Marmet explains this quite simply as being due to the amount of
intervening matter and is the result that he expects - that light is
gradually redshifted in proportion to how many molecular interactions it
has as it travels through gaseous matter. This equation does indeed fit
Such an explanation, if accepted, also leads to the conclusion that a
cosmological redshift versus distance must occur. The expected
cosmological redshift would fit the observed cosmological redshift only
if the density of the universe were rather higher than present
estimates. Marmet explains this as being due to the difficulty in
observing molecular hydrogen. Of course there are other difficulties
with this explanation, such as time dilation of supernova.
I am particularly interested comments on the redshift associated with
the solar limb distance. Is this genrally accepted as inexplicable? Is
there any other possible explanation? Is Marmet's explanation considered
I vaguely recall reading something about a "horizontal redshift" being
proposed by someone some decades back but could not find anything
related to this with google. Can anyone comment on this also?
That may well be, within the Milky way. But one also has to take into
account possible MOND effects.
See also work being done in the galaxy. These surveys will give much
more accurate information.
OBSS, the "Origins Billion Star Survey"
Science goals listed here:
Note that these include:
Accurate measurement of the distance to the Galactic Center
Measurement of the Galactic rotation curve
also GAIA http://www.esa.int/esaSC/120377_index_0_m.html
>Such an explanation, if accepted, also leads to the conclusion that a
>cosmological redshift versus distance must occur.
This phenomenon is not cosmological red shift.
>cosmological redshift would fit the observed cosmological redshift only
>if the density of the universe were rather higher than present
>estimates. Marmet explains this as being due to the difficulty in
>observing molecular hydrogen. Of course there are other difficulties
>with this explanation, such as time dilation of supernova.
>I am particularly interested comments on the redshift associated with
>the solar limb distance. Is this genrally accepted as inexplicable? Is
>there any other possible explanation? Is Marmet's explanation considered
I don't know about his explanation, but I am not especially impressed by
his site. This type of explanation for supernova redshifts has been well
analysed and refuted in the literature.
Please reply by name
> Such an explanation, if accepted, also leads to the conclusion that a
> cosmological redshift versus distance must occur.
Of course, there is a relation between cosmological redshift and
distance in standard cosmology.
Presumably, you mean that this theory could have a cosmological redshift
with no expansion. However, if the universe is static, you have to
explain WHY it is static.
> Presumably, you mean that this theory could have a cosmological redshift
> with no expansion. However, if the universe is static, you have to
> explain WHY it is static.
Perhaps I did not explain Marmet's argument well (I kind of assumed that
people would read it on his web site). He states that the passage of
light through a gas will gradually redshift all spectral lines,
depending on the density of the gas and distance travelled.
This is confirmed from the observation of the solar limb in comparison
to the centre of the sun's disk, as light from the limb has travelled
through more gas on its way to us. The curve that is observed is exactly
as expected by his prediction, and is inexplicable by standard physics.
If anyone disagrees with Marmet about this effect then they need to
explain how the observed curve results from standard physics.
Accepting this at face value (and I am asking if there is any reason not
to do so) then it makes a prediction that even in a static universe
there will be a redshift versus distance relationship. So yes, it leads
to a static universe being a very real possibility.
I wouldn't state as you do that there is a cosmological redshift with no
explanation. The redshift is explained by the interaction of light with
matter. Marmet claims that because the interaction of light with matter
is non-linear then it is also inelastic and so must be redshifted. He
states that this is in accord with and therefore expected from standard QM.
I don't know what you expect for an explanation of why the universe is
static. If correct physics shows that the cosmological redshift must be
expected even in a static universe (i.e. non-expanding universe) then I
can see no argument against it. The question is whether his evidence
concerning solar limb redshift is correct and that is what I am asking.
It would seem to me that this effect could be tested on earth by passing
light through gas for long distances and comparing the resulting
wavelength to the original. Does anyone know if any such experiment has
been done? I seem to recollect a discussion a couple of decades ago
about a proposed "horizontal redshift" or something like that.
Why, or how?
A cosmological constant? (Which has already come back into fashion).
Though a static universe poses a whole range of new problems.
Going back to Ray Tomes's post, Marmet's theory means the universe could
be expanding more slowly than it appears to be, while the density is
actually what is observed (hope that makes sense ;-)
Not a very elegant solution, though.
Mail to jsilverlight AT merseia DOT fsnet DOT co DOT uk is more likely to be
>Accepting this at face value (and I am asking if there is any reason not
>to do so)
There is, because most of the stuff on his site leads one to believe
that Marmet is not capable of carrying out a correct calculation. As I
am not an expert in the particular observations his is discussing I am
not going to do a calculation myself. I think it would take me well over
a month to bring myself up to speed on the literature and everything I
would need to know to do such a calculation correctly. As far as I can
tell, Marmet does not appear to have done this himself, so I have no
confidence in his results.
