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Re: Confused about redshift and age of stars

Subject: Re: Confused about redshift and age of stars
From: "Thomas Smid"
Date: 17 Jun 2006 04:43:15 -0700
Newsgroups: sci.astro
Craig Markwardt wrote:

> "Thomas Smid" <thomas.smid@xxxxxxxxx> writes:
> > Craig Markwardt wrote:
> >
> > > "Thomas Smid" <thomas.smid@xxxxxxxxx> writes:
> > > ...
> > > >
> > > > I am suggesting that it is *only* the electric field that causes this.
> > > > Otherwise, it would hardly be able to cause a redshift in intergalactic
> > > > space as the distance between two particles is larger than the length
> > > > of a 'photon'.
> > > > With regard to the deflection, which I specifically treated on my page
> > > > http://www.plasmaphysics.org.uk/research/lensing.htm : as mentioned
> > > > there, the electric field around the sun should have a strength of
> > > > about 10^-6 V/m (due to the sun being positively charged at a potential
> > > > of about 1 kV) However, it extends over about 10^6 km , so you need
> > > > correspondingly higher field strengths for lab dimensions. If you
> > > > assume a quadratic dependence (as suggested on my webpage), then you
> > > > find that you would need lab field strengths of the order of the
> > > > inner-atomic field, which are obviously impossible to create (as it
> > > > would tear the whole lab apart at the same time) . The whole effect is
> > > > thus very much associated with astronomical distances and it is
> > > > therefore not surprising that it is unknown in classical mainstream
> > > > physics.
> > >
> > > However, there are very significant problems with non-cosmological
> > > redshifts.  As I noted in sci.astro.research article
> > > <mt2.0-2096-1113304780@xxxxxxxxxxxxxxxxxxxx> in reply to Robin Whittle,
> > >
> > >  : A non cosmological theory of redshifts would have a lot of serious
> > >  : problems to address, namely,
> > >  :
> > >  : * how cepheid variable stars, which have a known period-luminosity
> > >  :   relationship in the local universe, would have a period-luminosity
> > >  :   relationship in redshifted galaxies which is exactly tuned to the
> > >  :   redshift of the galaxy?  I.e.  how would each cepheid know to tune
> > >  :   its luminosity to the intrinsic redshift of the galaxy?
> >
> > I assume you are referring here to an effect similar to the delay of
> > supernova light curves.
>
> Actually, I'm not.  You are welcome to investigate cepheids and the
> related Hubble key project.

The redshift mechanism suggested by me would also result (on average)
in a linear redshift-distance relationship, so it doesn't make any
difference for the cepheid observations.

>
> > ... I have covered this on my page
> > http://www.physicsmyths.org.uk/redshift.htm . Basically, in general, if
> > a 'stretching' of the light wave (by whatever mechanism) leads to a
> > redshift, this is also likely to be associated with a reduction of the
> > amplitude of the wave i.e. a reduction in its intensity (additionally
> > to the usual 1/r^2 decrease). This leads therefore to an
> > underestimation of the absolute luminosity of the object.
>
> I note that there is no specific mechanism cited for either the
> wavelength "stretching" or amplitude decrease.

