"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:YyRPe.129306$E95.57191@fed1read01...
Dear George Dishman,

"George Dishman" wrote in message
...


... Last I
heard, there was no Dark Matter at the time of the CMBRM.
Where does this stand now?

Where did you hear that? I thought the WMAP results
supported dark matter.

I "heard that" here on sci.astro. Since I don't catch every bit of late
breaking news, and since I frequently get my memories rearranged, I was
asking you. So Dark Matter is evident in the CMBRM?

I just noticed this in another thread:


"Sam Wormley" wrote in message
news:67FPe.281485$x96.554@attbi_s72...

....
o The WMAP data give the most precise values for the density of
ordinary [baryonic] matter made of protons and neutrons and for the
dark matter: 0.4 and 2.5 yoctograms per cubic meter. These
correspond to omega_b = 0.0224 +/- 0.0009 and omega_m = 0.135 +/-
0.009.


However, you may also find this interesting:

http://lambda.gsfc.nasa.gov/product/...rams_table.pdf

Note the decoupling time is given as 118,000 years,
somewhat more than the 6300 I have been discussing.

These are not the same however, the first I think
is the time it took for the plasma to become neutral.
Recombination of one atom releases radiation which
tends to reionise other atoms so it takes a while
for the plasma to dilute and release the radiation.
That's different from the optical depth of the
plasma.

My memory also failed, z is 1089, not 1079, so the
calculated figure would drop to 6137 light years.
However, that show be modified as the fraction of
the gas which was ionised would have been decreasing
during the much longer period.

I hope that clears up a few points, I don't want to
mislead anyone.

George

Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox
wrote in message news:qoOPe.129290$E95.2723@fed1read01...
Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox
wrote in message news:5JPOe.124798$E95.60198@fed1read01...
Dear George Dishman:

.... The key p[o]int is that
no physics changes at the horizon and there is no
discontinuity.

http://www.astronomycafe.net/qadir/ask/a11125.html

This is the standard interpretation, yes. There are
alternatives to this interpretation, alternatives provided by
GR experts,

That is where you disagree with myself and both
Martin and Steve Carlip. I consider Steve to be
a "GR expert" having read his posts for many
years though he would no doubt disagree.

I don't disagree that he is more of a GR expert than I will ever
be.

Andrew
Hamilton is A professor lecturing on the subject
and is saying the same thing, there is only one
interpretation at the event horizon for a non-
rotating, non-charged black hole and it doesn't
have a singularity.

"There is one interpretation" is clearly false.

and I am attempting to test what I see is a perhaps
falsifiable part of their solutions. Yet I keep getting
this "but the standard interpretation is..."

No, what you keep getting is "There is only one
model provided by GR but it can be described in
a variety of coordinate schemes, some of which
don't work at the horizon.".

Including Schwarzchild.

What is annoying people who have been "experts"
in GR by any normal standard is that you refuse
to listen.

George, I have been listening. I have provided reasonable
citations from experts. I have logically countered those of my
points for which logic can be of any help. If you or anyone else
is annoyed that someone can ask a question that GR expert's
solutions indicate is a valid question, I am sorry. I was not
asking you to answer it. I am not sure now why I even bothered
you nice folks. Funny, I thought I was helping...

It is what happens at r=0 where there is a real
singularity and GR fails that is open to
interpretation.

This is your interpretation. Because the experts I cite (and
more) don't allow us to reach "the singularity at the center",
since the BH does eventually evaporate. So the strain you go
through to extend Newton into a black hole is your own fault.

Note also Andrew's quiz question 5:

http://casa.colorado.edu/~ajsh/quiz.html#quiz

The answer is he

http://casa.colorado.edu/~ajsh/schwp.html#metricinside

I think we can stop talking about Andrew and his pages. His
methods are not revealed, his wording is (apparently) sloppy,

"Answer to the quiz question 5: False."

That seems pretty unamibguous to me.

"The observer falls at c". Indirect methods referenced to
produce animations only list Schwarzchild, which are singular at
the event horizon, yet no method is "hinted" at to cover the
transition.

so I don't think I can learn anything further from his pages
as they stand.

"The Schwarzschild metric remains valid
inside the Schwarzschild radius. It is
fine to perform mathematical calculations
using the Schwarzschild metric."

Have you learnt that?

Yes, I have. To quote a famous person: "it is only a
mathematical model." And one of several.

This I think is where I disagree with Martin (which
worries me somewhat). I believe the answer is "to
an observer at infinity not moving relative to the
location of the black hole.". Have a look at the
freefall diagram:

http://casa.colorado.edu/~ajsh/schwp.html#freefall

Note that the green lines fall to the centre in
finite time and the time coordinate which is the
Y axis is the same regardless of whether the green
line is inside or outside. The orange lines show
light emitted by an infalling object. As the green
lines approach the horizon, the orange lines get
nearer to vertical and take ever longer to reach
the right-hand edge of the chart where a 'distant'
observer might hover by continually firing a rocket.

Once the green line (the freefalling object) crosses
the horizon though, the orange lines fall inwards,
the water is moving too fast for the duck (neat,
I just found Andrew used the same idea but with
canoes).

I have discussed path_average_speed with you in relation
to Shapiro time delay.

Note the the freefall lines are curved.

.... in 4D spacetime

The path
average over any section would be a chord between
two points.

As long as the "two points" are formed into /\s, and integrated
over the curved path, I agree.

The horizon is where the slope of the
line is c.

Yep.

Any usage of "falling at c" for any observer outside
the BH is meaningless,

"Falling at", implies to me the instantaneous speed
rather than an average. Outside the horizon it is
less than c, at the horizon is is equal to c while
inside it is greater. This is valid all the way to
the central singularity where the lines become
horizontal and speed becomes infinite.

Presumably for the frame of reference of an observer at infinity.
And when you factor in the "slower local clock" as you approach
the event horizon, falling at "the speed of light" *non-locally*,
isn't possible in *this* Universe.

even if you don't "buy" the "new internal Universe"
interpretation.