>then it makes a prediction that even in a static universe
>there will be a redshift versus distance relationship. So yes, it leads
>to a static universe being a very real possibility.
>I wouldn't state as you do that there is a cosmological redshift with no
>explanation. The redshift is explained by the interaction of light with
>matter. Marmet claims that because the interaction of light with matter
>is non-linear then it is also inelastic and so must be redshifted. He
>states that this is in accord with and therefore expected from standard QM.
Perhaps, but papers on cosmological observations on high redshift
objects already take such effects into account.
>I don't know what you expect for an explanation of why the universe is
>static. If correct physics shows that the cosmological redshift must be
>expected even in a static universe (i.e. non-expanding universe) then I
>can see no argument against it. The question is whether his evidence
>concerning solar limb redshift is correct and that is what I am asking.
>It would seem to me that this effect could be tested on earth by passing
>light through gas for long distances and comparing the resulting
>wavelength to the original. Does anyone know if any such experiment has
>been done? I seem to recollect a discussion a couple of decades ago
>about a proposed "horizontal redshift" or something like that.
I would refer you to e.g. Riess astro-ph/0402512, who looks at differing
models of supernova redshift. But there is a huge literature in which
such effects are discussed. Marmet would only inspire confidence if he
appeared to be familiar with the literature. He does not.
But won't any such red shift be frequency dependent? Marmet's idea isn't
exactly new, but AFAIK it's never addressed this problem.
Really? A quick consultation of the literature suggests that it has
been known for decades that the solar limb redshift effect can be
explained by asymmetric absorption line profiles, viewed at different
angles. (e.g. Dravins Lindegren & Nordlund 1981)
In fact, the web site you refer to does admit that [ref. Marmet],
: ... One must conclude that the red shift resulting from
: bremsstrahlung, as predicted , , leads naturally to
: asymmetries of the type observed in solar spectra.
On the other hand, there is ample evidence for redshifts of a
cosmological nature. [eg. ref. Markwardt]
Dravins, D., Lindegren, L., & Nordlund, A. 1981, A&A, 96, 345
Usenet article: <mt2.0-2096...@hercules.herts.ac.uk>
His physical theory seems to be described at
but I find the discussion very confusing. According to equation 12,
the redshift depends on the temperature of something or other (the
emitting body?), but in individual galaxies stars of different
temperatures have the same redshift. In the case of emission or
absorption lines, it isn't clear to me how one would even define the
Leaving that aside, the column densities he requires are enormous.
Just after equation 19, he proposes a hydrogen volume density of 2.5E-2
cm^-3. For the Virgo cluster at 11 Mpc, that would give a column
density of 9E23 cm^-2, which would be completely opaque to soft X-rays.
Plenty of soft X-rays are observed from the Virgo cluster and indeed
from sources that are far more distant. On the other hand, there are
Galactic objects with column densities in the E23 range that do not
show substantial redshifts.
There is also the angular scattering problem, discussed in Section 3.2
of the web page. Frankly I don't understand his calculation at all,
but equation 23 suggests an angular size of 0.4 arcsec. The first VLBI
paper I ran across (Pott et al. 2005, AAp 438, 785) finds components 3
orders of magnitude smaller in a quasar at z=1.46.
I don't know much about the solar atmosphere, but I'd be astonished if
Marmet's theory has anything to do with cosmology.
Please see the section "Why isn't the required redshift observed?"
at my page: http://astroneu.com/plasma-redshift-1/ . The earliest
paper I know of in English is from 1916, in the Indian Kodaikanal
Observatory Bulletin XLIX, which the library there has kindly
provided me with a photocopy of:
On the Change of the Wave-length of the Iron Lines in Passing
From the Centre of the Sun's Disc to the Limb
J. Evershed and T. Royds
I have a PDF of this and links to other relevant papers at:
Probably the initial paper is:
=DCber eine bisher unbekannte Verschiebung der Fraunhoferschen
Linien des Sonnenspektrums
Halm, J. Astronomische Nachrichten, volume 173, p.273
Can anyone provide an English summary?
The redshift of lines at the limb could have a variety of
explanations, and the total explanation must involve consideration
of outflows (blueshift) at the centre of the disc, where in the
Sun's atmosphere the lines originate, and the effects we expect
from general relativity (gravitational redshift).
Most (all?) mainstream discussion on this matter ignores the
possibility that the light is redshifted by transit through a
sparse plasma or non-ionized gas. If such a process exists, then
we would expect greater redshift at the limb due to the light
passing through a larger distance of the low corona.