>
> > >  : * how could the Lyman alpha forest exist?  I.e. how could absorption
> > >  :   systems be seen at multiple intervening redshifts, but not at higher
> > >  :   redshifts?
> > >  :
> > >  :   http://www.astro.ucla.edu/~wright/Lyman-alpha-forest.html
> > >  :
> > >  : * if redshift is intrinsic to the host galaxy, how could the *same*
> > >  :   Lyman alpha absorption system appear in two *different* galaxy
> > >  :   spectra, which are on nearby lines of sight?
> > >  :
> > >  :   Young, P. A., Impey, C. D., Foltz, C. B. 2001, ApJ, 549, 76
> > >  :
> > >  : * for Arp-like theories where the redshift is intrinsic to the
> > >  :   galactic nucleus, how could maser systems exist distinct from the
> > >  :   nucleus which have the same redshift as the nucleus?
> > >  :
> > >  :   Kondratko, P. T., Greenhill, L. J.,  Moran, J. M. 2005, ApJ, 618, 618
> > >  :   Herrnstein, J. R. et al. 1999, Nature, 400, 539
> > >  :   Yates, J. A. et al 2000, MNRAS, 317, 28
> > >  :
> > >  : * for non Arp-like theories, where the redshift is created in the
> > >  :   neighborhood of the galaxy by some gas or plasma, how could the
> > >  :   redshift "process" -- whatever it is -- physically generate
> > >  :   indentical redshifts at both microwave and optical wavelengths?
> > >  :   I.e. all electromagnetic processes I am aware of are highly
> > >  :   chromatic.
> >
> > These points do not apply to my theory as it assume that the redshift
> > is distance related (i.e. produced progressively on its way from the
> > object to the observer due to the effect of the intergalactic plasma).
> >
> > >  :
> > >  : * for that matter, how could any "plasma effect" shift the wavelength
> > >  :   of emission, without doing other things like line broadening?
> > >  :   I.e. why aren't high redshift lines also highly broadened?
> >
> > This would only apply in case of a scattering, but not for a mechanism
> > that can be compared to refraction. As shown on my page
> > http://www.plasmaphysics.org.uk/redshift.htm , the 'blurring' of the
> > signal can be completely neglected here.
>
> So what is this mechanism exactly?  Your web page only suggests "if
> this were possible" type scenarios, but no specific mechanism.  I
> suspect that there is no detailed theory behind the wishful scenario.

The exact 'mechanism' could be worked out if the effect is studied in
more detail. At the moment I am just suggesting as a theoretical
possibility that the redshift and bending of light is associated with
electric fields. The fact that this doesn't naturally follow from other
physical laws doesn't logically rule it out. There will always be
physical effects as yet unknown that can not be explained within
present theoretical frameworks.

>
> > >  :
> > >  : * why the cosmic microwave background in the high redshift universe
> > >  :   was apparently hotter?
> > >  :
> > >  :   Molaro, P., et al. 2002, A&A, 381, L64
> > >  :   Silva, A. I. & Viegas, S. M. 2002 MNRAS, 329, 135
> > >  :   Srianand, R. Petitjean, P. & Ledoux, C. 2000, Nature, 408, 931
> >
> > I had a look at two of  the papers and I think this should not really
> > count as hard evidence.
>
> Interesting and ironic, given your own lack of hard evidence.

I am suggesting my theory merely as a proposal, but these papers
misleadingly suggest that their data would be evidence for an increase
of the CMB temperature. This is by no means the case, as one can see
for instance from Fig.5 in Srianand et al. (see
http://www.plasmaphysics.org.uk/imgs/srianand.gif ). I have allowed
myself here to make this plot somewhat clearer by putting explicit
error bars to those measurements that merely were estimates of upper
limits (and I also corrected the figures on the temperature scale which
originally read 30-20-30). First of all, since the COBE measurement at
z=0 has nothing to do with the type of analysis at question here, it
should not serve as a further constraint for the data, and without it
almost any curve could be a fit, for instance a constant temperature of
8 K (the long-dashed line that I put in additionally). The latter
possibility would then of course indicate that the observed  fine
structure excitations are not related to the CMB at all.


> > ... There are a lot of assumptions and estimates
> > being made which are based on observations within our own galaxy and
> > thus may not be appropriate for QSO's. ...
>
> Again, interesting in light of your own unsubstantiated assumptions
> and estimates.  The papers I cited have quite extensive citations
> themselves.  You could have checked this out, but apparently you did
> not.

>
> > ... The excitation of certain fine
> > structure transitions may well be due to local microwave sources for
> > instance. ...
>
> True, but these papers also consider those possibilities and estimate
> the contributions of local sources.  Do you have a substantiated
> correction to that?
>
> > ... Also, they may have underestimated the excitation due to
> > collisions by electrons by assuming the latter to be in LTE with the
> > ions and neutrals. This assumption is far from correct for most space
> > plasmas as photoelectrons usually recombine before they thermalize
> > owing to their small mass (see for instance my own numerical
> > calculation for the ionospheric electron spectrum at
> > http://www.plasmaphysics.org.uk/research/elspec.htm ).
>
> Some of these factors are discussed in the papers.  Meanwhile, you
> have provided no quantitative counterargument.

