Re: Cosmic acceleration rediscovered
From: greywolf42 (mingstb_at_marssim-ss.com)
Date: 01/05/05
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Date: Wed, 05 Jan 2005 20:40:14 GMT
Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message
news:crdq0k$eo0$1@news.urz.uni-heidelberg.de...
> Greg Hennessy wrote:
> > In article <SV1Cd.203$XZ.167@news.flashnewsgroups.com>,
> > greywolf42 <mingstb@marssim-ss.com> wrote:
> >
>
> [snip]
>
> >>>>Specifically, all instruments up to and
> >>>>including COBE found no variations from pure thermal down to the
> >>>>physical resolution of the instruments.
> >>>
> >>>Have you even *READ* the COBE papers?
> >>>http://aether.lbl.gov/www/projects/cobe/dmr_final_apj.ps
> >>>
> >>><begin quote>
> >>{snip quote that did not even mention the stated issue}
> >>><end quote>
> >
> > You snipped the part where it COBE found variations in the data,
> > something you claimed it didn't find.
>
> Probably he simply did not understand that your quote addressed
> the issue.
Feel free to provide the excerpt that the claimed results (1 in 100,000)
were below the physical resolution of the instruments (1 in 10,000).
> [snip]
> >>>When you try to measure the precise spectrum of
> >>>a hydrogen atom to test quantum mechanics, you need corrections
> >>>predicted by quantum theory.
> >>
> >>I agree with you. That is a major failing of the claims of QM. They
> >>are circular.
> >
> > Those are not circular.
>
> And here greywolf nicely demonstrates that he does not understand
> science at all.
The classic special plead fallacy.
> [snip]
>
> > CMBR photons pass through a region of hot gas, and get inverse compton
> > scattered. The photons are black body before, but since the inverse
> > compton effect conserves photon number, but adds energy, the photons
> > are no longer strictly black body. The spectrum of the photons is
> > changed as indicated by
> > http://nedwww.ipac.caltech.edu/level5/Birkinshaw/Birk3_3.html. At some
> > wavelengths the specific intensity is lower, at some it is higher. The
> > amount of change of the spectrum is related to the number density of
> > the electrons, but not the distance from the hot gas to the
> > observer. This last sentence is very important.
>
> If, after the scattering, there is not a black body spectrum
> anymore, why does it make sense to talk about a change in temperature?
It doesn't, of course.
> You address this partly below, but I still don't understand this
> entirely.
It's merely sloppy terminology.
> [snip]
>
> >>Temperature is measured by the *overall* spectrum ... not by an
> >>arbitrary slice of it!
> >
> > Temperature is only defined for a system in equilibrium. The photons
> > are not in equlibrium after being inverse compton scattered, hence
> > don't follow the black body curve.
>
> Why does it make sense then to talk about the change in
> temperature???
It's merely sloppy terminology.
> > For any specific wavelength, a
> > temperature can be calculated from the observed specific intensity via
> > B = 2 nu^2 kT/c^2.
> >
> > http://scienceworld.wolfram.com/physics/BrightnessTemperature.html
>
> Only valid in the Rayleigh-Jeans region of the Planck curve.
> Since the photons do not have a black body spectrum anymore,
> why is it valid to use that formula?
>
It's merely sloppy terminology.
>
> [snip]
>
> >>And confused temperature decrements with intensity decrements.
> >
> > For a black body they are related.
>
> But after the scattering, there *is* no black body spectrum
> anymore!
Bingo.
> [snip]
>
> >>>but it also has observations in 1996 that
> >>>show values of -0.24 ± 0.04 and -0.37 ± 0.07,
> >>
> >>The units are delta T's in milliKelvin.
> >>
> >>>both of which are statistically significant.
> >>
> >>All the "statistically significant" claims require detection of
> >>variations of temperature on the order of 10 to 100 microKelvin.
> >>Thats 1 part in 10,000 to 100,000 of the CMBR temperature.
> >>Which is the pure noise region.
> >
> > Who says it is the pure noise region?
COBE.
> Apparently greywolf, who is, as well all know, an expert on
> radio astronomy and error analysis...
At least this ad hominem is ironical.
> Sometimes his arrogance leaves me really speachless!
Ah, IF ONLY!
> > Yes, these are measurements of
> > small numbers. But with modern detectors, and careful error analysis,
> > you can still make a statistically significant detection.
>
> I wonder what greywolf thinks the "+- 0.04" and "+- 0.07"
> above mean, and what "statistically significant" means...
It depends upon what the measurement is, of course.
> [snip]
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail}
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