| Topic: |
Science > Physics |
| User: |
"Roland Paterson-Jones" |
| Date: |
31 Jan 2005 11:53:41 AM |
| Object: |
GR -> Black Holes Can't Form... Take 2 |
OK. I think my previous presentation was too consise for general
consumption. Here's the slow and easy version:
1. Gas clouds in space gather together under gravity. There is no event
horizon.
2. The gas contracts, heats up, and starts to function as a star. Still
no event horizon.
3. The star runs out of gas. Nuclear energy is no longer enough to keep
the matter from collapsing due to gravity (or whatever the reason is,
it's not important). The star starts to collapse in on itself due to
gravity.
4. The star collapses further and gets more dense. As it gets more
dense, its gravity field becomes stronger and stronger. As a result, GR
dictates that there will be an increased time dilation in the strong
gravity field in the star compared to those of us outside the field. The
star will contract ever more slowly to those of us who are outside it.
5. As the collapsing matter approaches critical density for formation of
an event horizon, the time dilation of the nascent black hole will
approach infinity. In particular, those objects (us, for example)
outside the collapsing star will never observe the formation of an event
horizon, nor will ever be able to observe matter crossing the event horizon.
-- Now we take two paths depending on whether we fall into the black
hole or not --
Firstly, the view of those of us outside the black hole:
6. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
7. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
8. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
9. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
10. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
11. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
12. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
OK, I'll stop there ;) The point is that objects external to a black
hole can never observe the formation of one (in finite time).
-- However, from the perspective of matter falling into the black hole --
6.b) A black hole forms and we are inside it! Help!
----------------------------------
Is this an accurate model of what happens?
Regards
Roland
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| User: "" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
02 Feb 2005 02:14:35 PM |
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In sci.physics Roland Paterson-Jones <roland@rolandpj.com> wrote:
OK. I think my previous presentation was too consise for general
consumption. Here's the slow and easy version:
[...]
Firstly, the view of those of us outside the black hole:
6. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
[...]
In a strictly classical description, this is true (although I wouldn't
put it in terms of critical density -- that's an ambiguous term). If
you think about it, it's true by definition. The event horizon is the
boundary beyond which no light can escape; so anything we can *see*
from the outside *must* have come from the time before the collapsing
star was inside its event horizon.
If you add a little bit of quantum mechanics, things are different.
Light is emitted in discrete quantities, as photons, and only a finite
number of photons are emitted before the star crosses the horizon.
If you assume a black body spectrum, you can compute the time the last
photon can be detected by an outside observer, and you find that this
is a finite (short) time after collapse begins. There's a nice discussion
of this at the beginning of chapter 33 of Misner, Thorne, and Wheeler.
If you add *more* quantum mechanics, and try to quantize gravity as well,
it's an open question what happens. There are some plausible guesses,
but they don't agree with each other; until we have a good quantum theory
of gravity, we won't know.
Steve Carlip
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| User: "Dr. Photon" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
09 Feb 2005 02:44:19 PM |
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wrote in message news:<ctrcbb$q40$1@skeeter.ucdavis.edu>...
In sci.physics Roland Paterson-Jones <roland@rolandpj.com> wrote:
OK. I think my previous presentation was too consise for general
consumption. Here's the slow and easy version:
[...]
Firstly, the view of those of us outside the black hole:
6. The star collapses ever more slowly from our outside perspective as
its density increases, never quite reaching critical density for event
horizon creation.
[...]
In a strictly classical description, this is true (although I wouldn't
put it in terms of critical density -- that's an ambiguous term). If
you think about it, it's true by definition. The event horizon is the
boundary beyond which no light can escape; so anything we can *see*
from the outside *must* have come from the time before the collapsing
star was inside its event horizon.
[snip]
and the effective diameter where no light comes from grows in finite
external time, so we see the BH "grow".
What about observation of Hawking radiation?
When an object has "successfully" fallen into a BH, the temperature
should drop. So is it in principle possible (obviously it would be
almost impossible in practice) to monitor the Hawking temperature, and
then decide when the object has fallen in???
Where does Hawking radiation appear to come from? If arbitrarily close
to the horizon, then it will take almost infinite time to reach us?
Is it possible for a photon to be emitted from *very* close to the
event horizon, in a direction in which it should escape, but then for
a very massive body to fall into the BH, so that the EH expands and
swallows the light that was escaping? In other words, when there is
infalling matter, the EH looks like it travels locally faster than
light?