I'm not saying I am not prepared to consider it
but according to GR the entry to that universe
would be through the singularity at r=0 or at the
Cauchy horizon in the more general case I think.
This may be of interest, I ihaven't had a chance
to look through it myself yet though:

http://www.absoluteastronomy.com/enc...hy_horizon.htm

Thanks.

Because the path_average_speed for light at the horizon
now has a 0 value towards anyone outside the BH.

Not true, look at the freefall diagram again

http://casa.colorado.edu/~ajsh/stffbig_gif.html

You are talking about light this time rather than a
freefalling object so draw a chord between any two
points on a _yellow_ line. It has a finite non-zero
value. Infinitely far from the black hole the slope
of the line will be asymptotic to 45 degrees, the
speed of light. A path-average speed of zero would
require a chord to a yellow line which was vertical
on the diagram.

Compare with the light cones that GR produces to show the
severance of out and inner "spaces"...
http://www.phy.syr.edu/courses/modul...arzschild.html

Note that the speed of light radially out of the hole is zero at
the event horizon, because "radially out of the hole" is not
physically meaningful there.

So such claims would be non-sequitur.

So what use are the words, what meaning can they convey
where the context is not part of this Universe (except
though
total mass, total charge, total angular moementum)?

It is still part of this universe, the other universe
idea comes in after the matter passes the r=0 point.

No. I provided citations, George, but I cannot make you read
them. The other Universe starts at (some function of) r_S.

I read most of the pages. John Baez page was the first
of a series and I read the first three pages but his
maths is somewhat beyond my level. However, there seemed
to be only one paragraph that directly addressed this
point and subsequent pages were getting further from the
subject. I quoted that to you, here is the section in
whole (if you were refering to some other paragraph
please point me at it):

| To begin with, Lee Smolin, one of the originators of the loop
| representation of quantum gravity, has been spending the
| last year or so writing a book in a popular style, to be
| entitled "Life and Light," which tours the cosmos and makes
| some interesting speculations on "evolutionary cosmology."
| These speculations are based on 2 hypotheses.
|
| A. The formation of a black hole creates "baby universe,"
| the final singularity of the black hole tunnelling right on
| through to the initial "big bang" singularity of the new
| universe thanks to quantum effects. While this must
| undoubtedly seem outre to anyone unfamiliar with the
| sort of thing theoretical physicists amuse themselves with
| these days, in a recent review article by John Preskill on
| the information loss paradox for black holes, he reluctantly
| concluded that this was the *most conservative* solution
| of that famous problem!

and the relevant part again:

"the final singularity of the black hole tunnelling
right on through to the initial 'big bang' singularity
of the new universe"

Now I read "the final singularity" to mean r=0 where
there undoubtedly is a singularity. I guess you might
read it as meaning at the horizon, but at best it
doesn't resolve the question and IMHO it supports what
I and everyone else has been telling you.

And the second reference to Baez has another identical Universe
to ours being formed up just inside the event horizon.

If you can find something clear and unambiguous that
supports what you are saying about GR then I will
happily listen, I am here to learn, but so far you
have just been contradicting everything I have ever
read about the event horizon.

I have provided references. "Who" is contradicting you?

I think that's why Martin got the impression you are
taking a netkook attitude to this, though from past
discussions I'm somewhat surprised at your response.

You said the word: "annoyed". It is as if "this is a question
that must not be asked." And Martin appeared to be simply
dragging me around by my chain. I had more civil behavior from
Androcles, than I seemed to get from Martin.

See I was hoping this question would open new doors. And some
have opened, I've got the spectral data that I needed, and some
good things to consider when modelling:
- multiple models need to be considered,
- the matter infalling into a BH that is spewing X-ray jets, is
spewing it inside also,
- the CMBR will be a big player, but its contribution will be a
function of when the BH formed up,
- and the BH's own evaporation will provide a (perhaps)
non-trivial input.
Now I just need to guess how much of the companion is consumed,
and over what period of time, and I'll bet we have best guesses
available on the web also.

But I have now closed doors that didn't need to be closed.
Annoyance wasn't my intent.

Thanks.

David A. Smith

Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox
wrote in message news:YyRPe.129306$E95.57191@fed1read01...
Dear George Dishman,

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox
wrote in message news:XQROe.124809$E95.70204@fed1read01...
...
And how they could have NOT been aroud the early
Universe *at least once*, when it took ~300,000 years
to get to a size of 6300 ly. Maybe I'm being too
Newtonian about it...

No, I think it's more basic. The size in such a
universe would not be static. The radius first
increases then decreases. slice through it and
stack different slices at different times and
you get a shape like an american football
standing on one end. The path of a photon would
be a variable radius helix starting at the base
and winding round to the top. Looking down from
the top it turns through only 180 degrees total.

*That* went right over my head! I know the light cone, which
could remotely be called one end of a football (Amercian
football, yes?), and the expansion of the Universe could be
called the other end... but the spiral?

OK I'll try again. This must have been a post I saw
some years ago in s.p.r but I can't find it ATM.

ASCII is a problem my football looks like this:

^
/ \
( )
\ /
V

The big bang is at the bottom, the crunch is at
the top and now is somewhere below the middle
as space is still expanding. I'll show us as a
dot in the middle:

_____ crunch
^
/ \
( . ) ___ now
\ /
V _____ bang


A photon from the bang would pass us at
45 degrees to a horizontal on that diagram

_____ crunch
^
/ \
( / ) ___ photon
\ /
V _____ bang


Now extend that line in both directions always
keeping it at 45 degrees to a horizontal until
it reaches all the way from the bang to the
crunch. If you now look down from the top and
assuming the football is transparent, the line
is a curve that goes 180 degrees round the
football. If the maximum extent looking down
is a circle, then the path of the light I think
would be a smaller circle drawn between the
centre of the larger circle and the
circumference. Hence in this closed universe a
photon only gets half way round the universe
between bang and crunch, you couldn't see the
back of your head even with a big enough
telescope.

