CMBR and neutron stars

The CMBR appears to have a perfect blackbody emission curve, at
least from what is left after passing through intergalactic and
interstellar "stuff". Normal matter does not produce the kind of
emission curve that the CMBR produces (apparently).

Certain types of neutron stars also appear to have perfect
blackbody emission curves. I'm not sure how in-general-neutral
particles can emit thermal photons, but that is another lesson.

Black holes are expected to "start with" very dense cores, such
as neutron stars.

What is the possibility that the CMBR is not "hydrogen gas at
about 3000 K" but rather the emissions of the "matter structure"
that triggered this Universe?

David A. Smith

N:dlzc D:aol T:com (dlzc) wrote:
What is the possibility that the CMBR is not "hydrogen gas at
about 3000 K" but rather the emissions of the "matter structure"
that triggered this Universe?

In some sense it is, but not in the sense you mean. It's like asking whether
the light we see from the sun might really come from deep inside, rather
than from the photosphere. We may be able to figure out what's going on
inside the sun, but we can't *see* it. It's the same with the first 300,000
years after the big bang.

-- Ben

N:dlzc D:aol T:com (dlzc) wrote:
The CMBR appears to have a perfect blackbody emission curve, at
least from what is left after passing through intergalactic and
interstellar "stuff". Normal matter does not produce the kind of
emission curve that the CMBR produces (apparently).

Sure it does, as long as it is black. The feature of the CMBR that
radiation from the clumped matter of today does not reproduce is the
CMBR's near isotropy.


Certain types of neutron stars also appear to have perfect
blackbody emission curves. I'm not sure how in-general-neutral
particles can emit thermal photons, but that is another lesson.

Any black object will emit a black body spectrum. And virtually all
astronomical objects are very close to black (with some
absorbtion/emission lines added -- ignore them). That's why the black
body model is so useful.


What is the possibility that the CMBR is not "hydrogen gas at
about 3000 K" but rather the emissions of the "matter structure"
that triggered this Universe?

During the first ~300k years after the big bang the universe was filled
with dense ionized matter (not "hydrogen gas"). After the first few
seconds this was primarily bare protons and electrons in a very hot
charged plasma. Such a plasma is opaque to essentially all types of EM
radiation. So any EM radiation remnant from the big bang itself would
have been absorbed and re-emitted many times during this period, so what
we can see today is characteristic of the last time period of that
plasma (just before it combined into neutral hydrogen [plus small
admixtures of He and Li]).


Tom Roberts

In article mrDFe.148733$Qo.22449@fed1read01,
"N:dlzc D:aol T:com \(dlzc\)" N: dlzc1 D:cox writes:
The CMBR appears to have a perfect blackbody emission curve, at
least from what is left after passing through intergalactic and
interstellar "stuff".

In particular, the spectral shape follows a blackbody curve, and the
emissivity equals one. Some people with "alternative theories"
ignore the second property.

Normal matter does not produce the kind of
emission curve that the CMBR produces (apparently).

Why do you think this? You can buy a laboratory blackbody source,
and it will certainly be made of normal matter. What you cannot do
is produce a blackbody curve by simply superposing sources having a
range of temperatures.

Certain types of neutron stars also appear to have perfect
blackbody emission curves. I'm not sure how in-general-neutral
particles can emit thermal photons, but that is another lesson.

Presumably you mean the stellar surface, not the accretion disk. Do
you have a reference? I'm wondering how the two are separated,
though I don't think the result is surprising.

Black holes are expected to "start with" very dense cores, such
as neutron stars.

What makes you think this?

What is the possibility that the CMBR is not "hydrogen gas at
about 3000 K" but rather the emissions of the "matter structure"
that triggered this Universe?

I don't understand the question, but Tom Roberts appears to have
addressed part of it. As noted above, any alternate theory for the
CMBR needs to address its emissivity as well as its spectrum.

One disagreement I do have with Mr. Roberts (Message-ID:
) is where he writes:
virtually all astronomical objects are very close to black (with
some absorbtion/emission lines added -- ignore them).