The late Paul Marmet had a redshift theory involving neutral
hydrogen. I couldn't figure out how this works, but it prompted
me to develop my own hypothesis.
Ari Brynjolfsson (http://arxiv.org/abs/astro-ph/0401420) has a
plasma redshift theory which I so far do not understand.
My tentative hypothesis may be easier to understand.
Below I discuss how such a redshift process (or maybe Ari
Brynjolfsson's) might behave. Although Ari Brynjolfsson
mentions "photons" I will assume that radiation is not quantized.
Plasma redshift involves stretching short coherence-length
electromagnetic radiation (emr) in time and longitudinal distance,
where the coherence length is generally shorter than the average
inter-particle spacing of the plasma (or maybe also neutral gas
in my hypothesis). These short coherence-length components
experience the medium as inhomogeneous - they are travelling
through vacuum most of the time, but occasionally encounter a
lone ion, electron, atom etc.
The wavefront carries energy and momentum. Anything which slows
it down, even temporarily, receives a fraction of that momentum -
at least temporarily. (Consider how a prism must temporarily
couple the momentum of a short burst of light which enters at one
face, changes direction, then changes direction again on exit.)
A wavefront encountering a cloud of gas or plasma (just like a
block of glass or a drop of transparent liquid) would be slowed
down as it enters and would kick back against the cloud as it
exits on the other side, regaining its full vacuum speed again.
A particle such as an ion is a cloud, albeit a very small one.
A cloud of any density at all above zero, including a large space
with a single particle, will slow the light down to some extent -
there is no inter-particle spacing large enough to completely
eliminate the slowing of light, so we must conclude that each
particle individually slows the wavefront, with the wavefront
travelling at full light speed in the vacuum between the
My hypothesis is that the wavefront temporarily couples some
momentum to the particle, and does not recover all this when it
kicks back against it, due to the (charged) particle being
accelerated and so losing some of this kinetic energy to the
surrounding space as emr.
The coherence length of the main black-body spectrum of white
light from the Sun is probably no more than 3 microns. I would
expect a redshift process to be quite noticeable at inter-particle
spacings exceeding this. The only trouble is that we can't really
detect such redshift, since it is likely to be slight, and we
don't have a way of analysing the photospheric light except by
looking at it through a putatively redshifting plasma. The
heating and acceleration of the solar corona and wind is not
explained by conventional theories:
Plasma redshift might explain this deposition of energy and
There is a huge range in inter-particle spacings from the
photosphere to the solar wind, and I think that the onset of
really intense heating in the transition region and low corona
coincides pretty closely (within this very large range) with the
inter-particle distances above a few microns, at which I expect
plasma redshift to occur.
It would be hard to investigate this redshift on Earth. Low
density plasmas could be made, but the redshift is so slight, and
only occurs with short coherence-length light - which makes the
actual redshift impossible to detect due to the broad spectral
characteristics of such light.
It might be thought that the redshift would move the entire
spectrum down, including the absorption lines. But that would
only be the case if we accept that the photosphere produces a
bunch of finely tuned "photons", that the absorption process weeds
out certain narrow bands of these, and that the subsequent
redshift process moves all the other "photons" down evenly.
We would not expect much plasma redshift of photospheric emission
lines in the solar corona, due to their coherence-length being
generally longer than the inter-particle spacing. I believe we
should not expect much redshift of the absorption lines either.
If we think of the light as a signal, the main part of the black
body spectrum can be represented adequately as lots of very short
wiggles (impulses), each with a short coherence length. Passing a
single one of these impulses through a band-reject filter - which
is what the absorption line process involves - results in a much
longer wiggle. I think the impulse response of the absorption
line filter creates a signal which has a much longer
coherence-length - and so which would be only very slightly
affected by passing through the sparse plasma in the low corona.
My tentative hypothesis is that the main light of the Sun is being
redshifted by about 1 part in 10,000, which provides the energy
budget needed to explain the heating and acceleration of the
solar corona. However, we have no way of observing this redshift
I guess that some emission and absorption lines which originate
below or within the transition region and low corona will be
subject to very much smaller redshifts, because they pass through
enough of the corona that the wavefront encounters some gaps
between particles which are comparable to its coherence length.
So this longer coherence-length wavefront, which carries the
signal which subtracts the absorbed wavelength from the total
signal, would occasionally be slowed down by isolated particles,
and so be subject to a slight amount of redshift, rather than
being continually slowed down (and so not redshifted at all) by
lots of particles all the time, as it is in the photosphere or
the Earth's atmosphere.
If that is the case, I would expect to see more redshift of lines
at the limb, because that light travels through a greater distance
of redshifting plasma in the low corona. I figure the high corona
and the wind is so sparse that it contributes little redshift -
and it is only at the limb that the light we see travels for a
significantly greater distance in the low corona.