I will again emphasise this is an obsolete
model which has greater than critical density
and no cosmological constant.

OK. Thanks. I'll chew on that.

My figure of 6300 LY would suggest it was opaque at
372,700 years and transparent at 379,000 years. "In
an instant" doesn't seem inappropriate in cosmological
terms.

... but it does to a mechanical engineer! Is the
"thickness" being the same order of magnitude as the
global "quench" meaningful?

What do you mean by "global 'quench'"?

What was completed by "379,000 years". The plasma was
quenched to a normal matter state. If we were expanding
compressed air as an analogy, it the point at which water
vapor (as opposed to steam) would form.

OK, but then 6300 years is two order smaller
than that, not the same order of magnitude.

379,000 - 372,700 = 6,300

WMAP says recombination was about 380,000 years
after the bang, I subtracted 6300 to get 372,700.

... looks like the same order of magnitude.

378,000 is about two orders greater than 6300.

I misunderstood. OK. The "same magnitude" I saw was the
difference you intentionally formed, and the swapping of the
units "year" and "ly" just confused me.

The z of the CMBR can be thought of as produced
by motion of the source away from us but it can
also be considered as similar to gravitational
redshift or a stretching of the wavelength of
the photon while it was travelling through space
that was being stretched.

That sucked when Paul Lutus was feeding it to me.

It is a standard way of expressing it. I'm not
keen myself but I think the three descriptions
are effectively equivalent while appearing
different in the same sense as wave/particle
duality.

But it requires that the photon give up some of its
energy, yet retain the vector portion of its mometum
entirely intact. We don't know how to do that.

Both energy and momentum are proportional to
frequency, and both values are frame-dependent.

"We don't know how to do that."
Stretching is what we don't know how to do.

I thought you said we didn't know how to reduce the
energy without reducing the momentum which is true.

What we do see right here/now is gravitational time dilation,
which is sufficient also to describe the redshift of ancient
light.

Gravitational time dilation, Doppler shift and
stretching are all ways of describing the effect
that reduces the frequency. Reducing the frequency
affects both energy and momentum. You said "But it
requires that the photon give up some of its energy,
yet retain the vector portion of its mometum entirely
intact" which isn't correct.

George, when I went to school, we talked about the "direction"
and "magnitude" of a vector. I meant "direction portion of its
momentum", also called a "unit vector". I was less than clear,
as usual. We agree, move on.

QUOTE
Note that the redshift-velocity law is not the special
relativistic Doppler shift law
1+z = sqrt[(1+v/c)/(1-v/c)]
which only applies to special relativistic coordinates, not
to cosmological coordinates.
END QUOTE
neither a search for "kinetic" nor "motion" yielded as clear
a delineation as I'd like.

I think we have lost the thread on this, that
is just "the velocity" and doesn't draw any
distinctions.

It does, George. It delineates between velocity in Minkowski
spacetime, and expansion velocity.

No, the formula just has "v", the comment is again about
the choice of coordinates in which the formula is valid,
not breaking down the speed into components.

And the point is moot, since it wasn't as clearly phrased on
his pages as I "remembered".

Agreed, let's drop it.

OK.

I provided three links that indicate that it isn't "new
physics",
but a prediction of GR, quantum mechanics, or some
combination thereof. You may continue to disagree.

I just think you are looking at those pages with
a preconceived notion and are seeing what you
expect. I respect Steve Carlip's knowledge on GR
so I'll read what he says with great interest.

You indicated that you felt the same way about John Baez.
Two of the citations I provided were his, and the third was
Chris Hillman. Steve Carlip is also a very smart cookie.

Indeed but I couldn't find anything on any of
the pages that even hinted there was a physical
singularity at the event horizon, I am well aware
some coordinate system have problems but that is
not what we are arguing about.

George, what I don't get is why there must be a "physical
singularity" at the event horizon, for an internal Universe to
have formed. Physical has a pretty good meaning in Physics, and
we cannot measure anything starting at the event horizon and
including the "inside". What is fundamentally physical about
something you can never get a reading on?

Consider a young Universe, some 6300 ly "across", with
mass sufficient to achieve a "curvature coefficient" of
1079
(compared to today).

Lots of confusion there, the optical thickness
of the period of recombination was 6300 ly but
that happened at 380,000 years so the part of
the universe which is _currently_ observable
might have been 760,000 LY across and the
whole universe would have been billions of
light years across or perhaps infinite.

The plasma would be too thick to fill 760,000 ly,

I have no idea what that means!

and still generate the spectrum.

Or that!

It is based on the words you provided, which came from your
understanding of the topic when you said it. So maybe a
timeline will reveal my confusion:
BB - 366,000 - 372,300 - 379,000 - 14 Gy
... you say the CMBRM is 6300 ly thick, so I assumed 366,000
is the start of it (or the beginning of the end).

No, WMAP said it ocurred around 380,000 years and
it's about 6300 years thick from the calculations
we did before. The numbers aren't that exact of
course. However, I still don't understand. Imagine
the universe was a billion light years in every
direction. At 372,300 years it was all filled with
plasma that was sufficiently hot and dense to be
fairly opaque. 6300 years later it had thinned to
the point that it was mostly transparent. What do
you mean by "The plasma would be too thick to fill
760,000 ly"

I misunderstood the significance of the 6300 years. It is from
full opacity, to fully transparent. I thought this "6300ly" (a
distance) was the size of the Universe when the self-exciting
plasma decoupled. In other words, the Universe became "just a
little too large" for light to make it all the way around.

The spectrum depends on the temperature only, why
would the thickness prevent it being generated?

See immediately above.

The universe appears to be flat and would have
been then too. The figure of 1079 is the redshift
compared to today, not the curvature.

An indication of the curvature of the Universe that
emitted the light, vs. the Universe that detected it.

Again your words mean nothing to me. I believe z
is a measure of the angle between two normals to
a surface that has curvature between them, but I
also suspect that's too simplistic. However, I
don't see how you could compute the angle between
two points on curved surfaces in different
universes. How do you calculate across the
discontinuity?

