Dear George Dishman:

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

"George Dishman" wrote in message
...

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



Severly trimmed again.

No, that's not true. The failure at the horizon is
purely mathematical as for the pool table example,
the failure at the singularity is physical.

Consider that the sources that are the most active
astrophysically, are black holes (with companions).

Indeed, but the radiation and jets are produced
in the accretion disk outside the horizon.

So it isn't quite "mathematical", then is it?

I don't see your point, the matter in the jets
never gets nearer than r=3m while the horizon
is at r=2m.

My point is that the first singularity is the event horizon. It
is physically not located *in* this Universe. The fact that any
infalling matter starts boiling away due to collisions, even
though the source of the colliding particles is (most commonly)
the same companion, just adds support to my non-specular arrival
of light to the inside.

Physically, the Universe (and the BH) are attempting to solve
the "immovable object/irresistable force" problem.

No, it's more like the gravitational slingshot
of a probe round a planet, it only passes nearby.

.... and nearby ... and nearby ...

Now consider the definition of "singularity". The event
horizon *is* a singularity. No?

No. The singularity is at the centre, there
is nothing unusual physically at the horizon.

It *is* a singularity in Schwarzchild coordinates. I quote
from Wikipedia
a.. mathematical singularity - a point where a mathematical
function goes to infinity or is in certain other ways
ill-behaved.
It is also a point where all functions meet.

OK, that says it is "mathematical", i.e. has no
physical significance.

As with any English word, it has many meanings. The event
horizon meets this constraint as well.

b.. gravitational singularity - an infinity occurring in an
astrophysical model, involving infinite curvature (a
mathematical singularity) in the space/time continuum,
namely a black hole.

OK, that could refer to the centre though there is
nothing in the context to differentiate.

"a black hole" is really clear George. It doesn't try to
differentiate to "internal structure", only for what we *can* see
(in some sense). It clearly doesn't refer to the center, and I
didn't even write it.

What is unusual at the horizon is that light cannot ever
propagate away from it. In all coordinate choices, this
is true.

Yep, ask the duck if there is a ripple on the water
at it's point of no return (see my other post).

So the event horizon *is* a physical singularity, if not a
physical object.

Yes, that's true but if you look at a spacetime
diagram showing light cones, it is obvious why
that occurs and it doesn't involve a singularity.

It does involve a singularity, George. As defined by the
English language. A "singularity" is not always just a
"point".

Sorry, I should have made the distincton between
mathematical and physical.

There is nothing physical about the inside of BH, George. So the
only flashlight we have to view the caverns where Injun Joe hid,
is via mathematics. Some mathematics indicates that we might see
the inside of an event horizon at the beginning of our
Universe... namely the Big Bang.

There is window dressing, but he construction details of the
manequins,
might be there somewhere, but I did not find it. Likely it
was numerical simulation of the equations of GR direct.

Exactly, the only 'assumptions' were the other
stars he included in the hypothetical system.
The ray tracing I believe is pure GR without
any simplifications at all.

I don't know how he did a "Schwarzchild" solution across the
event horizon. Yet that is the suggestion.

Indeed, it is possible and retains discrete images
because the GR model does not include any physical
change at the horizon.

Not and use "Schwarzchild", unless it is well behaved on either
side of the event horizon. Like as not, he did not use anything
Schwarzchild for the "dive into the BH" animations. So we don't
know what he did use. And it is not important, because it is
"only mathematics", right George?

No, it would be better to say "speed_path_average" since
c is just a constant, 299792458m/s.

Yes, sloppy talk does no one any good.

Me too, see above.

You pretty much kick *ss.

would appear to decrease, as observed by an infinite
observer. "Shapiro time delay" is an observation fully in
agreement with GR. So what does it mean to say that
we "infinite observers" can say stuff about physics
beyond the *singularity* that is the event horizon?

David, the event horizon is *not* a singularity,
only certain coordinate system have an *artificial*
singularity on that surface. That is the root of
all our disagreements I think.

It is how the word is defined, George.