The physical assumptions made in these papers are very much
inappropriate and thus effectively invalidate the analysis:

1) There is no way that photoelectrons of around 10 eV could lose
sufficient energy such as to end up with a kinetic temperature of
around 10^-2 eV (100K)  (as assumed in these papers). Due to the mass
ratio of the electrons and neutrals, this would take more than 10^4
collisions, but in the meanwhile the electrons will have long
recombined. To a certain extent this may be offset if the neutral
density is several orders of magnitudes higher than the plasma density
(which it is in many cases and presumably also here), but the point is
that the recombination probability increases towards smaller energies
like E^-1.2 (E^-1.7 for the recombination cross section (see
http://www.plasmaphysics.org.uk/research/recrsect.htm ) and E^0.5 for
the velocity; for more details see Eq.(A.2.17) in
http://www.plasmaphysics.org.uk/papers/radscat2.htm ). So the
recombination probability will steadily increase as the electron energy
degrades, and the electrons will recombine way before the energy has
decreased to 10^-2 eV.

2.) It is assumed in these papers that the fine-structure levels are
populated according to a Boltzmann distribution. This would require
that elastic collision time scales are shorter than the life time of
the levels. Taking the values assumed here, the elastic collision time
scale with neutrals would be about 10^10 sec. I am not familiar with
the details of the transitions involved here, but it seems unlikely to
me that the lifetime of the levels is any longer than this, even if the
transitions are dipole-forbidden (in case of the Carbon transitions,
which are electronic transitions, it would anyway only be electrons
that could lead to an energy exchange as neutrals could not transfer
enough energy due to the mass difference; this would make the
collisional time scale even longer due to the smaller density of
electrons).

3.) The figures used in the papers do in fact not add up at all:  in
Ge,J., Bechtold,J. and Black,J.H. , Ap.J. 474, 72 (1997) for instance,
the H-ionization photon flux appropriate for the observation is given
as about F= 10^8 ph/cm^2/sec .  On the other hand, the neutral density
is taken as N=10 cm^-3  and the electron density as n=10^-2 cm^-3. Over
the ionization-recombination equilibrium condition   F*Q(ion)*N =
alpha*n^2 , one would thus obtain (using a photoionization cross
section Q(ion)=10^-17 cm^2)  a value for the recombination coefficient
of alpha=10^-4 cm^3/sec  which is a completely unfounded value (usually
it is between 10^-8 - 10^-12  cm^3/sec depending on the assumptions).

>
> > I am also missing any observations that would correspondingly derive a
> > temperature of 2.7 K from objects within our own galaxy (where the
> > physical conditions are obviously much better known).
>
> You mean like these?
>
> Herzberg, G. 1950, *Molecular Spectra and Molecular Structure*,
>   v. 1, 2nd Ed., (van Nostrand: Princeton, NJ)  -- p. 496
> McKellar, A. 1940 PASP 52, 187
> McKellar, A. 1941, Publ Dominion Astrophys. Obs., Victoria, BC, 7, 251
> Thaddeus, P. 1972, Ann. Rev. Ast. Ap., 10, 305

No, actually I meant that the analysis of any of the methods used to
derive the CMB temperature in certain extragalactic objects is applied
identically to other objects including ones in our own galaxy. It is in
my opinion scientifically improper to apply any of these observational
methods basically only to one instance and then claim that these
provide mutual confirmation if they happen to yield the expected result
(especially in view of the physically questionable assumptions
addressed above).

>
> I should also mention that the redshift dependence of the CMB
> temperature has also been confirmed with galaxy clusters (Battistelli,
> E. S., et al. 2002, ApJL, 580, L101).

This is based on the Sunyaev-Zeldovich effect which I think is not yet
sufficiently observationally confirmed, because as far as I am a aware,
the predicted increase of the CMB intensity in the high frequency
region has not been observed yet at all. On the other hand, the
decrease for lower frequencies would also result from my own theory: as
mentioned already on my page
http://www.plasmaphysics.org.uk/research/redshift.htm , the plasma
should lead to electromagnetic waves gradually being 'scrambled' i.e.
their coherence and thus their apparent intensity being reduced (see
http://www.plasmaphysics.org.uk/photoionization.htm ). 

Thomas


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