There are a variety of processes discussed in the solar redshift
literature which may give rise to at least some of the observed
anomalous redshift at the limb. It would be a huge task to read
and understand all this material.
I think it may be possible to detect the effects of such a
redshift process on Earth. For instance a sparse gas of ionized
heavy gas atoms should be dragged (by the redshift depositing
energy and therefore momentum on each ion) by passing sunlight.
I figure focussed sunlight might push thoron or radon ions along
a glass tube, and so with inter-ion spacings of a few microns, we
might expect more radioactivity at one end of the tube.
Alternatively, an experiment on a spacecraft in the solar wind
might be able to alter the light falling on particles of the
wind to see how this affects their acceleration. (Explaining
the acceleration of the wind requires a source of momentum,
which conventional researchers have not yet found in the required
amounts with magnetic fields. Also, heavy ions recieve more
acceleration than light ions, and this might be explained by
a plasma redshift process interacting more strongly with
heavy ions - just as heavy atoms in a gas tend to slow light
Philip Helbig wrote:
> Presumably, you mean that this theory could have a cosmological
> redshift with no expansion.
Yes. If we find plasma redshift under our noses in the solar
corona, its reasonable to expect it in the inter-cluster medium.
There, I guess the inter-particle spacing is a metre or so, which
should be long enough to redshift both the main black-body light
and its absorption and emission lines by about the same amount.
I wouldn't expect much redshift of microwave emission lines, since
their coherence length is likely to be many metres. Nor would I
expect much plasma redshift of X-rays because they have such a
short wavelength that they experience the Universe as being very
> However, if the universe is static, you have to explain WHY it
> is static.
I disagree. Big-bang theorists are not required to explain why
there was a big-bang. A good day's work in science can be done by
disproving a theory, without offering any replacement to explain
the things which were supposedly explained by the defunct theory
I am not suggesting the Universe is necessarily absolutely static
- just that the cosmological redshift is not (or is mainly not)
Doppler / expansion. So I am suggesting that if there was a
"bang" then it was much longer ago than 13.7 billion years.
- Robin http://astroneu.com Melbourne Australia
>Philip Helbig wrote:
>> Presumably, you mean that this theory could have a cosmological
>> redshift with no expansion.
>Yes. If we find plasma redshift under our noses in the solar
>corona, its reasonable to expect it in the inter-cluster medium.
>There, I guess the inter-particle spacing is a metre or so, which
>should be long enough to redshift both the main black-body light
>and its absorption and emission lines by about the same amount.
>I wouldn't expect much redshift of microwave emission lines, since
>their coherence length is likely to be many metres. Nor would I
>expect much plasma redshift of X-rays because they have such a
>short wavelength that they experience the Universe as being very
The problem is that you find visible-light and radio redshifts which are
the same. Here's an example
And red shifted X-ray lines have also been observed
In my tentative theory, the similar or identical redshift of
visible light along with 21cm or X-rays can't be explained by
plasma redshift. So if the redshifts reported by these papers
are real then I figure the BBT is correct, since I can't
imagine anything other than Doppler creating them.
Still, there are so many problems with the BBT that I am not
inclined to abandon this project so easily. Maybe plasma
redshift or something similar will turn out to be part of the
final picture. I won't bug you or other people to consider it
as a cause of the cosmological redshift, since these papers
seem to rule that out.
I still think some process such as this needs to be considered
for the heating and acceleration of the solar corona and wind.
Something is depositing energy and momentum all the way out to
the outer planets and beyond. Something consistently raises
the temperature of the corona to a million degrees very close
to the Sun's surface, no matter what is happening with
large-scale magnetic fields. This is not explicable by
conventional theories. The momentum is always away from the
Sun, and what is continually streaming out of the Sun? Short
coherence length (~1 to 3 microns) wavefronts of light.
I think we should develop a really solid understanding of the
solar corona and wind before we can be confident that the
cosmological redshift is purely Doppler shift.
I have noted your critique at my site:
along with two critiques from Craig Markwardt:
Robin Whittle wrote:
> Thanks Jonathan for your critique and references. I can't
> fault these papers.
> In my tentative theory, the similar or identical redshift of
> visible light along with 21cm or X-rays can't be explained by
> plasma redshift. So if the redshifts reported by these papers
> are real then I figure the BBT is correct, since I can't
> imagine anything other than Doppler creating them.
I don't think that the reference Jonathan gave above
) is in any way conclusive here.
First of all, the redshift considered is very small (of the order of
z=0.01) and could, at least for one of the two cases considered in the
paper, even be due to a peculiar velocity of the absorbing galaxy.