I'm not sure of the exact technical definition but
"the boundary of the region from which light cannot
escape" is probably close.

See both defintions of singularity above, and the various pages
you have shown me that Schwarzchild is singular at the EH. "The
singularity at the center" is a non-sequitur, if you don't agree
that mathematics is our road in-and-out. Some of those roads
describe *our* Universe, and the "singularity at the center" as a
very diffuse, cold future.

You (and most other mainstreamers) place the singularity
"at the center", even though this is not physically
meaningful in *this* Universe.

At the centre, many measures become infinite in a
way that is independent of coordinates, the theory
blows up and you have a singularity in the model.
There is no such occurence at the horizon though
some coordiante systems fail.

They *all* fail, George. You yourself use the word "measure".
How would you measure that which can only reliably return your
signal after the black box has evaporated? The English language
is really slippery, I know. But our grandiose posturings:
- about how this Unvierse must be unique,
- the BH must be some sort of cosmic garbage disposal,
- that our continguous-reality-that-passes-for-spacetime must
have a separate life of its own, and extend "recognizeably" even
down into this garbage disposal,
- and violate all the conservation laws just so that we can be
sure that there is a "singularity at the center",
is simply too much for me to believe.

Yet in my hypothesis, the only singularity is the severance of
one spacetime, adjoint to another (essentially identical?)
spacetime.

IMHO, that would be "new physics" since this doesn't
happen in GR.

GR is a theory, which means it has mathematics associated with
it, and not as some sort of unwarranted "apendage". It has
solutions for BHs. All of the solutions (that I have seen) that
do an adequate job of describing massive structures, do so by
either blending or replacing external space with internal time.

....
This is why the r axis is referred to as "timelike".

So time has a different letter in that region,
it is still time.

It *is* still time, but it is not outer-time. It is not
related to
external-time, except perhaps to be orthogonal to it.
Again,
this is just the model, I know.

I don't want to sound as though I'm laying down
the law but I think you need to stop and make
some enquiries. AIUI, it isn't the model, it is
the coordinates. Physically time outside the
horizon and time inside are the same, it is only
when you get to the singularity at the centre
that the physics fails.

Then we can agree to disagree.

I think that's best, I doubt we will resolve this
here but please note I am not rejecting any aspect
of GR, just your interpretation of it. If it turns
out your version is correct, I will happily
acknowledge being enlightened.

Well, it has been "fun", in some sense. I don't expect to be
right. But I do expect me to ask the question, as clearly as
possible, and defend the right for the question to "exist".

....
Yes, it is worth looking but we need to correctly
understand what the models say.

We understand what the models say. Internal time
is NOT directly correlated to external time, by all
metrics than we can yet apply to BHs.

That is where we have agreed to disagree.

OK.

"We can't know." is not very satisfying to me. It seems
that "we can look" is far superior.

Tough. Either we can or we can't, that is
determined by reality, not our preference.
Understanding whether we can or not is the
best we can do.

So why do you have a preference for one model over another?

I don't exclude or prefer any model, other than
perhaps being skeptical of "non-trivial topology"
without convincing evidence, I don't like the
idea of the universe being a Klein Bottle!

Worse than that. A potentially infinite series of such bottles.
Personally, I think it ends at step two, and "where we came from"
and "where our black holes lead" is to one-and-the-same Universe,
primarily anti-matter, and opposite tendency to chirality. But,
that is for another life...

I am not offering "new physics", I am offering that our
Universe is not unique in the scheme of things. And my
hypothesis is potentially falsifiable.

That isn't contentious, it is only your idea of a
physical singularity at the event horizon that I
consideer to be "new physics" as I believe it is
in contradiction to GR.

Only if you consider spacetime to be "physical" is there a
"physcial singularity" at the event horizon. Since:
- there is no spacetime without matter/energy,
- you cannot interact directly with any matter/energy starting at
(really before) the event horizon,
- any infall is already *NOT* in this Universe... only the
gestalt is evident,
- the population must therefore have its own physics, which I
fully expect to be the Pauli exclusion principle, conservation of
momenergy, and so on. I don't expect "new physics", I only
expect continuation of *known* physics.
And like those that don't want to believe that the
reality-dressed-like-spacetime actually binds time to space, I
see you wanting to believe that all such reality continues
"unbroken" inside the event horizon. And we will agree to
disagree.