It is continuous between them, isn;t it?

You have been saying there is a singularity between
them.

By the definition of singularity, there is. What is continuous
across the horizon is conservation of momenergy, conservation of
charge, Pauli exclusion, and perhaps more that I am not aware of.

If there isn't, they are parts of the same
universe. In terms of black holes, I thought we
agreed that the universes were separated by a
singularity but I say it is at r=0 while you say it
is at the event horizon. Either way you couldn't
calculate across it.

OK.

Sufficient to produce a redshift many orders of magnitude
greater than our Sun does, and by similar means. Last I
heard, there was no Dark Matter at the time of the CMBRM.
Where does this stand now?

Where did you hear that? I thought the WMAP results
supported dark matter.

I "heard that" here on sci.astro. Since I don't catch every
bit of late breaking news,

Me too which is why I am curious.

Mine is likely 4 years old, just about as long as I have been
"lurking".

and since I frequently get my memories rearranged, I was
asking
you. So Dark Matter is evident in the CMBRM?

I haven't seen anything on the subject, one way or the
other in the group. I thought the results of WMAP for
the angular power spectrum were consistent with the
fraction of dark matter found by other means but I
haven't checked the site yet and my memory is poor too.

OK. Another thread, another day.

For the CMBR, use this link

http://lambda.gsfc.nasa.gov/product/...prod_table.cfm

Yes. This would be good (as a start) for a free BH, or
one near our position in a "largely spiral" galaxy.

I intended that as a good start for the CMBR after
the removal of all stars. You need individual stellar
spectra separately. A free BH has no spectrum since
it is black !

The detector of a satellite can behave like a "differential
area" on an event horizon.

Again I have no idea what you mean. If we point a
satellite at a black hole, we don't see the hole,
only the universe behind distorted a bit.

Sigh...
George, I am going to use the recorded spectra, as
detected by "detectors", and infer from that via the
magic of integration, what the EH of a black hole
would ingest over its surface, over its lifetime. I thought I
said this more than once.

OK, maybe I misread you, I thought you were trying
to get satellite readings of the spectrum of an event
horizon itself.

It is the big red nose, orange wig, and big floppy shoes I
normally wear... ;)

You believe that the images will come in spectrally,
I do not.

That would be inside, we are outside all the black
holes we can use for a reference.

This is what you are comfortable in believing, yes George.

No, you misunderstand, I said we are outside the event
horizon of Cyg X1 and all the other black holes in our
universe which you might look at to get a spectrum to
do your calculations.

And do you not feel that what light is "sprayed out", also falls
back in? Or it expected to be like a laser, and only "heat" is
not directed outwards? I guess I'll do my own search...

I have seen "non-beginner" solutions to GR that indicate that
perhaps our Big Bang is the inside of an event horizon of a
black hole that contains our Universe. I propose to test this
by the above mentioned integration.

Indeed.

These may be of more use

http://www.astr.ua.edu/keel/agn/

In particular

http://www.astr.ua.edu/keel/agn/spectra.html

http://heasarc.gsfc.nasa.gov/docs/ob...n/agntext.html

http://en.wikipedia.org/wiki/Active_Galactic_Nuclei

Here is a problem in modelling. Would you say that the
percentage of active galactic nucleii vs. non-active (Milky
Way and Andromeda) would be and indication that this
behavior might be periodic. In other words, my
black-hole-in-galactic-center model should be sometimes
active, and sometimes not, roughly like the percentage
above?

That depends on the type, our [central black hole] will flare
when a star falls in and be quiescent otherwise. In the early
universe I think they tend to be bright steadily. I'm not too
familiar with this though.

I'll do some research, and state my sources (and conclusions) so
that those that know better (which are many here) can do it right
(or ignore it).

David A. Smith

Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox
wrote in message news:YyRPe.129306$E95.57191@fed1read01...
Dear George Dishman,

"George Dishman" wrote in message
...


... Last I
heard, there was no Dark Matter at the time of the CMBRM.
Where does this stand now?

Where did you hear that? I thought the WMAP results
supported dark matter.

I "heard that" here on sci.astro. Since I don't catch every
bit of late breaking news, and since I frequently get my
memories rearranged, I was asking you. So Dark Matter is
evident in the CMBRM?

I just noticed this in another thread:


"Sam Wormley" wrote in message
news:67FPe.281485$x96.554@attbi_s72...

...
o The WMAP data give the most precise values for the density
of
ordinary [baryonic] matter made of protons and neutrons
and for the
dark matter: 0.4 and 2.5 yoctograms per cubic meter. These
correspond to omega_b = 0.0224 +/- 0.0009 and omega_m =
0.135 +/-
0.009.


However, you may also find this interesting:

http://lambda.gsfc.nasa.gov/product/...rams_table.pdf

Note the decoupling time is given as 118,000 years,
somewhat more than the 6300 I have been discussing.

These are not the same however, the first I think
is the time it took for the plasma to become neutral.
Recombination of one atom releases radiation which
tends to reionise other atoms so it takes a while
for the plasma to dilute and release the radiation.
That's different from the optical depth of the
plasma.

My memory also failed, z is 1089, not 1079, so the
calculated figure would drop to 6137 light years.
However, that show be modified as the fraction of
the gas which was ionised would have been decreasing
during the much longer period.

I hope that clears up a few points, I don't want to
mislead anyone.

You have gone out of the way not to. I hope I have never given
the impression that you hadn't.

Is the 6137 ly a "maximum" or "average" path length? Just a
couple of search terms, if you don't mind, so that I know what
the physical model is...

David A. Smith

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:9O%Pe.129977$E95.125942@fed1read01...
Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:YyRPe.129306$E95.57191@fed1read01...
Dear George Dishman,

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:XQROe.124809$E95.70204@fed1read01...
...