At best this is true only for a loose definition of "very close," and
even then for only a narrow selection of objects. Stars, even
ignoring lines, have opacity that varies with wavelength. In effect,
one sees a different temperature at different wavelengths, although
in the visible and near infrared the range is not huge, and blackbody
emission may be a useful approximation for some purposes. (Flux
errors might be a few tens of percent, for example.) Such objects as
accretion disks and dust particles, though, are not even close to
being blackbodies.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)

Thanks to all responders, Ben Rudiak-Gould, Tom Roberts, Steve
Willner,

Dear Steve Willner:

"Steve Willner" wrote in message
...
In article mrDFe.148733$Qo.22449@fed1read01,
"N:dlzc D:aol T:com \(dlzc\)" N: dlzc1 D:cox
writes:
The CMBR appears to have a perfect blackbody emission
curve, at least from what is left after passing through
intergalactic and interstellar "stuff".

In particular, the spectral shape follows a blackbody curve,
and the emissivity equals one. Some people with
"alternative theories" ignore the second property.

Normal matter does not produce the kind of
emission curve that the CMBR produces (apparently).

Why do you think this? You can buy a laboratory
blackbody source, and it will certainly be made of
normal matter. What you cannot do is produce a
blackbody curve by simply superposing sources
having a range of temperatures.

The CMBR is presented as a (primarily) hydrogen plasma. No
plasma we have seen elsewhere, provides the blackbody curve the
CMBR does. The blackbody sources you purchase are
*approximately* blackbody at temperatures far from 3000 K.

Certain types of neutron stars also appear to
have perfect blackbody emission curves. I'm not
sure how in-general-neutral particles can emit thermal
photons, but that is another lesson.

Presumably you mean the stellar surface, not the
accretion disk. Do you have a reference? I'm wondering
how the two are separated, though I don't think the result
is surprising.

They call it the "atmosphere", even though it is "iron" and
likely denser than lead... ;)
URL:http://adsabs.harvard.edu/cgi-bin/np...ML&format=
QUOTE
.... of a 22.7 ks observation of XTE J1709-267 obtained with the
Chandra satellite when the source was in quiescence. We found
that the source has a soft quiescent spectrum which can be fit
well by an absorbed black body or neutron star atmosphere model.
END QUOTE

Black holes are expected to "start with" very dense cores,
such
as neutron stars.

What makes you think this?

A number of ".edu" websites. Do you have a better qualified
link?

What is the possibility that the CMBR is not "hydrogen
gas at about 3000 K" but rather the emissions of the
"matter structure" that triggered this Universe?

I don't understand the question, but Tom Roberts appears
to have addressed part of it. As noted above, any alternate
theory for the CMBR needs to address its emissivity as well
as its spectrum.

And I am believing that "hydrogen plamsa" doesn't do it, so am
"offering" something we have observed that *does* provide the
proper spectrum at elevated temperature.

One disagreement I do have with Mr. Roberts (Message-ID:
) is where he writes:
virtually all astronomical objects are very close to black
(with
some absorbtion/emission lines added -- ignore them).

At best this is true only for a loose definition of "very
close,"
and even then for only a narrow selection of objects. Stars,
even ignoring lines, have opacity that varies with wavelength.
In effect, one sees a different temperature at different
wavelengths, although in the visible and near infrared the
range is not huge, and blackbody emission may be a
useful approximation for some purposes. (Flux errors might
be a few tens of percent, for example.) Such objects as
accretion disks and dust particles, though, are not even
close to being blackbodies.

OK.

David A. Smith

Dear Ben Rudiak-Gould:

"Ben Rudiak-Gould" wrote in message
...
N:dlzc D:aol T:com (dlzc) wrote:
What is the possibility that the CMBR is not "hydrogen
gas at about 3000 K" but rather the emissions of the
"matter structure" that triggered this Universe?

In some sense it is, but not in the sense you mean. It's
like asking whether the light we see from the sun might
really come from deep inside, rather than from the
photosphere. We may be able to figure out what's going
on inside the sun, but we can't *see* it. It's the same
with the first 300,000 years after the big bang.

