"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
...

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
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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.

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.

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.

a.. 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.

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).

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 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.

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.

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.

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.

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.

The mass/energy only "reports to a different boss, on a different form".
What the external Universe calls "an infintely dense central singularity",
the insiders call "an approaching infinitely-diffuse, cold future". We
will evaporate before that will complete, of course.

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.

big snip

I don't hold that this Universe is unique, or at least self-sufficient.

Nor am I claiming that (or otherwise), see my
comments on Guth.

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.

"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!

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.

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.

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'"?

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.

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.

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.

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.

"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.

"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.

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?

and it (my hypothesis) will have a spectrum yet-to-be-determined. I
suspect, as you figured out, a time-integrated external-history will
include a good deal of the BH's own "failed evaporation"... including the
bitter end.

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.

and BHs do tend not to stay one size... as they ingest matter. It could
start out as a shredder, and end up as a flocculation pond (very slow
agitation, that enables agregation of molecules into skimmable or sinkable
structures)

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.

It is a choice of model. And it is potentially observable/falsifiable.

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

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

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

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 !

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

Try Cyg X1

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.

If I'm going to prepare several "broths" best to use many available
spices.

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.

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.

(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.

best regards
George