(maybe I should start another thread! :))
BR
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
02 Feb 2005 04:24:41 PM |
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To Roland, Eric and Steve...
carlip-nos...@physics.ucdavis.edu wrote:
In sci.physics Roland Paterson-Jones <roland@rolandpj.com> wrote:
If you add *more* quantum mechanics, and try to quantize gravity as
well,
it's an open question what happens. There are some plausible
guesses,
but they don't agree with each other; until we have a good quantum
theory
of gravity, we won't know.
Steve Carlip
I'm glad Steve posted here.
The Bergmann ref I provided in this thread, has Einstein
predicting particles
"begin to move with the the velocity of light"
as Bergmann quotes. IMO Bergmann is as good as
any GR genious, so I'm presuming Einstein and Bergmann
are credible.
Now Bergmann follows up in his book, pq 204,
"Einstein's result can be extended to conglomerations
of particles"
I'm presuming "conglomerations" means Baryons,
and I'm presuming "particles begin moving at the
speed of light" are leptons, ultimately gamma rays
and neutrino's.
Their hypothesis *suggests* questioning Baryon
conservation, and IMO predicts it.
As a side note, I investigated if the pressure
within a neutrom star would cause baryons to
decay to photons, I find the affirmative, in
accord with Einstein and Bergmann.
In 1939 neutron stars were unknown, yet it's
my interpretation that Einstein's 1939 paper
(and he was fully cognizant of quantum
conservation laws), specifically said a very
powerful g-field will convert particles (Baryons)
to leptons, aka (particle moving at the speed of
light).
Hey guy's it's 2005, and Einstein's moxy is
still around.
Einstein and Bergmann's opinions are often
considered dated, and fringe physics, and I
won't have bothered posting except that, GRB's
are very real evidently, and appear as a
prediction.
Well someone should argue that viewpoint.
Ken S. Tucker
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| User: "Tom Roberts" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
01 Feb 2005 09:02:47 AM |
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Roland Paterson-Jones wrote:
[...]
See my post in the thread with subject "GR -> Black Holes Can't Form...".
Yes, we here on earth cannot see the completion of the formation of a distant
black hole. But that does not matter, because we can observe a modest distance
outside the horizon, and that includes points well inside the innermost stable
orbit (which is what astronomers are citing as evidence for the existence of
black holes).
Tom Roberts tjroberts@lucent.com
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
01 Feb 2005 09:50:17 AM |
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Tom Roberts wrote:
Roland Paterson-Jones wrote:
[...]
See my post in the thread with subject "GR -> Black Holes Can't
Form...".
Yes, we here on earth cannot see the completion of the formation of a
distant
black hole. But that does not matter, because we can observe a modest
distance
outside the horizon, and that includes points well inside the
innermost stable
orbit (which is what astronomers are citing as evidence for the
existence of
black holes).
You don't mean we have imaged a black hole, do you?
Those orbits are damn close to the event horizon, which surprises me
beacuse I haven't heard of that being done.
If that is not what you mean, I will guess that you meant all those
objects that we have observed to have a large amount of mass stuffed
inside a very small volume. I'm thinking of things like the Cygnus dark
companion and the central black hole.
Tom Roberts tjroberts@lucent.com
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| User: "Tom Roberts" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
02 Feb 2005 07:41:38 PM |
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Eric Gisse wrote:
Tom Roberts wrote:
Yes, we here on earth cannot see the completion of the formation of a
distant
black hole. But that does not matter, because we can observe a modest
distance
outside the horizon, and that includes points well inside the
innermost stable
orbit (which is what astronomers are citing as evidence for the
existence of black holes).
You don't mean we have imaged a black hole, do you?
No. They claim to have observed the innermost stable orbit of matter
around a black hole. I don't know the details, but I'm pretty sure they
measured red/blueshifts on opposite sides, and from that and the mass of
the object (determined from gravitational orbits around it), they
deduced the inner limit of the accretion disk was consistent with a
black hole.
Those orbits are damn close to the event horizon, which surprises me
beacuse I haven't heard of that being done.
For a Schwarzschild black hole, the innermost stable orbit is at r=6M,
which is three times the "radius" of the horizon. There is an unstable
circular orbit for light at r=3M.
all those
objects that we have observed to have a large amount of mass stuffed
inside a very small volume. I'm thinking of things like the Cygnus dark
companion and the central black hole.
That, too.