The z of the CMBR can be thought of as produced
by motion of the source away from us but it can
also be considered as similar to gravitational
redshift or a stretching of the wavelength of
the photon while it was travelling through space
that was being stretched.
....
But it requires that the photon give up some of its
energy, yet retain the vector portion of its mometum
entirely intact. We don't know how to do that.
....
George, when I went to school, we talked about the "direction" and
"magnitude" of a vector. I meant "direction portion of its momentum",
also called a "unit vector". I was less than clear, as usual. We agree,
move on.

OK, if yuou had said "maintain its direction I would
have followed. The expansion of space is isotropic
hence stretching does not affect the direction of
the photon. Is that a more appropriate answer?

... I couldn't find anything on any of
the pages that even hinted there was a physical
singularity at the event horizon, I am well aware
some coordinate system have problems but that is
not what we are arguing about.

George, what I don't get is why there must be a "physical singularity" at
the event horizon, for an internal Universe to have formed. Physical has
a pretty good meaning in Physics, and we cannot measure anything starting
at the event horizon and including the "inside". What is fundamentally
physical about something you can never get a reading on?

An observer at great istance cannot get information
from inside the horizon. However the reverse is not
true, As Andrews simulations show, the infalling
observer can still see objects outside.

Now also consider three people roped together falling
in with the rope stretched by the tidal forces (it is
oriented radially). At some instant, the central person
reaches a location which is exactly on the horizon as
determined by an observer far outside. Of course that
observer can no longer see much. The person nearest
the hole is already within the horizon while the third
person is still outside and can wave to the distant
observer.

At that point, I believe the three people can still
communicate both ways, but by the time the third person
hears anything from the first, he too will have fallen
too far to relay the information to the distant observer.

The event horizon no more creates a ne universe than
a one-way mirror and in particular all the laws of
physics apply locally, i.e. between the three victims.
Of course they don't have long to check this but that's
another matter.

That's why I don't consider this a new universe. The
page you cited shows the inside of the cylinder as being
part of this with spacetime being continuous over the
horizon, what isn't shown is where the observer goes
after he hits the singularity. That isn't "in" this
diagram, the suggestion is it might be another universe.

No, WMAP said it ocurred around 380,000 years and
it's about 6300 years thick from the calculations
we did before. The numbers aren't that exact of
course. However, I still don't understand. Imagine
the universe was a billion light years in every
direction. At 372,300 years it was all filled with
plasma that was sufficiently hot and dense to be
fairly opaque. 6300 years later it had thinned to
the point that it was mostly transparent. What do
you mean by "The plasma would be too thick to fill
760,000 ly"

I misunderstood the significance of the 6300 years. It is from full
opacity, to fully transparent.

Well it is really the length over which the
visibility falls by e^-1. It's easiest to think
in reverse about how far light would penetrate
into the plasma. The probability of a photon
being absorbed depends on the distance so the
number that haven't been absorbed falls
exponentially. That's what the calculation
with the cross section provides. The time for
the material to recombine from transparent to
opaque is much longer as I just discovered,
see my other post on the WMAP results. Overall
we will se a combination of the two effects but
you now understand what I was talking about.

I thought this "6300ly" (a distance) was the size of the Universe when the
self-exciting plasma decoupled. In other words, the Universe became "just
a little too large" for light to make it all the way around.

Ah, that explains it. No, the universe was
probably infinite at all times. Your thinking
Newtonian here.

The universe appears to be flat and would have
been then too. The figure of 1079 is the redshift
compared to today, not the curvature.

An indication of the curvature of the Universe that
emitted the light, vs. the Universe that detected it.

Again your words mean nothing to me. I believe z
is a measure of the angle between two normals to
a surface that has curvature between them, but I
also suspect that's too simplistic. However, I
don't see how you could compute the angle between
two points on curved surfaces in different
universes. How do you calculate across the
discontinuity?

It is continuous between them, isn;t it?

You have been saying there is a singularity between
them.

By the definition of singularity, there is. What is continuous across the
horizon is conservation of momenergy, conservation of charge, Pauli
exclusion, and perhaps more that I am not aware of.

Spacetime is continuous over the horizon as are
all the laws of physics as viewed by an infalling
observer. Schwarzchild coordinates try to use a
stationary observer which cannot happen, that's
why they fail.

...Last I
heard, there was no Dark Matter at the time of the CMBRM.
Where does this stand now?
....
I haven't seen anything on the subject, one way or the
other in the group. I thought the results of WMAP for
the angular power spectrum were consistent with the
fraction of dark matter found by other means but I
haven't checked the site yet and my memory is poor too.

OK. Another thread, another day.

See my other post. (You just posted a reply
to it, I'll read that next.)

For the CMBR, use this link

http://lambda.gsfc.nasa.gov/product/...prod_table.cfm

Yes. This would be good (as a start) for a free BH, or
^^^^^^^
one near our position in a "largely spiral" galaxy.

I intended that as a good start for the CMBR after
the removal of all stars. You need individual stellar
spectra separately. A free BH has no spectrum since
^^^^^^^
it is black !

The detector of a satellite can behave like a "differential area" on
an event horizon.

Again I have no idea what you mean. If we point a
satellite at a black hole, we don't see the hole,
only the universe behind distorted a bit.

Sigh...
George, I am going to use the recorded spectra, as
detected by "detectors", and infer from that via the
magic of integration, what the EH of a black hole
would ingest over its surface, over its lifetime. I thought I said this
more than once.

OK, maybe I misread you, I thought you were trying
to get satellite readings of the spectrum of an event
horizon itself.

It is the big red nose, orange wig, and big floppy shoes I normally
wear... ;)

Those and your repeated use of "free BH" ;-)

If you want the spectrum of the acretion disk
of an active BH, that's a different matter
entirely.

You believe that the images will come in spectrally,
I do not.

That would be inside, we are outside all the black
holes we can use for a reference.

This is what you are comfortable in believing, yes George.

No, you misunderstand, I said we are outside the event
horizon of Cyg X1 and all the other black holes in our
universe which you might look at to get a spectrum to
do your calculations.