What is raising the question of a non-closed Universe?

Without dark energy, GR gives some simple
solutions for an expanding universe:

1) Density greater than the critical value
means spatially and temporally finite so
we have a closed universe and a big crunch.
Expansion slows and reverses. A photon
created at t=0 gets exactly half way across
the universe when the crunch arrives.

Which doesn't work too well, since we have photons
arriving in all directions from even ~300,000 y after
the Big Bang.

Why is that relevant, there wasn't a centre as
you know.

Let's see. We can determine the temperature of the CMBR
a "billion years ago" by observing processes in distant
stars.
You have arrived at 4300

6300 LY actually but never mind.

I hope to hold that number.

light years for the thickness of the CMBR. Seems to me like
we are still receiving light that has travelled more than
once
around the size of that early Universe,

Age now is 13.7 billion years. Hypothetically, if
we were in a closed universe currently at maximum
volume, the crunch would be at 27.4 billion years.
In that case GR said it would take a photon
precisely 54.8 billion years to get back to where
it was created after going "once round". The
cosmological constant changes all that though.

even though it may no longer be able to make it
around the size of the Universe now. So the stated
condition "A photon created at t=0 gets exactly
half way across the universe when the crunch
arrives." is obviously not met in this Universe.

Currently a closed universe seems highly unlikely
as we have discussed.

Agreed. You asked me "why" and I was answering that.

Then I still don't understand why you said "Which
doesn't work too well, since we have photons
arriving in all directions from even ~300,000 y
after the Big Bang". They were produced everywhere
so would be arriving from all directions even 1s
after the bang.

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...

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.

The FRW metric has the Universe collapse again, but
after many billions of years.

Exactly.

But it does not "solve" a spacetime that has "chunks" of
mass in it. But then it too is "just a MODEL".

Any solution to the equations is "just a model",
the trick is to find one that matches all we can
observe and then have it tell us about things we
can never see. That's my kind of "what if ...".

But that isn't science, George.

Isn't it? Basing our extrapolations on models derived
from observation instead of philosophy or religion
seems to me to be precisely what science is about.

Models involve mathematics, George.

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.

A photon, once emitted, can be absorbed or scattered.
It cannot be "stretched". The red shift of supernovae
duration is similarly red shifted to its emission spectra.
The light emitted is characteristic of the process that
emitted it, the local curvature in which is was emitted,
the global curvature of the Universe that emitted it, the
global curvature of the Universe that detected/absorbed
it, and the local curvature of the detector. Nothing was
"stretched", any more than it is between the Earth's
surface and the GPS satellites, or between the surface
of the Sun and here.

I hear your assertion.

It is just a lot longer to say... ;)

Ignoring my 'proper motion' part, the kinetic
motion and the "expansion velocity" are one and
the same.

I think that I will stick with Ned Wright's defintion, wherein
"kinetic motion" is kept separate form expansion. "Let
each man lay his dead according to his own fashion."

Can you give me a pointer to this in his tutorial,
I wasn't aware he used the terms. I'll search
later but if you have bookmarked the section it
would save me some time.

I swear it was there explicitly. Any way, as close I can find is
Part 2:
http://www.astro.ucla.edu/~wright/cosmo_02.htm
(without the URL:...)
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.

"What if we find structures the same age as the CMBRM?"

Then the observed nature of those structures is
what we should base our hypotheses on if we are
to approach this scientifically.

Good. Do you agree they *could* be observable... to say
some 500,000 years after the BB... *IF* they existed?

They should be visible after 379,000 years if they
existed then. I am hoping we will see Pop III novae
with the next generation scopes but they are expected
to be around z=20. If super-massive BHs preceded galaxy
formation, we might see quasars even earlier.

To the future then...

"What if we find
heavy elements in excess of what can be explained in
standard Big Bang theory, the same age as the CMBRM?"