Tom Roberts tjroberts@lucent.com
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 02:33:20 AM |
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Tom Roberts wrote:
Eric Gisse wrote:
Tom Roberts wrote:
Yes, we here on earth cannot see the completion of the formation of
a
distant
black hole. But that does not matter, because we can observe a
modest
distance
outside the horizon, and that includes points well inside the
innermost stable
orbit (which is what astronomers are citing as evidence for the
existence of black holes).
You don't mean we have imaged a black hole, do you?
No. They claim to have observed the innermost stable orbit of matter
around a black hole. I don't know the details, but I'm pretty sure
they
measured red/blueshifts on opposite sides, and from that and the mass
of
the object (determined from gravitational orbits around it), they
deduced the inner limit of the accretion disk was consistent with a
black hole.
I didn't know we had the resolution to do that. Deeply cool.
Link/cite?
It would have to be either a really close and really small black hole
[Hmm, whats the closest known BH?] or far away and really big. The only
'far away and really big' black hole that I know of the the central
core.
If I had to guess, I would say it is the central core black hole that
your talking about. We have directly imaged a star traveling at an
insane speed [non-relativistic, but damn fast] around a central mass.
The mass of the object thats the star was orbiting was pegged at
several million solar masses and was calculated to orbit around it
every 17 years or so. That orbital period isn't *that* large, so mabey
it is possible they could get decent observations of the red/blue shift
of that star. That said, I don't know how close it is thought to be to
the central core.
Those orbits are damn close to the event horizon, which surprises
me
beacuse I haven't heard of that being done.
For a Schwarzschild black hole, the innermost stable orbit is at
r=6M,
which is three times the "radius" of the horizon. There is an
unstable
circular orbit for light at r=3M.
I meant not htat I didn't know there were stable orbits, but that we
had imaged anything close enough TO the last stable orbits for them to
be of any note outside of a theoretical exercise.
Then again, if the black hole is really massive, 6M just might be a
large number.
all those
objects that we have observed to have a large amount of mass
stuffed
inside a very small volume. I'm thinking of things like the Cygnus
dark
companion and the central black hole.
That, too.
Tom Roberts tjroberts@lucent.com
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 03:49:01 AM |
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Eric,
It's difficult to differentiate between a BH and a neutron star.
For fun, have a study of the M13 globular cluster, IIRC
it's a fuzzy patch in the constellation Hercules.
We cannot rule out the possiblity of such clusters existing
that are composed of n-stars, particularily the older stars
that tend to migrate into the center of our galaxy, but are
not visually apparent.
Our rush to find BH's may blind us from adequate
consideration of more conventional systems that
are just as exciting, and perhaps provide more data
about the galatic neighbourhood, and it's evolution.
Ken
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 07:01:10 AM |
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Ken S. Tucker wrote:
Eric,
It's difficult to differentiate between a BH and a neutron star.
Sometimes but not always.
For fun, have a study of the M13 globular cluster, IIRC
it's a fuzzy patch in the constellation Hercules.
Within 25kly, within our galaxy. What about it?
We cannot rule out the possiblity of such clusters existing
that are composed of n-stars, particularily the older stars
that tend to migrate into the center of our galaxy, but are
not visually apparent.
Eh. I have no idea what the composition of M13 is, but im willing to
bet that there is at least 1 neutron star in there. But since we can
*SEE* it with visible light, it is not composed entirely of neutron
stars - that is trivially checkable.
I was not aware that old stars migrate anywhere other than to the next
point of their orbit. What forces them to the center of the galaxy?
I don't see your point. The composition of any random chunk of the sky
is going to have variety...
Our rush to find BH's may blind us from adequate
consideration of more conventional systems that
are just as exciting, and perhaps provide more data
about the galatic neighbourhood, and it's evolution.
The Chandreskahar limit is ~1.5 solar masses. When you see a body
orbiting a dark companion that is figured to be much more than 1.5
solar masses, what can it be? There isn't enough time elapsed in the
universe for a neutron star to sufficiently cool down to
undetectability, and there is no intermediate object that I know of
that exists between the realm of 'neutron star' and 'black hole' in
terms of mass per occupied volume. If you eliminate the neutron star,
what else is there?
Don't forget that astronomy is not an organization with a coherant
viewpoint on how things are or how they should be. When something that
is even slightly controversial is revealed, it will be gone over with a
fine tooth comb.
