SNe Ia, Implications, Interpretations, Lambda-CDM...

[modest]

Nice.

I'd say this fits my previously formed conclusion:

Originally Posted by modest

Our cosmic observations do indeed agree with the FLRW metric if the makeup of the universe is currently 74% vacuum energy density and 26% mass density as a ratio to the critical density. Either this is not the makeup of our universe, the universe is not homogeneous and isotropic, or FLRW and by extension GR are wrong.

If there is no dark energy and yet cosmic solutions to General Relativity are correct then one possible reason would be an inhomogeneous cosmos.

~modest

[coldcreation]

Originally Posted by modest

Nice.

I'd say this fits my previously formed conclusion:

If there is no dark energy and yet cosmic solutions to General Relativity are correct then one possible reason would be an inhomogeneous cosmos.

~modest

Hello again,

I've been off-line fossil hunting for a while...

Yes modest, I remember your sentence. Indeed, the homogeneity assumption is required by the concordance model.

Here, interestingly enough, there is an article that does not require spatial inhomogeneity (as in my previous post) to refute the accelerated expansion hypothesis. I have not yet read the entire work but I did notice a few points:

Modeling The Expansion Of The Universe By A Steady Flow Of Space-Time, by Juan Casado Giménez Universidad Autónoma de Barcelona

Assuming that the Universe is spatially infinite, we depict a
simple model where gravitation does not decelerate the
expansion, which occurs at constant speed for any two distant
galaxies. This Steady Flow model fits the SNe Ia observations
without a repulsive dark energy. [...]


Conclusions: In a homogeneous, isotropic and spatially infinite Universe the net gravitational force on any galaxy should be (almost) null for
symmetry reasons. Thus, gravitation does not decelerate the universal
expansion, which follows a steady Hubble flow with constant
recession velocities. The results of SNe Ia are consistent with this
simple model for a commonly accepted value of H0 and without any
free fitting parameters. Neither cosmological constant nor a repulsive
dark energy are required in our model. The horizon problem vanishes
since the Universe should have been always spatially infinite and
homogeneous. The flatness problem is avoided because of the lack of
any spatial curvature (except at local scale) due to the overall
cancellation of the gravitational field. The time evolution of the scale
factor, R ∝ t, is specific of our model and is the same independently
of either radiation or matter dominance in the Universe.
Subsequently, we obtain longer times for the development of
structure seeds observed in CBR and for the formation of the first
galaxies. On the other hand, the steady expansion time coincides with
the age of the Universe obtained from the Concordance model, and
some other features of Big Bang cosmology, such as the evolution of
temperature with the scale factor or the primordial nucleosynthesis of
He, remain unchanged.

On a slightly different note, let's consider for a moment the contents of the universe as an ideal expanding gas. The objects (galaxy clusters in this case) within the universe expand adiabatically.

Clouds of hydrogen condense under gravitational interactions to form stars (star-clusters, galaxies, galaxy clusters, superclusters). Stars light up and heat the universe. The CMB grows warmer with time. As the undifferentiated matter heats, like gas, expansions occurs.

Note that within this latter scenario there is no need to have a big bang at any time in the past, nor any dark energy or CDM...

Just a thought...



CC

[Pluto]

G'day from the land of ozzzzzzz

This paper fits to your discussion

Observations of type 1a supernovae are consistent with a static universe

Jan-09

Observations of type 1a supernovae are consistent with a static universe
http://adsabs.harvard.edu/cgi-bin/np...y?bibcode=2009
arXiv0901.4172C&link_type=PREPRINT&db_key=PRE

Analysis of type 1a supernovae observations out to a redshift of $z$=1.6 shows that there is good agreement between the light-curve widths and $(1+z)$ which is usually interpreted as a strong support for time dilation due to an expanding universe. This paper argues that a strong case can be made for a static universe where the supernovae light-curve-width dependence on redshift is due to selection effects. The analysis is based on the principle that it is the total energy (the fluence) and not the peak magnitude that is the best `standard candle' for type 1a supernovae. A simple model using a static cosmology provides an excellent prediction for the dependence of light curve width on redshift and the luminosity-width relationship for nearby supernovae. The width dependence arises from the assumption of constant absolute magnitude resulting in strong selection of lower luminosity supernovae at higher redshifts due to the use of an incorrect distance modulus. Using a static cosmology, curvature-cosmology, and without fitting any parameters the analysis shows that the total energy is independent of redshift and provides a Hubble constant of $63.1\pm2.5$ kms$^{-1}$ Mpc$^{-1}$. There is no indication of any deviation at large redshifts that has been ascribed to the occurrence of dark energy.

[Little Bang]

All of this thread is based on the Hubble redshift. I have what I consider to be proof of tired light. Does the wavelength of light propagating into a gravity well get shorter? Yes, does the wavelength of light propagating out of a gravity well get longer? Yes, can the Universe be considered a gravity well? Yes.

[coldcreation]

Originally Posted by Little Bang

All of this thread is based on the Hubble redshift. I have what I consider to be proof of tired light. Does the wavelength of light propagating into a gravity well get shorter? Yes, does the wavelength of light propagating out of a gravity well get longer? Yes, can the Universe be considered a gravity well? Yes.

Hi Little Bang,

I'm not sure whether your post belongs in this thread, the Redshift z thread, the Alternative Theory forum or Strange Claims.

This concept of yours seems to require a center of gravity, a gravitational well of some sort, located at the center of the universe preferably. Is that correct?

Note that this idea is not called tired light; which has been shown not to be wavelength independent, thus in conflict with observations.

This idea is something more along the lines of Ellis, G.F.R, (1977), where redshift z may be seen in terms of cosmological gravitational redshifts. And where the universe might be dominated by some form of ‘massive neutrinos’ in the form of ‘gravitational waves’ which would then be added to the mass energy content estimate, with a non-zero value for the cosmological term. Otherwise there seems to be not enough mass to cause the observed frequency shifts toward the red end of the spectrum.

In another way, frequencies are lengthened due to the gravitational potential of the constituents in the universe that produce spacetime dilation from our frame of reference.

Here is the entire reference: Ellis, G.F.R. 1977, Is the Universe Expanding?, General Relativity and Gravitation, Vol. 9, No. 2 (1978), pp. 87-94

It's not an easy publication to find. I was able to locate it an obscure library somewhere between La tour Eiffel and Musée d'Art Moderne de la Ville de Paris. It was actually Halton Arp, after one of our discussions, that gave me the reference.

CC

[Little Bang]

My post assumes there was a beginning, a BB. If that is true then the point of origin would be the center of gravity. I well look at your link and get back to you.

[Little Bang]

CC, the link suggests your own semi static Universe can work but I'm not going to debate that issue because I don't know how you can get away from the infinite arm of gravity. Since in my opinion I have just shown the Hubble red shift to be invalid the Universe is not experiencing an accelerated expansion which means it must be slowing down or may have already started collapsing. This collapse also includes all the radiation from the BB which will loop around back to the point of origin somewhat like magnetic field lines. I realize the implications of what I say are devastating to cosmology and physics and will never be accepted but I"m not here to change science, I'm here to have fun.