And do you not feel that what light is "sprayed out", also falls back in?
Or it expected to be like a laser, and only "heat" is not directed
outwards? I guess I'll do my own search...

What does that have to do with accusing me
of being "comfortable in believing" we are
outside the event horizon of all the black
holes we can observe? There's a bit of
talking past each other going on here (or
you're pulling my leg vbg!).

George

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Dear George Dishman:

"George Dishman" wrote in message
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
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Dear George Dishman,

"George Dishman" wrote in message
...


... Last I
heard, there was no Dark Matter at the time of the CMBRM.
Where does this stand now?

Where did you hear that? I thought the WMAP results
supported dark matter.

I "heard that" here on sci.astro. Since I don't catch every bit of late
breaking news, and since I frequently get my memories rearranged, I was
asking you. So Dark Matter is evident in the CMBRM?

I just noticed this in another thread:


"Sam Wormley" wrote in message
news:67FPe.281485$x96.554@attbi_s72...

...
o The WMAP data give the most precise values for the density of
ordinary [baryonic] matter made of protons and neutrons and for the
dark matter: 0.4 and 2.5 yoctograms per cubic meter. These
correspond to omega_b = 0.0224 +/- 0.0009 and omega_m = 0.135 +/-
0.009.


However, you may also find this interesting:

http://lambda.gsfc.nasa.gov/product/...rams_table.pdf

Note the decoupling time is given as 118,000 years,
somewhat more than the 6300 I have been discussing.

These are not the same however, the first I think
is the time it took for the plasma to become neutral.
Recombination of one atom releases radiation which
tends to reionise other atoms so it takes a while
for the plasma to dilute and release the radiation.
That's different from the optical depth of the
plasma.

My memory also failed, z is 1089, not 1079, so the
calculated figure would drop to 6137 light years.
However, that show be modified as the fraction of
the gas which was ionised would have been decreasing
during the much longer period.

I hope that clears up a few points, I don't want to
mislead anyone.

You have gone out of the way not to. I hope I have never given the
impression that you hadn't.

Is the 6137 ly a "maximum" or "average" path length? Just a couple of
search terms, if you don't mind, so that I know what the physical model
is...

The particles in the plasma are randomly scattered
and have a cross-section. If you work out how far
into the plasma an arbitrary line will go before
hitting a particle (i.e. working back along the
path of a photon to see where it originated) the
distribution for lots of photons will fall
exponentially with distance. It is the coefficient
in that function so about 63% come from the first
6137 light years, 63% of the remainder from the next
6137 and so on. However, that calculation assumed
the plasma was fully ionised. The fraction that was
ionised fell over a much longer period, about 118,000
years if I understand the term "decoupling time" on
the WMAP page. If so, it would be necessary to find
an equation for the reduction in that fraction, and
also note the density would change significantly over
that time, and then apply the previous analysis too
and integrate. It all becomes much more complex. My
only warning over that is that the end result might
be what WMAP means by "decoupling time" rather than
the ionisation per se. That's something I need to
research too.

George

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"George Dishman" wrote in message
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Dear George Dishman:

"George Dishman" wrote in message
...


Andrew
Hamilton is A professor lecturing on the subject
and is saying the same thing, there is only one
interpretation at the event horizon for a non-
rotating, non-charged black hole and it doesn't
have a singularity.

"There is one interpretation" is clearly false.

OK, other than you, I have only seen one
interpretation from all the experts I have read
including the pages you cited though I accept
you read them differently.

and I am attempting to test what I see is a perhaps
falsifiable part of their solutions. Yet I keep getting
this "but the standard interpretation is..."

No, what you keep getting is "There is only one
model provided by GR but it can be described in
a variety of coordinate schemes, some of which
don't work at the horizon.".

Including Schwarzchild.

Yes. However, as long as you know the manner in
which they don't work, you can correct that.

What is annoying people who have been "experts"
in GR by any normal standard is that you refuse
to listen.

George, I have been listening. I have provided reasonable citations from
experts. I have logically countered those of my points for which logic
can be of any help.

You countered your own points - must be a typo?

If you or anyone else is annoyed that someone can ask a question that GR
expert's solutions indicate is a valid question, I am sorry. I was not
asking you to answer it. I am not sure now why I even bothered you nice
folks. Funny, I thought I was helping...

I think Martin got a bit annoyed when he talked
of your attitude being a bit netkookish, apologies
to all if I misread that, but it wasn't because
you asked the question but that you seemed to
discount the answer when it wasn't what you wanted.

It is what happens at r=0 where there is a real
singularity and GR fails that is open to
interpretation.

This is your interpretation. Because the experts I cite (and more) don't
allow us to reach "the singularity at the center", since the BH does
eventually evaporate.

Look at the page you cite later

http://www.phy.syr.edu/courses/modul...arzschild.html

The bottom diagram shows the "foolish observer" reaching
the central singularity in a short time, milliseconds to
hours for real black holes. Evaporation takes billions
of years.

So the strain you go through to extend Newton into a black hole is your
own fault.

None of this is Newton, pure GR.

Note also Andrew's quiz question 5:

http://casa.colorado.edu/~ajsh/quiz.html#quiz

The answer is he

http://casa.colorado.edu/~ajsh/schwp.html#metricinside

I think we can stop talking about Andrew and his pages. His methods are
not revealed, his wording is (apparently) sloppy,

"Answer to the quiz question 5: False."

That seems pretty unamibguous to me.

"The observer falls at c".

Correct and accurate for a distant observer. Also
clearly shown on the page you cited as the otward
lightcone must be at c relative to the infalling
observer and it is parallel to the horizon.

Indirect methods referenced to produce animations only list Schwarzchild,
which are singular at the event horizon, yet no method is "hinted" at to
cover the transition.

If the coordinates flip, just use the right one
inside. I don't know the details but I guess most
books on GR will tell you.