Ken
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 05:40:28 PM |
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Eric Gisse wrote:
Ken S. Tucker wrote:
Eric,
It's difficult to differentiate between a BH and a neutron star.
Sometimes but not always.
For fun, have a study of the M13 globular cluster, IIRC
it's a fuzzy patch in the constellation Hercules.
Within 25kly, within our galaxy. What about it?
We cannot rule out the possiblity of such clusters existing
that are composed of n-stars, particularily the older stars
that tend to migrate into the center of our galaxy, but are
not visually apparent.
Eh. I have no idea what the composition of M13 is, but im willing to
bet that there is at least 1 neutron star in there. But since we can
*SEE* it with visible light, it is not composed entirely of neutron
stars - that is trivially checkable.
I was not aware that old stars migrate anywhere other than to the
next
point of their orbit. What forces them to the center of the galaxy?
I could only speculate about that, it's related to
population 1 and 2 stars, and galatic evolution.
I don't see your point. The composition of any random chunk of the
sky
is going to have variety...
Our rush to find BH's may blind us from adequate
consideration of more conventional systems that
are just as exciting, and perhaps provide more data
about the galatic neighbourhood, and it's evolution.
The Chandreskahar limit is ~1.5 solar masses. When you see a body
orbiting a dark companion that is figured to be much more than 1.5
solar masses, what can it be?
It would be interesting, possibly mysterious.
There isn't enough time elapsed in the
universe for a neutron star to sufficiently cool down to
undetectability, and there is no intermediate object that I know of
that exists between the realm of 'neutron star' and 'black hole' in
terms of mass per occupied volume. If you eliminate the neutron star,
what else is there?
There's been really no serious need for that
type of speculation that I'm aware of.
Don't forget that astronomy is not an organization with a coherant
viewpoint on how things are or how they should be. When something
that
is even slightly controversial is revealed, it will be gone over with
a
fine tooth comb.
Hopefully, considering the scrutiny taken to confirm
GR's light deflection etc...BH claims must require
good analysis.
Ken
.
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 06:40:54 PM |
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Ken S. Tucker wrote:
[snip]
I was not aware that old stars migrate anywhere other than to the
next
point of their orbit. What forces them to the center of the galaxy?
I could only speculate about that, it's related to
population 1 and 2 stars, and galatic evolution.
I am not even aware of the existance of such a force on old stars. Pop
1 and 2 stars comprise EVERYTHING we see, all the pop 3 stars are gone.
If there was really a force that was dragging pop 1 and 2 stars out of
their orbit and into the center of the galaxy, it would be interesting
to see an explanation of why galaxys still exist.
I don't see your point. The composition of any random chunk of the
sky
is going to have variety...
Our rush to find BH's may blind us from adequate
consideration of more conventional systems that
are just as exciting, and perhaps provide more data
about the galatic neighbourhood, and it's evolution.
The Chandreskahar limit is ~1.5 solar masses. When you see a body
orbiting a dark companion that is figured to be much more than 1.5
solar masses, what can it be?
It would be interesting, possibly mysterious.
My point is that the choices are rather small.
There isn't enough time elapsed in the
universe for a neutron star to sufficiently cool down to
undetectability, and there is no intermediate object that I know of
that exists between the realm of 'neutron star' and 'black hole' in
terms of mass per occupied volume. If you eliminate the neutron
star,
what else is there?
There's been really no serious need for that
type of speculation that I'm aware of.
Look more carefully. Some people really don't like black holes and dig
hard for stuff that can prevent the creation of a black hole. Things
like quark stars come to mind, along with a recent guess of an object
from string theory which would have a somehow-stable shell of matter an
epsilon above the event horizon of a black hole.
The shell star has....difficulties....regarding stability and entropy,
come to think of it. I haven't heard much about that recently.
Don't forget that astronomy is not an organization with a coherant
viewpoint on how things are or how they should be. When something
that
is even slightly controversial is revealed, it will be gone over
with
a
fine tooth comb.
Hopefully, considering the scrutiny taken to confirm
GR's light deflection etc...BH claims must require
good analysis.
I am not disagreeing, but arguing just for the sake of arguing doesn't
have any real allure for me. Yes, checking is important but checking
just for the sake of doing it doesn't interest me. If there is any
question about the status of something, then by all means check. But
don't say 'well you never know...' because you might have vauge
uncertainties regarding the existance of black holes.
Check out the Cygnus system [Remember Hawking's bet?] and the central
core in the direction of Saggitarius A*.
