Author: magnunPI

Big Bang or Many Bangs..:)

August 28, 2017

No.

The Universe Always Ring Ten Times..:)

February 25, 2017

Das Klingerln des Universums

February 8, 2017

Title

Second Peer Review - 3

November 22, 2016

But putting all of that aside, I will take a narrow view of the manuscript. It proposes a distance(redshift) relation, and we can quantitatively see how well this matches the data. The proper way to do this is not by making plots, it is to compute chi^2 values from the distance moduli (mu) and covariance matrix in Union2.1:  chi^2 = (mu_observed - M - mu_theory)^T . (covariance matrix^-1) . (mu_observed - M - mu_theory)  where M is a constant that can be fit (the host-mass relation can also be fit, but failing to do so won’t affect the results much). After computing chi^2 values for LambdaCDM and HU, you can see if HU is favored or disfavored by the data compared to LambdaCDM. By my eye, HU is significantly worse, but the chi^2 values will say for sure.

Second Peer Review - 2

November 22, 2016

I’m also skeptical that the luminosity of a SN Ia if G were different would scale as G^-3 (or M_ch^2).

Second Peer Review - 1

November 22, 2016

This manuscript presents the predicted luminosity distance in the Hypergeometrical Universe (HU) model and compares against the Union supernova compilation. Unfortunately, I do not believe that it is suitable for publication. I detail (only the major) issues below.

First Peer Review - 9

November 22, 2016

So overall, I am not convinced that the author has properly calculated the actual impact of the geometry of the universe that he proposes. Since he is not modifying physics in a fundamental way, but only the geometry (which is arguably the appeal of his model), many experiments in physics can be reinterpreted in terms of this new setup. As far as I can tell, they would not allow the set up to be possible. Thus unless the author can convincingly prove that the standard well known local physics is not modified in his setup, it is premature to try to calculate the impact on cosmology.

First Peer Review - 10

November 22, 2016

* Finally, I do not think it is possible for G to vary in the way that the author proposes. For one, we have constraints on the variation of G on Earth from the Oklo natural nuclear reactor and, going back further into the past, from Big Bang Nucleosynthesis which mean that if cannot have change by more than a few percent. If it were changing together with Hubble, we would find that the galaxies and orbits destabilise etc. Moreover, as the author notices, stars are very sensitive to the strength of gravity (e.g. arXiv:1102.5278) and we would have know about such variations.

First Peer Review - 8

November 22, 2016

The rest of the paper in fact makes use of some simple geometrical arguments to obtain distances and I have to admit I do not understand what they refer to. Proper null geodesics of the metric must be calculated to be able to say anything about distances.

First Peer Review - 7

November 22, 2016

* I do not understand why the author uses the standard equation for luminosity distance in LambdaCDM cosmology (calling it the "improved Hubble law"). This fundamentally assume an FRW geometry in 3 spatial dimensions, with the cosmological constant and non-relativitistic matter as the only sources of energy in the universe. If the author would like to make claims about how well supernovae fit his model, he should start with a metric and with a definition of how light propagates (e.g. on null geodesics in standard physics). Given the metric and its dynamics which one would obtain by solving Einstein equations, an equation for the luminosity distance-redshift relation can be derived. It would be different.

First Peer Review - 6

November 22, 2016

* The recent detection of gravitational waves by LIGO confirms that we understand reasonably well the generation and propagation of these waves on cosmological distances. For the reason explained above, they would also have been sensitive to the full 5D structure of the space time and therefore their luminosity would have been completely different in such a 5D setup.

First Peer Review - 5

November 22, 2016

* Even if one were to brush this off as some sort of new physics (e.g. inspired by open string theory), gravity must know about the extra dimensions. Again, we know with excellent precision that the force of gravity in the solar system falls off as 1/r^2 and therefore it is 3+1 dimensional. It is possible to have a model of gravity which is 4D at small distances but sensitive to the full 5D space at large distances (see the Dvali-Gabadadze-Porrati model) but this means that the universe behaves in a completely standard way until the acceleration era. This is not what the author has in mind and comes with its own inconsistencies (ghosts etc) which have not been solved.

First Peer Review - 4

November 22, 2016

Models of this type were studied extensively in the late 90s/early 2000s under the guise of braneworlds (see e.g. the Randall-Sundrum model), but the extra dimensions were compact in order to prevent the existence of low-mass Kaluza-Klein modes. The size of this extra dimension would have to be microscopic, of the order of inverse TeV in order to avoid this problem.

First Peer Review - 3

November 22, 2016

continuation of First Peer-Review

First Peer Review -2

November 22, 2016

continuation of First Peer Review:

First Peer Review -1

November 22, 2016

Reviewer 1

HU Rebuttal Letter

November 22, 2016

Dear Dr. Rhode,

Hurray HU has a Peer-Review

November 22, 2016