Witam,
"Healthy skepticism of humbug?"
"humbug" is definitely unfair. Alain is a cool guy and a sincere scientist. Narlikar, Burbidge (and the late Hoyle) are (was) good scientists, and they are (was) right to criticise the monothink (pensée unique) and the fashion of talking about cosmology in a way which seems simple but in fact is misleading regarding what we have really measured.
I hope Alain has enough stamina to keep struggling for his favorite model of Omega_m \approx 1 as long as Narlikar, Burbidge and Hoyle have struggled in favour of their model. But just as they brought out the quasi-steady state model, I guess Alain will come up with the quasi-Omega_m=1 model... ;)
I'm happy to see that on page 4, Alain has taken notice of my repeated insistence that approximately flat is not exactly flat, and that the present results can be approximately expressed as:
R_C = c/ [H_0 (|Omega_total - 1|)^1/2] > R_Horiz \approx 10h^-1 Gpc
or more vaguely as R_C > c/H_0 .
The footnote "a" is rather poorly written - the FLRW model is a mathematical model. It is still true in cosmology that space is either flat or it is not flat, the mathematics is still correct.
But saying "nearly flat" is a good habit - it's simply honest. Just as the Earth has a nearly flat surface, the Universe seems to be nearly flat.
Still on the philosophy of science aspect, I should remind people that it's rather inconsistent of Alain to insist on empirical measurements when he considers empirical measurements of the global cosmological parameters to be a low priority.
However, it remains that to ignore dissidents in astronomy is extremely hypocritical - we all know the history of astronomy. In the birthplace of Copernicus, we should be perfectly aware of this!
*measurements*
This is the most interesting bit, especially Fig 4 page 10. This is where OCRA measurements from the SZ survey will be interesting.
They should hopefully give us independent estimates of the different luminosity functions of clusters at different redshifts.
Whatever the explanation for Alain's analysis is, we're going to have to understand it sooner or later if we want to get anything useful from OCRA. My own guess is the non-Gaussianity of the tail of the perturbation distribution, but until I start trying some calcuations, I can't really say anything seriously.
BTW, I'm copying this to Alain just in case he feels like commenting. (The .htaccess file fails so cosmo-torun became an open list de facto, unless someone is really paranoid I suggest we keep it open.)
pozdrawiam Boud
[fr] Salut Alain, si tu souhaites savoir ce que fait notre petite équipe, veuille aller sur :
http://adjani.astro.uni.torun.pl:9673/zwicky/TCfACosmology
La page sur OCRA se trouve ici, mais nous n'avons rien mis pour l'instant sauf un lien vers quelques jolies images :
http://adjani.astro.uni.torun.pl:9673/zwicky/OneCmRA
Tu peux répondre sans ętre abonné, mais il faut confirmer au robot par la suite.
Amitiés Boud
On Thu, 9 Jan 2003, Andrzej Marecki wrote:
Paper: astro-ph/0301137 From: Blanchard Alain <alain.blanchard at ast.obs-mip.fr> Date: Wed, 8 Jan 2003 17:45:24 GMT (138kb)
Title: Cosmological Parameters: Fashion and Facts Authors: A. Blanchard (LAOMP, Toulouse)
Abstract: [...] I would like to emphasize that some results are established beyond reasonable doubt, like the (nearly) flatness of the universe and the existence of a dark non-baryonic component of the Universe. But also that the evidence for a cosmological constant may not be as strong as needed to be considered as established beyond doubt. In this respect, I will argue that an Einstein-De Sitter universe might still be a viable option. Three global tests: 1) the evolution of the abundance of clusters with redshift 2) the baryon fraction measured in local clusters 3) apparent evolution of the baryon fraction with redshift might be consistent with a high matter density for the Universe in the range $0.6-1.$. I therefore conclude that the dominance of vacuum to the various density contributions to the Universe is presently an interesting and fascinating possibility, but it is still premature to consider it as an established scientific fact.
Andrzej