Secondly, the lines considered are absorption lines. The light being
observed is actually that of the quasar lying behind the galaxy, and it
is anybody's guess what the coherency of this light in either
wavelength region is.
Thirdly, as indicated on my web page
http://www.plasmaphysics.org.uk/research/redshift.htm , both the
coherence length and/or the wavelength could be a limiting factor here
with regard to the redshift mechanism, and a wavelength of 21 cm is
presumably still significantly shorter than the average particle
distance in the intergalactic plasma. One would need data for a
wavelength of more than 1m in order to definitely notice any threshold
Another possibility is that in this case the redshift is actually not
caused by the random electric field of the intergalactic plasma, but by
a systematic electric field associated with the plasma halo that
surrounds all stars, galaxies and galaxy clusters. The point is that
this field has scale of the order of the objects involved, and the
wavelength/coherence length issue is thus not relevant here (as shown
on my page http://www.plasmaphysics.org.uk/research/lensing.htm , this
could at least explain the redshift of solar spectral lines, and may be
also the redshift and lensing associated with galaxies (although I have
not made a quantitative estimate yet for the latter case)).
X-ray redshifts should anyway not be affected by the field scale as
both the wavelength and coherence length are much shorter.
> I still think some process such as this needs to be considered
> for the heating and acceleration of the solar corona and wind.
> Something is depositing energy and momentum all the way out to
> the outer planets and beyond. Something consistently raises
> the temperature of the corona to a million degrees very close
> to the Sun's surface, no matter what is happening with
> large-scale magnetic fields. This is not explicable by
> conventional theories.
The temperature of the corona can simply be explained in terms of the
gravitational energy of the sun. What needs to be explained is the
lowered temperature of the photosphere, and I have suggested that
inelastic collisions of the original high energy protons with neutral
hydrogen in the photosphere is responsible for this. The small amount
of protons which does not suffer from inelastic collisions forms then
the corona and solar wind (see my page
Thomas Smid wrote:
> Secondly, the lines considered are absorption lines. The
> light being observed is actually that of the quasar lying
> behind the galaxy, and it is anybody's guess what the
> coherency of this light in either wavelength region is.
This raises a difficult and unconventional question about
light - but it they must be faced when considering a
mechanism which depends on "coherence length". In this
context, I use "coherence length" to refer to the thickness
(length in the direction of travel) of a planar wavefront
of a single impulse, if we consider that the total light
signal can be considered as being composed of many such
I think the best approach is to consider the total light
signal as the sum of a variety of signals. Short coherence-
length light can be thought of as many short wavefronts -
because one could generate a very short impulse with the
right shape to create the observed spectrum, and then create
something identical to the original light by launching many
such short impulse wavefronts with random phases. Then, we
could analyse the behaviour of the light by considering just
one such short impulse (unless there were non-linear
processes at work).
This model of light, emr etc. as being made of myriads of
short coherence length wavefronts, would apply to black body
light or broadband synchrotron light etc. from a quasar.
An emission line is clearly an additional signal, of longer
coherence length. The tricky question is how to think about
an absorption line. I think it is best to consider it as
a long coherence length signal (long wavefront like a sine
wave which rises and falls over hundreds or thousands of
sine wave cycles) which is generated by the narrow filter
(band reject in this instance) as the filter is stimulated
by each of the short coherence length input signals.
The sum of this signal and the input signals has the
spectrum we expect - the signal which constitutes the
absorption line is out of phase with the components of the
input signal only at those frequencies which are being
I think this is a more satisfactory approach than trying
to imagine the final filtered signal as consisting of
highly coherent components near the edges of the absorption
line. The original light had no such coherency, so how
could a band reject filter alter the light in neighbouring
frequencies so that they were more coherent?
On this basis, I expect the broad spectrum of black body,
or quasar, light to be redshifted in the plasma, as long as
the coherence length is less than the inter-particle
spacing, and the long coherence length absorption (or
emission) lines should not be redshifted much or at all.
I regret I can't describe this more mathematically.
> . . . both the coherence length and/or the wavelength
> could be a limiting factor here with regard to the
> redshift mechanism, and a wavelength of 21 cm is
> presumably still significantly shorter than the average
> particle distance in the intergalactic plasma.
I figure the width (in terms of frequency, for instance)
of these 21cm absorption lines is probably 1,000 to 100,000
times narrower than their frequency, so I figure the
coherence length of the signal which constitutes such a line
(emission or absorption) must have a coherence length 100 to
100,000 times 21 cm.
I don't understand the paragraph "Another possibility ...".
> The temperature of the corona can simply be explained
> in terms of the gravitational energy of the sun. What
> needs to be explained is the lowered temperature of the
> photosphere, . . .