Any usage of "falling at c" for any observer outside
the BH is meaningless,

"Falling at", implies to me the instantaneous speed
rather than an average. Outside the horizon it is
less than c, at the horizon is is equal to c while
inside it is greater. This is valid all the way to
the central singularity where the lines become
horizontal and speed becomes infinite.

Presumably for the frame of reference of an observer at infinity.

I believe so.

And when you factor in the "slower local clock" as you approach the event
horizon, falling at "the speed of light" *non-locally*, isn't possible in
*this* Universe.

That doesn't make sense to me. Look at the page you
cited again, the slope of the infalling "foolish
observer" is that of "falling at c" as he crosses
the event horizon. His (local) clock is ticking off
the time in equal steps along his worldline. The
reason we see his clock slowing is that the outgoing
lightlike lines take progressively longer to reach
the left edge of the graphic where a static observer
might be located. Accroding to that observer, the
infalling observer is moving at c even though he
appears slowed when seen through a telescope. That
is just an optical illusion.

Because the path_average_speed for light at the horizon
now has a 0 value towards anyone outside the BH.

Not true, look at the freefall diagram again

http://casa.colorado.edu/~ajsh/stffbig_gif.html

You are talking about light this time rather than a
freefalling object so draw a chord between any two
points on a _yellow_ line. It has a finite non-zero
value. Infinitely far from the black hole the slope
of the line will be asymptotic to 45 degrees, the
speed of light. A path-average speed of zero would
require a chord to a yellow line which was vertical
on the diagram.

Compare with the light cones that GR produces to show the severance of out
and inner "spaces"...
http://www.phy.syr.edu/courses/modul...arzschild.html

Note that the speed of light radially out of the hole is zero at the event
horizon, because "radially out of the hole" is not physically meaningful
there.

I am an idiot. You said "towards anyone outside
the BH." but I considered infalling light. My
mistake, you are right on that one. It only stops
us viewing what happens though, it doesn't stop
it happening.

Now I read "the final singularity" to mean r=0 where
there undoubtedly is a singularity. I guess you might
read it as meaning at the horizon, but at best it
doesn't resolve the question and IMHO it supports what
I and everyone else has been telling you.

And the second reference to Baez has another identical Universe to ours
being formed up just inside the event horizon.

You mean this page?

http://math.ucr.edu/home/baez/PUB/generichole

Again, he shows the paths of test particles falling
through the event horizon and falling for some time
before reaching either "a -spacelike- curvature
singularity" or a "weak null Cauchy horizon
singularity", whatever that means. Either way there
is nothing unusual about the region inside the
horizon prior to hitting the singularities. In fact
the text also says "just as for the Schwarzschild
solution, but no wormhole or multiple 'external
universe' sheets." so you have a diagram with a line
in the middle separating two regions and "no external
universes" shown. Clearly all of that diagram refers
to our universe. This is perhaps why I couldn't
fathom why you cited it.

If you can find something clear and unambiguous that
supports what you are saying about GR then I will
happily listen, I am here to learn, but so far you
have just been contradicting everything I have ever
read about the event horizon.

I have provided references. "Who" is contradicting you?

For example your statement that "Baez has another
identical Universe to ours being formed up just
inside the event horizon." seems to contradict his
statement that the diagram doesn't show any
"external universe sheets".

I think that's why Martin got the impression you are
taking a netkook attitude to this, though from past
discussions I'm somewhat surprised at your response.

You said the word: "annoyed". It is as if "this is a question that must
not be asked."

No, I think it was "why ask if you are going to
ignore any answer that conflicts with what you
have already decided." You asked about the
influence on the spectrum of the singularity
at the event horizon and the answer you got
was that there is no effect because the event
horizon isn't a physical singularity, just a
glitch in the maths.

And Martin appeared to be simply dragging me around by my chain. I had
more civil behavior from Androcles, than I seemed to get from Martin.

See I was hoping this question would open new doors. And some have
opened, I've got the spectral data that I needed, and some good things to
consider when modelling:

Well perhaps another door has opened too, the
event horizon isn't a singularity as you thought
and perhaps that knowledge will lead you to an
improved understanding of GR and new models. Be
positive, it is up to you what you make of it.

- multiple models need to be considered,
- the matter infalling into a BH that is spewing X-ray jets, is spewing it
inside also,
- the CMBR will be a big player, but its contribution will be a function
of when the BH formed up,
- and the BH's own evaporation will provide a (perhaps) non-trivial input.
Now I just need to guess how much of the companion is consumed, and over
what period of time, and I'll bet we have best guesses available on the
web also.

But I have now closed doors that didn't need to be closed. Annoyance
wasn't my intent.

You can always take someone out of your killfile
as easily as you plonked them in ;-)

George

Dear George Dishman:

"George Dishman" wrote in message
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wrote in message
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The z of the CMBR can be thought of as produced
by motion of the source away from us but it can
also be considered as similar to gravitational
redshift or a stretching of the wavelength of
the photon while it was travelling through space
that was being stretched.
...
But it requires that the photon give up some of its
energy, yet retain the vector portion of its mometum
entirely intact. We don't know how to do that.
...
George, when I went to school, we talked about the
"direction" and "magnitude" of a vector. I meant
"direction portion of its momentum", also called a
"unit vector". I was less than clear, as usual. We agree,
move on.

OK, if yuou had said "maintain its direction I would
have followed. The expansion of space is isotropic
hence stretching does not affect the direction of
the photon. Is that a more appropriate answer?

Yes. Had I used "unit vector", it would have been clear also,
but toting that around in context is a little unwieldy.

... I couldn't find anything on any of
the pages that even hinted there was a physical
singularity at the event horizon, I am well aware
some coordinate system have problems but that is
not what we are arguing about.

George, what I don't get is why there must be a "physical
singularity" at the event horizon, for an internal Universe
to have formed. Physical has a pretty good meaning in
Physics, and we cannot measure anything starting at the event
horizon and including the "inside". What is
fundamentally physical about something you can never
get a reading on?