We *can* see through the photosphere, just not in visible
wavelengths. The CMBR does not have the blackbody emission
spectrum of "normal matter" at the temperature we attribute to
it. Hydrogen (mostly) doesn't work. It doesn't work in the Sun,
or in the near space around the Sun, where the plasma is at 3000
K.

Thanks for the response.

David A. Smith

Dear Tom Roberts:

"Tom Roberts" wrote in message
...
N:dlzc D:aol T:com (dlzc) wrote:

A defintion, since I seem to *suck* at this
CMBRM - the "stuff" that emitted what we call the CMBR

The CMBR appears to have a perfect blackbody emission
curve, at least from what is left after passing through
intergalactic and interstellar "stuff". Normal matter does
not produce the kind of emission curve that the CMBR
produces (apparently).

Sure it does, as long as it is black.

I find no reference that supports this claim, Tom. Especially
not at 3000 K. At/near room temperautre, sure.

The feature of the CMBR that radiation from the clumped matter
of today does not
reproduce is the CMBR's near isotropy.

OK.

Certain types of neutron stars also appear to have
perfect blackbody emission curves. I'm not sure
how in-general-neutral particles can emit thermal
photons, but that is another lesson.

Any black object will emit a black body spectrum.
And virtually all astronomical objects are very close
to black (with some absorbtion/emission lines added
-- ignore them). That's why the black body model is
so useful.

I have always imagined the thermal emissions of normal matter as
the typical material "emission bands", smeared by thermal
velocities (gamma factor from individual atomic motions).
Neutrons don't have emission bands. I suppose their
"atmospheres" do... iron.

What is the possibility that the CMBR is not "hydrogen
gas at about 3000 K" but rather the emissions of the
"matter structure" that triggered this Universe?

During the first ~300k years after the big bang the universe
was filled with dense ionized matter (not "hydrogen gas").
After the first few seconds this was primarily bare protons
and electrons in a very hot charged plasma. Such a
plasma is opaque to essentially all types of EM radiation.
So any EM radiation remnant from the big bang itself would have
been absorbed and re-emitted many times during this
period, so what we can see today is characteristic of the
last time period of that plasma (just before it combined into
neutral hydrogen [plus small admixtures of He and Li]).

Tom, I am given to understand that the CMBR was produced by an
opaque "medium" (CMBRM). I am further given to understand that
the CMBR shows an intensity vs. frequency curve that is NOT
reproducable by hydrogen at 3000 K "locally".

I understand what the "party line" is regarding extrapolation to
a time before the CMBRM, assuming the CMBRM was 3000 K hydrogen
plasma.

I'm not trying to be an Idiot, it just seems to come out that
way.

David A. Smith

N:dlzc D:aol T:com (dlzc) wrote:
Dear Tom Roberts:

"Tom Roberts" wrote in message
...

N:dlzc D:aol T:com (dlzc) wrote:

A defintion, since I seem to *suck* at this
CMBRM - the "stuff" that emitted what we call the CMBR

It was emitted in a plasma. Mostly hydrogen and helium nuclii with free
electrons interacting with them. The part that we see is from the region
where due to recombination and increasing mean free path for photons the
universe between us and the emitter became tranparent (essentially
mostly neutral hydrogen). The so called surface of last scattering.

The CMBR appears to have a perfect blackbody emission
curve, at least from what is left after passing through
intergalactic and interstellar "stuff". Normal matter does
not produce the kind of emission curve that the CMBR
produces (apparently).

Sure it does, as long as it is black.

I find no reference that supports this claim, Tom. Especially
not at 3000 K. At/near room temperautre, sure.

Fully ionised plasmas are to a very good approximation black body
emitters. Why do you think they are not? It only gets tricky when you
have high mixtures of plasma and neutral species with wavelength
dependent properties (like you get in real stars with convection cells,
cooler atmospheres and very hot but tenuous solar winds).

Certain types of neutron stars also appear to have
perfect blackbody emission curves. I'm not sure
how in-general-neutral particles can emit thermal
photons, but that is another lesson.