Maybe there is an explanation for temperature rise as cold
particles fall towards the Sun, but that is not what is
Can you formulate your theory in terms of the experience of
particles at the photosphere? I see no problem in
explaining why the photosphere is at its current temperature.
Can you explain why a small proportion of these atoms, H2
molecules, He etc. atoms and ions are lifted up, against the
Sun's gravity, and heated to a million k and beyond, all the
while being lifted faster and faster? The lifting continues
out to Pluto and beyond, even though the temperature of the
particles drops considerably by then. Heavier ions are
accelerated faster than light ions and electrons:
My plasma redshift theory, such as it is, does explain this
once the inter-particle distance gets above the approximate
coherence length of the main body of sunlight - which I
figure is just a few microns, since the ~0.5 micron centre
of the emission is so broad.
If I had more mathematical chops I would do a Fourier
transform of the blackbody spectrum of the Sun to produce a
short impulse signal which has the same spectrum. If we
arbitrarily cut off the spectrum to ignore wavelengths
longer than 2 microns, we have still got more than 95% of
the Sun's energy. An impulse such as:
should reproduce the spectrum, and I guess it is only
2 or 3 microns long. The length of this impulse is
what I also call the "coherence length" and it could
be thought of as the depth of a planar wavefront.
According to http://www.seds.org/messier/more/virgo_gal.html , there
are galaxies which deviate from the 'Hubble flow' by almost 2000
km/sec. That's more than one of the galaxies considered in the paper
Jonathan referenced above.
> I don't understand the paragraph "Another possibility ...".
What I meant here is that the observed redshift of individual galaxies
might also to a certain degree be intrinsic due to a large scale steady
state electric field (plasma polarization field) being produced by a
plasma halo surrounding the galaxy (analogous to the effect I suggested
on my page http://www.plasmaphysics.org.uk/research/lensing.htm in
order to explain the redshift and bending of light by the sun). The
scale of this field would be the same as the size of the galaxy itself
and thus the coherency would not be an issue here (in contrast to the
random field of the intergalactic plasma which merely has a scale of 1m
You seem to assume that the overall width of a spectrum is always a
measure of the coherency of the radiation. This is in fact usually not
so. The continuum of the stars is not produced by a single wave-train
with a very short duration, but by long wave-trains which merely have
different frequencies: if a free electron recombines into a certain
atomic level, it produces a sharp line according to the difference of
the energy of the free electron and the atomic level, and it is only
the fact that the free electron energies are distributed continuously
over a rather wide range which lead to the apparent continuum. You
should consider the latter therefore rather as a blend of a large
number of sharp lines (which are actually even more coherent than
spectral lines arising from discrete transitions within the atom).
Essentially the same can be said when discrete atomic levels are
broadened by the plasma field fluctuations (Stark broadening) for
instance: also here the broadening does not imply a reduction of the
coherency, but you should consider it merely as a widening of the range
of frequencies possible for a transition. Neither of course does
Doppler broadening imply a change in coherency.
Although essentially the radiation in the apparent continuum is
therefore at least as coherent as line radiation, the point is that
during the emission the atoms undergo collisions with free electrons in
the plasma, and the associated phase jumps during the emission reduce,
according to my estimate, the coherence time to about 10^-12 sec in the
photosphere (for visible light) which translates into a coherence
length of about 10^-2 cm.
So you really can not tell anything about the coherency of a radiation
field just by looking at the width of the spectrum. The coherency of
the spectrum at a given frequency (as defined by the effective length
of the wavetrains at this frequency) is solely determined by the
physics in the emission region i.e. a) the intrinsic decay constants
for the atomic transitions and b) the collision frequencies.
Anyway, a coherence length of about 1 micron, as you suggested, would
mean that the coherence length is about the same as the wavelength. I
doubt actually that this kind of radiation would still be detectable.
> > The temperature of the corona can simply be explained
> > in terms of the gravitational energy of the sun. What
> > needs to be explained is the lowered temperature of the
> > photosphere, . . .
> Maybe there is an explanation for temperature rise as cold
> particles fall towards the Sun, but that is not what is
> Can you formulate your theory in terms of the experience of
> particles at the photosphere? I see no problem in
> explaining why the photosphere is at its current temperature.
> Can you explain why a small proportion of these atoms, H2
> molecules, He etc. atoms and ions are lifted up, against the
> Sun's gravity, and heated to a million k and beyond, all the
> while being lifted faster and faster? The lifting continues
> out to Pluto and beyond, even though the temperature of the
> particles drops considerably by then. Heavier ions are
> accelerated faster than light ions and electrons:
The photospheric temperature is irrelevant for the corona and the solar
wind. The latter arise from material that penetrates *through* the
photosphere from the region below (which has a temperature of 10^7 K
according to the gravitational energy of the sun). Note that this only
a very small amount of material, which, according to the arguments on
my page http://www.plasmaphysics.org.uk/research/sun.htm , is just a
fraction 10^-15 or less of what would escape without the presence of
the photosphere (which would actually potentially be a factor 1/e of
all the material, as this the fraction of particles with an energy
higher than the escape energy in a self-gravitating volume of gas).
