesian methods. The model gives good agreement if the density parameter, Omega_0, is taken to be the density in ordinary baryonic matter only. If low Omega_0 parameter values are accepted, then the model would dispense with both dark energy and non-baryonic dark matter, and an alternative explanation would be required for galaxy rotation curves and dynamical measurements of Omega_0 on the scales of clusters of galaxies.

 

[ohwilleke]

If low Omega_0 parameter values are accepted, then the model would dispense with both dark energy and non-baryonic dark matter, and an alternative explanation would be required for galaxy rotation curves and dynamical measurements of Omega_0 on the scales of clusters of galaxies.

:!) It will be very interested to see what informed reviews have to say about this theory. or or or

But, enough with the decedant smilies already. :tongue2:

 

[Kea]

The following webpage is under construction:

Open Bubble Model Cosmology by D.L. Wiltshire

http://www2.phys.canterbury.ac.nz/~dlw24/universe/

 

[Kea]

New

New versions now available:

http://www2.phys.canterbury.ac.nz/~dlw24/universe/

Greetings
Kea

 

[Kea]

new paper

Structured FRW universe leads to acceleration: a non-perturbative approach
Reza Mansouri
http://www.arxiv.org/abs/astro-ph/0512605

From abstract:
We propose a model universe in the matter dominated phase described by a FRW background with local inhomogeneities, like our local patch, grown out of the primordial fluctuations. Our local patch consisting of different structures is approximated as an inhomogeneous cosmic fluid described by a LTB metric embedded in a background FRW universe. Within the exact general relativistic formulation, the junction conditions for the only possible matching without a thin shell at the boundary, neglected so far in the literature, constrains the model in such a way that the luminosity distance-red shift relation mimics a FRW universe with dark energy. Therefore, the dimming of SNIa is naturally accounted for in such a structured FRW universe.

 

[Chronos]

I read that paper and agree it's an interesting idea, Kea. It appears not to require those annoying, ad hoc parameters.