Then the measured relative abundances are what we
should base our hypotheses on if we are to approach
this scientifically.

I like to be proactive...

I like the scientific method.

I can't reconcile that statement with your disallowing certain
models of GR.

That's because I don't believe I am, I think you
are inventing "new science" when to suggest a
physical singularity where none exists in GR. If
you want to talk about the Cauchy horizon, that
would be another matter, but I know little of that.

We will agree to disagree.

What is your alternative explanation for the ~24%
observed ratio of He/H not involving the conventional
plasma?

As I have said, I cannot disallow such a plasma. I am
only trying to offer an alternative to said plasma,

Yes, I understand that, but how does your alternative
produce that elemental ratio?

Because that is what infell, was shredded, and recombined, prior
to us becoming large enough to take in structures "whole".

And as I've said, I
might by some stretch of the imagination be right, and there
still be a "Universe filling, opaque plasma".

Then if that rips down matter back to protons
then it wouldn't be an alternative.

They keep talking about "recombination",

It is a misnomer, it should be just "combination",
it's a bit of an in-joke actually.

Perhaps. But many still believe that it started from some
"central singularity", some complex (perhaps) ordered (certainly
bound) state, it had to "de-order" to "get out", then
*recombined* to simpler diffuse forms. Like a white hole (or
evaporating black one), which is hotter than the Universe that
contains it.

snip
Our hole could have formed in an early Universe, and
our hole could have consumed its companion(s) early
on too. Or we could have shredded whatever we got
first... somehow I want to believe we are much bigger
than this.

Bigger than infinite? Do you really mean you want
to believe there an "outside" which is older than
this? See Guth.

No, I want to believe in an outside that is disjoint-in-time
from us.

Then that is 'new physics'

No, it isn't.

I'll continue to disagree on that.

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.

What I meant by "much bigger than this" is, I think we
have too much mass evident today, to have made a
small BH as a "youth".

Too much??? There is only 4% of the critical density
as baryonic matter and even dark matter only brings
it up to about a third of what is required.

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, and still
generate the spectrum. Perhaps this is another lesson for
another day...

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.

That may be a small beginning, but it no less massive.

It still held only 4% of the required matter in
baryonic form.

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?

But I guess we had
to start somewhere. ;)

I just need spectrum data... the Sun, and some of the full
sky surveys
that mapped the CMBR... which will not do a good job with
individual
spectral lines most likely. Do you have some ideas where I
can look?

The Sun isn't going to be much use, you need spectra
for everything from white dwarfs to red giants and you
need to know the mix visible in the container universe
from our location within it and their ages.

These should be written into spectrum data near the plane of
the Milky Way, in the CMBR data... assuming that is available
since it is "contaminated".

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

Then I need to come up with a spectrum for a BH consuming
a companion,

Try Cyg X1

A good search ("Cygnus X1"). I'll see what I can find. Is it
"close" and/or is the line-of-sight pretty clear?

and to somehow infer the influx to the BH at the center of
our own galaxy.

It appears to be in a relatively clear region so
is invisible.

Vaccum cleaners are like that! How about the center of
Andromeda? Is it pretty quiet there also?

....
or Google for "firas data products". It should be on
the Lambda site but that seems to be down at the moment.

Thanks George. I seem to be wearing on your nerves.

Not at all, though I think we have done the
singularity thing to death.

Amen. I'll stick to spectra...

So I will try not to respond more than once a week. That
way the "potential irritation" level is down. It takes me
about an hour to key this all in, and I hope it doesn't take
you nearly this long to reply.

This one took about the same and I haven't looked up
any new references for you. I spent another half hour
or so reading the John Baez pages but I don't count
that as I learn from them anyway.

OK.

(Although a *lot* of thought goes into your responses.)

Thanks, it's nice to know you appreciate it. I could
tell you do the same and while we may disagree I hope
you feel you benefit as much as me from reading the
cited resources.

What fun would it be if everyone agreed with me? I wouldn't get
to learn anything. ;)

Now if I just can...

David A. Smith