You could probably compare the situation to the case of lava on the
earth's surface. You don't invoke fancy theories like magnetic
reconnection here either in order to explain the appearance of material
with a temperature of 1500 K in an environment having only a
temperature of 300 K. As everybody knows, the lava comes through cracks
from a region with a higher temperature below the earth's crust, and
this is essentially also what happens on the sun, with the only
difference that the photosphere is overall 'porous' to the high energy
particles from below.
There is an unarguable instance in the Perseus galaxy cluster.
The cluster has a redshift of about cz=5000 km/s. Partially
silhouetted in frontof the active central galaxy NGC 1275 is
a gas-rich galaxy (I can just about convince myself I see a
disorganized spiral pattern) complete with dust lanes, star
clusters, and cold gas. It appears in absorption against NGC 1275
in the optical (dust lanes), soft X-rays, and 21-cm H I absorption.
The demonstrably foreground object has cz=8000 km/s (frommemory, not
too exact). It's just possible for it to have picked up that
much peculiar velocity from a 3-sigma set of encounters with
other cluster members, but whatever, the cause, the peculiar
velocity component is there.
I can't imagine an explanation other than the two objects
moving towards each other at 0.01 the speed of light.
Thanks too for your extensive site!
In a message I wrote in the thread "Plasma Theory of
Galactic Redshifts and 'Gravitational Lensing' of Light" I
cite three papers by David G. Russell which argue for higher
redshift differences between members of the same cluster.
However, he argues these are not due, primarily, to velocity
differences but to some kind of intrinsic redshift mechanism.
Thanks Thomas for your response.
I can't imagine how a very large scale electric field could
develop between a galaxy and its surrounding plasma, or how
such a field could redshift light.
> You seem to assume that the overall width of a spectrum is
> always a measure of the coherency of the radiation.
Yes. I think of light like radio waves and signals in
audio and RF circuits. I do not think of it as "photons" -
I think the radiation is not quantized, but it seems that
its interaction with matter often, or always, is.
If I had electronic circuits small enough and fast enough I
could generate a perfect facsimile of the Sun's black-body
radiation by sending a randomly phased series of impulses to
a small antenna. The impulse would look something like I
sketched in my previous message. Each such impulse would
have the spectrum of the black body light. A single such
impulse of sufficient energy would deposit energy in lots of
"photons" distributed over the detector of a spectrograph
with the same statistics as the black body light from the
Sun. I argue that since I can make light which is
indistinguishable from that of the Sun (not counting
absorption lines etc.) out of a bunch of tiny impulses, and
that since we can predict many aspects of the behaviour of
the entire stream of impulses by thinking about just one
impulse, that it is valid to think of the light being made
up of such impulses. I know this may seem a little forced,
but it makes no sense to me what you suggest:
> The continuum of the stars is not produced by a single
> wave-train with a very short duration, but by long
> wave-trains which merely have different frequencies: if a
> free electron recombines into a certain atomic level, it
> produces a sharp line according to the difference of the
> energy of the free electron and the atomic level, and it
> is only the fact that the free electron energies are
> distributed continuously over a rather wide range which
> lead to the apparent continuum.
I don't believe that the maelstrom of atoms, ions and
electrons at the photosphere, or the vibrations in a hot
filament, can usefully be seen in terms of neat transitions
between clearly defined quantum energies of atoms. It looks
to me like a vast number of antennae all of which are
radiating in "random" ways, according to some common
Theoretically I think you could make black body light with
an infinitely (or near infinitely) large number of narrow
transmitters as you suggest - but this seems less physically
satisfying to me than the idea of lots of tiny impulses.
> . . . broadening does not imply a reduction of the
An eternal sine wave is infinitely coherent. Any random
or regular modulation of its amplitude or frequency produces
a broader spectrum which is inherently less coherent. I
don't think one has to consider how the signal was made -
just see it as an electrical signal in space and subject
it to spectrum analysis, electronically, with a prism or via
some other method such as a diffraction grating or an attempt
to detect it with a narrow filter such as an atom or
molecule which is ready to absorb this particular wavelength.
> . . . during the emission the atoms undergo collisions
> with free electrons in the plasma, and the associated
> phase jumps during the emission reduce, according to my
> estimate, the coherence time to about 10^-12 sec in the
> photosphere (for visible light) which translates into a
> coherence length of about 10^-2 cm.