An observer at great istance cannot get information
from inside the horizon. However the reverse is not
true, As Andrews simulations show, the infalling
observer can still see objects outside.

Now also consider three people roped together falling
in with the rope stretched by the tidal forces (it is
oriented radially). At some instant, the central person
reaches a location which is exactly on the horizon as
determined by an observer far outside. Of course that
observer can no longer see much. The person nearest
the hole is already within the horizon while the third
person is still outside and can wave to the distant
observer.

At that point, I believe the three people can still
communicate both ways, but by the time the third person
hears anything from the first, he too will have fallen
too far to relay the information to the distant observer.

The event horizon no more creates a ne universe than
a one-way mirror and in particular all the laws of
physics apply locally, i.e. between the three victims.
Of course they don't have long to check this but that's
another matter.

That's why I don't consider this a new universe. The
page you cited shows the inside of the cylinder as being
part of this with spacetime being continuous over the
horizon, what isn't shown is where the observer goes
after he hits the singularity. That isn't "in" this
diagram, the suggestion is it might be another universe.

Which is what I feel is *perhaps* experimentally falsifiable.

No, WMAP said it ocurred around 380,000 years and
it's about 6300 years thick from the calculations
we did before. The numbers aren't that exact of
course. However, I still don't understand. Imagine
the universe was a billion light years in every
direction. At 372,300 years it was all filled with
plasma that was sufficiently hot and dense to be
fairly opaque. 6300 years later it had thinned to
the point that it was mostly transparent. What do
you mean by "The plasma would be too thick to fill
760,000 ly"

I misunderstood the significance of the 6300 years.
It is from full opacity, to fully transparent.

Well it is really the length over which the
visibility falls by e^-1. It's easiest to think
in reverse about how far light would penetrate
into the plasma. The probability of a photon
being absorbed depends on the distance so the
number that haven't been absorbed falls
exponentially. That's what the calculation
with the cross section provides. The time for
the material to recombine from transparent to
opaque is much longer as I just discovered,
see my other post on the WMAP results. Overall
we will se a combination of the two effects but
you now understand what I was talking about.

"Understand more", yes.

I thought this "6300ly" (a distance) was the size of
the Universe when the self-exciting plasma decoupled.
In other words, the Universe became "just a little too
large" for light to make it all the way around.

Ah, that explains it. No, the universe was
probably infinite at all times. Your thinking
Newtonian here.

Perhaps.

The universe appears to be flat and would have
been then too. The figure of 1079 is the redshift
compared to today, not the curvature.

An indication of the curvature of the Universe that
emitted the light, vs. the Universe that detected it.

Again your words mean nothing to me. I believe z
is a measure of the angle between two normals to
a surface that has curvature between them, but I
also suspect that's too simplistic. However, I
don't see how you could compute the angle between
two points on curved surfaces in different
universes. How do you calculate across the
discontinuity?

It is continuous between them, isn;t it?

You have been saying there is a singularity between
them.

By the definition of singularity, there is. What is
continuous across the horizon is conservation of
momenergy, conservation of charge, Pauli exclusion, and
perhaps more that I am not aware of.

Spacetime is continuous over the horizon as are
all the laws of physics as viewed by an infalling
observer. Schwarzchild coordinates try to use a
stationary observer which cannot happen, that's
why they fail.

I agree on the reason for the failure of Schwarzchild
coordinates, and that the various conservation laws will hold
locally.

...Last I
heard, there was no Dark Matter at the time of the CMBRM.
Where does this stand now?
...
I haven't seen anything on the subject, one way or the
other in the group. I thought the results of WMAP for
the angular power spectrum were consistent with the
fraction of dark matter found by other means but I
haven't checked the site yet and my memory is poor too.

OK. Another thread, another day.

See my other post. (You just posted a reply
to it, I'll read that next.)

For the CMBR, use this link

http://lambda.gsfc.nasa.gov/product/...prod_table.cfm

Yes. This would be good (as a start) for a free BH, or
^^^^^^^
one near our position in a "largely spiral" galaxy.

I intended that as a good start for the CMBR after
the removal of all stars. You need individual stellar
spectra separately. A free BH has no spectrum since
^^^^^^^
it is black !

The detector of a satellite can behave like a
"differential area" on an event horizon.

Again I have no idea what you mean. If we point a
satellite at a black hole, we don't see the hole,
only the universe behind distorted a bit.

Sigh...
George, I am going to use the recorded spectra, as
detected by "detectors", and infer from that via the
magic of integration, what the EH of a black hole
would ingest over its surface, over its lifetime. I thought
I said this more than once.

OK, maybe I misread you, I thought you were trying
to get satellite readings of the spectrum of an event
horizon itself.

It is the big red nose, orange wig, and big floppy shoes I
normally wear... ;)

Those and your repeated use of "free BH" ;-)

If you want the spectrum of the acretion disk
of an active BH, that's a different matter
entirely.

I want to model (at least) three separate types of black hole:
- one that is sitting in intergalactic space, with no companion,
no accretion (a free BH)
- one that is in a galactic disk, with one or more companions
that it is consuming,
- one that is in the center of a galaxy.

If it is to be done, it should be done more than half-*ssed.

You believe that the images will come in spectrally,
I do not.

That would be inside, we are outside all the black
holes we can use for a reference.

This is what you are comfortable in believing, yes George.

No, you misunderstand, I said we are outside the event
horizon of Cyg X1 and all the other black holes in our
universe which you might look at to get a spectrum to
do your calculations.

And do you not feel that what light is "sprayed out", also
falls back in? Or it expected to be like a laser, and only
"heat" is not directed outwards? I guess I'll do my own
search...

What does that have to do with accusing me
of being "comfortable in believing" we are
outside the event horizon of all the black
holes we can observe? There's a bit of
talking past each other going on here (or
you're pulling my leg vbg!).

I am not pulling your leg. I am probably "frame jumping", from
outside to inside, and back. I keep trying to discuss what is
seen from the inside, and you keep trying to discuss the outside.
We clearly are talking past each other...

David A. Smith