Any black object will emit a black body spectrum.
And virtually all astronomical objects are very close
to black (with some absorbtion/emission lines added
-- ignore them). That's why the black body model is
so useful.

I have always imagined the thermal emissions of normal matter as
the typical material "emission bands", smeared by thermal
velocities (gamma factor from individual atomic motions).
Neutrons don't have emission bands. I suppose their
"atmospheres" do... iron.

It is more likely that it is from free electrons in the plasma
interacting with positive ions. Acceleration of a charged particle
generates radiation.

In the case of neutron stars there is also a synchrotron component of
emission from charged particles interacting with an immensely strong
magnetic field embedded in a radiply spinning stellar remnant.

What is the possibility that the CMBR is not "hydrogen
gas at about 3000 K" but rather the emissions of the
"matter structure" that triggered this Universe?

During the first ~300k years after the big bang the universe
was filled with dense ionized matter (not "hydrogen gas").
After the first few seconds this was primarily bare protons
and electrons in a very hot charged plasma. Such a
plasma is opaque to essentially all types of EM radiation.
So any EM radiation remnant from the big bang itself would have
been absorbed and re-emitted many times during this
period, so what we can see today is characteristic of the
last time period of that plasma (just before it combined into
neutral hydrogen [plus small admixtures of He and Li]).

Tom, I am given to understand that the CMBR was produced by an
opaque "medium" (CMBRM). I am further given to understand that
the CMBR shows an intensity vs. frequency curve that is NOT
reproducable by hydrogen at 3000 K "locally".

We cannot make a hydrogen plasma locally at 3000K that has the necessary
optical depth to look convincingly like a cosomlogical 3000K plasma. I
think you need to provide references to the experiment where this was
attempted and it them might be possible to explain in terms that you
will understand.

I understand what the "party line" is regarding extrapolation to
a time before the CMBRM, assuming the CMBRM was 3000 K hydrogen
plasma.

I'm not trying to be an Idiot, it just seems to come out that
way.

ICP optical and mass spectrometry argon plasma sources look pretty much
like black body radiation, as does the intial phase of a nuclear
explostion. Energetic plasmas are not very common on earth.

Regards,
Martin Brown

N:dlzc D:aol T:com \(dlzc\):
The CMBR appears to have a perfect blackbody emission curve, at
least from what is left after passing through intergalactic and
interstellar "stuff". Normal matter does not produce the kind of
emission curve that the CMBR produces (apparently).

Well, it does when the spectrum is produced by free electrons
(or charges, in general) rather than by excitations of bound
charges, which produce a discrete spectrum.

Certain types of neutron stars also appear to have perfect
blackbody emission curves. I'm not sure how in-general-neutral
particles can emit thermal photons, but that is another lesson.

Recall that while neutrons are neutral, overall, they have
magnetic dipole moments and are bound states of charged quarks.
However, there is also more to a neutron star than just neutrons.

Black holes are expected to "start with" very dense cores, such
as neutron stars.

What is the possibility that the CMBR is not "hydrogen gas at
about 3000 K" but rather the emissions of the "matter structure"
that triggered this Universe?

Anything is possible if one can concoct a theory around it which
doesn't contradict observations. Unfortunately, that's very hard to
do. There should be evidence from neutrinos that could say more
about the universe prior to the period which produced the cosmic
background radiation, but unfortunately, neutrinos are not as
user freindly. Obtaining the equivalent neutrino spectum is not
yet technologically feasible. Our understanding of the universe
prior to the production of the background radiation comes mainly
from tying the electroweak and strong interactions to the temperatures
at which those forces should have appeared as distinct.

Dear Martin Brown:

"Martin Brown" wrote in
message ...
N:dlzc D:aol T:com (dlzc) wrote:
Dear Tom Roberts:

"Tom Roberts" wrote in message
...