> So you really can not tell anything about the coherency of
> a radiation field just by looking at the width of the
I completely disagree. I have already tried to explain why
I estimate the coherence length of black body sunlight is
just a few microns. I don't think it is necessary to
consider how the light is made. The spectrum alone tells us
how coherent it is.
If I get some random noise - white noise, which is
completely random values per sample (in a sampled digital
signal processing system) - this has no coherence at all.
Its coherence length is zero. If I filter it to give it
a spectrum identical to a black body spectrum, I introduce
some correlation between the value of one sample the values
of the samples which precede it. This gives it some
coherency - probably a few samples long, depending on
exactly how "coherence length" is defined.
If I then take this sample and pass it through a band-reject
filter, say one which only reduces frequencies in a range
of 0.0001 of the entire frequency range, as happens when
black body light passes through a gas or plasma which absorbs
narrow lines, then the result can be seen as the original
unfiltered signal plus a second, very narrow spectrum,
highly coherent, signal. That second signal nulls out the
energy which was in the original signal only in a very
narrow range of frequencies. A similar narrow (long
coherence length) signal is added if I use a narrow band
pass filter - its just that its phase constructively adds
to a narrow range of frequencies in the original.
> The photospheric temperature is irrelevant for the corona
> and the solar wind. The latter arise from material that
> penetrates *through* the photosphere from the region below
> (which has a temperature of 10^7 K according to the
> gravitational energy of the sun).
OK - I understand you see the photosphere as a kind of
barrier with a few particles passing through it, carrying
their thermal and kinetic energy. I had assumed you were
invoking your plasma redshift theory to account for the
heating and acceleration of the corona and wind.
I can't imagine how this penetration of the photosphere
could occur, and I can't see how any such process could
explain the rising temperature gradient, the thinning plasma
and the increasing velocity well into the corona. Nor do I
see how your theory could explain delivery of momentum to
ions etc. in the wind, way out past the Earth's orbit. I
understand they are still being accelerated all through the
distances we have so far been able to observe, such as with
the Pioneer spacecraft.
With volcanoes, we observe the lava getting cooler and
slowing down with gravity as it emerges. Completely the
opposite occurs with the solar corona and wind.
- Robin http://astroneu.com
The point is that electrons tend to escape from any plasma volume due
to the fact that a) they have a much higher velocity than ions of the
same energy (due to their much smaller mass) and b) they are
gravitationally practically unbound. Electrons will therefore diffuse
to larger distances or some will escape altogether until an electric
field (plasma polarization field) is set up such that further electrons
will be prevented from escaping (or strictly speaking until the field
results in a zero net electron current).
The redshift mechanism would essentially be the same as for the
intergalactic plasma i.e. the field would 'stretch' the light wave. The
point is that the galactic halo field would be a steady field with a
much larger scale than the random field of the intergalactic plasma,
and thus the coherence length or wavelength would not present any
> You wrote:
> > You seem to assume that the overall width of a spectrum is
> > always a measure of the coherency of the radiation.
> Yes. I think of light like radio waves and signals in
> audio and RF circuits. I do not think of it as "photons" -
> I think the radiation is not quantized, but it seems that
> its interaction with matter often, or always, is.
> An eternal sine wave is infinitely coherent. Any random
> or regular modulation of its amplitude or frequency produces
> a broader spectrum which is inherently less coherent. I
> don't think one has to consider how the signal was made -
> just see it as an electrical signal in space and subject
> it to spectrum analysis, electronically, with a prism or via
> some other method such as a diffraction grating or an attempt
> to detect it with a narrow filter such as an atom or
> molecule which is ready to absorb this particular wavelength.
I don't think is correct (not in this context anyway):
the Fourier theorem (which you are apparently applying here) assumes
actually that all the frequencies in the spectrum are waves which not
only extend from -infinity to +infinity in time, but also are all
locked in phase: I am sure you know for instance that the frequency
spectrum of a rectangular pulse of duration T is given by the
sinc-function sin(f*T/2)/(f*T/2) where f is the frequency. The
pulse is exactly reconstructed if you superpose waves (ranging
continuously in frequency from -infinity to +infinity) with this
amplitude, but this is obviously only possible if all the sub-waves
belonging to the individual frequencies f are locked in phase somehow.
If the phases of the waves are however randomly uncorrelated, they
could never produce the constructive and destructice interference
required to reconstitute the rectangular pulse.
The point here is that for all natural light sources the phases of the
individual waves *are* randomly uncorrelated as they originate from
statistically independent atomic emissions.
So the Fourier theorem can not be applied here to obtain the coherence
length of the signal from the shape of the spectrum. The coherence
length must be physically determined by the atomic decay times and/or
collision times that are relevant for the radiation produced.