N:dlzc D:aol T:com (dlzc) wrote:

A defintion, since I seem to *suck* at this
CMBRM - the "stuff" that emitted what we call the CMBR

It was emitted in a plasma. Mostly hydrogen and helium
nuclii with free electrons interacting with them. The part
that we see is from the region where due to
recombination and increasing mean free path for photons
the universe between us and the emitter became
tranparent (essentially mostly neutral hydrogen). The so
called surface of last scattering.

The CMBRM filed the early Universe. The CMBRM emitted blackbody
radiation. The radiation was not absorbed by the same
Universe-filling hydrogen because...

The CMBR appears to have a perfect blackbody emission
curve, at least from what is left after passing through
intergalactic and interstellar "stuff". Normal matter does
not produce the kind of emission curve that the CMBR
produces (apparently).

Sure it does, as long as it is black.

I find no reference that supports this claim, Tom. Especially
not at 3000 K. At/near room temperautre, sure.

Fully ionised plasmas are to a very good approximation
black body emitters. Why do you think they are not?

Absorption lines from our own Sun. Absorption lines from sources
in globular clusters. Emission lines from the same sources.
"Local" sources are not blackbody... except for some neutron
stars.

It only gets tricky when you have high mixtures of plasma and
neutral species with
wavelength dependent properties (like you get in real stars
with convection cells, cooler atmospheres and very hot
but tenuous solar winds).

But the CMBRM is presented as being exactly like the photosphere
of a star. Hot ionized hydrogen. How is it that the CMBRM
behaved differently than "local" hydrogen+helium *today*?

Certain types of neutron stars also appear to have
perfect blackbody emission curves. I'm not sure
how in-general-neutral particles can emit thermal
photons, but that is another lesson.

Any black object will emit a black body spectrum.
And virtually all astronomical objects are very close
to black (with some absorbtion/emission lines added
-- ignore them). That's why the black body model is
so useful.

I have always imagined the thermal emissions of
normal matter as the typical material "emission
bands", smeared by thermal velocities (gamma factor
from individual atomic motions). Neutrons don't have
emission bands. I suppose their "atmospheres" do...
iron.

It is more likely that it is from free electrons in the plasma
interacting with positive ions. Acceleration of a charged
particle generates radiation.

From Bilge's description, it sounds like Compton scattering from
free non-mutually-interacting charges fills the bill.

In the case of neutron stars there is also a synchrotron
component of emission from charged particles interacting
with an immensely strong magnetic field embedded in a
radiply spinning stellar remnant.

Yes, but these neutron-star candidates don't emit "pure"
blackbody radiation.

What is the possibility that the CMBR is not "hydrogen
gas at about 3000 K" but rather the emissions of the
"matter structure" that triggered this Universe?

During the first ~300k years after the big bang the universe
was filled with dense ionized matter (not "hydrogen gas").
After the first few seconds this was primarily bare protons
and electrons in a very hot charged plasma. Such a
plasma is opaque to essentially all types of EM radiation.
So any EM radiation remnant from the big bang itself would
have been absorbed and re-emitted many times during this
period, so what we can see today is characteristic of the
last time period of that plasma (just before it combined into
neutral hydrogen [plus small admixtures of He and Li]).

Tom, I am given to understand that the CMBR was produced
by an opaque "medium" (CMBRM). I am further given to
understand that the CMBR shows an intensity vs. frequency
curve that is NOT reproducable by hydrogen at 3000 K
"locally".

We cannot make a hydrogen plasma locally at 3000K that
has the necessary optical depth to look convincingly like a
cosomlogical 3000K plasma. I think you need to provide
references to the experiment where this was attempted and
it them might be possible to explain in terms that you will
understand.

Solar spectra. Spectra from globular clusters (and not their
interesting neutron stars). Optically dense.

I understand what the "party line" is regarding extrapolation
to a time before the CMBRM, assuming the CMBRM was 3000 K
hydrogen plasma.

I'm not trying to be an Idiot, it just seems to come out that
way.

ICP optical and mass spectrometry argon plasma sources
look pretty much like black body radiation, as does the intial
phase of a nuclear explostion. Energetic plasmas are not very
common on earth.

And opaque ones at that. Thanks.

I'll just have to fume on this for a while, I guess.

David A. Smith