Ken
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 07:08:50 PM |
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Eric Gisse wrote:
Ken S. Tucker wrote:
[snip]
I was not aware that old stars migrate anywhere other than to the
next
point of their orbit. What forces them to the center of the
galaxy?
I could only speculate about that, it's related to
population 1 and 2 stars, and galatic evolution.
I am not even aware of the existance of such a force on old stars.
Pop
1 and 2 stars comprise EVERYTHING we see, all the pop 3 stars are
gone.
If there was really a force that was dragging pop 1 and 2 stars out
of
their orbit and into the center of the galaxy, it would be
interesting
to see an explanation of why galaxys still exist.
Ok, when I entered this thread, I did so with
a specific reference to Bergmann, about BH's.
I didn't really want to debate fuzzy astronomy
pictures, it's a bit subjective for me.
I don't see your point. The composition of any random chunk of
the
sky
is going to have variety...
Our rush to find BH's may blind us from adequate
consideration of more conventional systems that
are just as exciting, and perhaps provide more data
about the galatic neighbourhood, and it's evolution.
The Chandreskahar limit is ~1.5 solar masses. When you see a body
orbiting a dark companion that is figured to be much more than
1.5
solar masses, what can it be?
It would be interesting, possibly mysterious.
My point is that the choices are rather small.
Suppose you see a ghost, please explain the
theory of ghosts, I'd wait until one actually
sees the ghost before inventing a theory of
ghosts.
There isn't enough time elapsed in the
universe for a neutron star to sufficiently cool down to
undetectability, and there is no intermediate object that I know
of
that exists between the realm of 'neutron star' and 'black hole'
in
terms of mass per occupied volume. If you eliminate the neutron
star,
what else is there?
There's been really no serious need for that
type of speculation that I'm aware of.
Look more carefully. Some people really don't like black holes and
dig
hard for stuff that can prevent the creation of a black hole. Things
like quark stars come to mind, along with a recent guess of an object
from string theory which would have a somehow-stable shell of matter
an
epsilon above the event horizon of a black hole.
The shell star has....difficulties....regarding stability and
entropy,
come to think of it. I haven't heard much about that recently.
Don't forget that astronomy is not an organization with a
coherant
viewpoint on how things are or how they should be. When something
that
is even slightly controversial is revealed, it will be gone over
with
a
fine tooth comb.
Hopefully, considering the scrutiny taken to confirm
GR's light deflection etc...BH claims must require
good analysis.
I am not disagreeing, but arguing just for the sake of arguing
doesn't
have any real allure for me. Yes, checking is important but checking
just for the sake of doing it doesn't interest me. If there is any
question about the status of something, then by all means check. But
don't say 'well you never know...' because you might have vauge
uncertainties regarding the existance of black holes.
My uncertainities are not vague, BH's certainly do not
exist in nature.
Check out the Cygnus system [Remember Hawking's bet?] and the central
core in the direction of Saggitarius A*.
Noted, sounds like fun, good review.
Ken
.
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 09:56:51 PM |
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Ken S. Tucker wrote:
Eric Gisse wrote:
Ken S. Tucker wrote:
[snip]
I was not aware that old stars migrate anywhere other than to
the
next
point of their orbit. What forces them to the center of the
galaxy?
I could only speculate about that, it's related to
population 1 and 2 stars, and galatic evolution.
I am not even aware of the existance of such a force on old stars.
Pop
1 and 2 stars comprise EVERYTHING we see, all the pop 3 stars are
gone.
If there was really a force that was dragging pop 1 and 2 stars out
of
their orbit and into the center of the galaxy, it would be
interesting
to see an explanation of why galaxys still exist.
Ok, when I entered this thread, I did so with
a specific reference to Bergmann, about BH's.
I didn't really want to debate fuzzy astronomy
pictures, it's a bit subjective for me.
I don't see your point. The composition of any random chunk of
the
sky
is going to have variety...
Our rush to find BH's may blind us from adequate
consideration of more conventional systems that
are just as exciting, and perhaps provide more data
about the galatic neighbourhood, and it's evolution.
The Chandreskahar limit is ~1.5 solar masses. When you see a
body
orbiting a dark companion that is figured to be much more than
1.5
solar masses, what can it be?
It would be interesting, possibly mysterious.
My point is that the choices are rather small.
Suppose you see a ghost, please explain the
theory of ghosts, I'd wait until one actually
sees the ghost before inventing a theory of
ghosts.
The theory of black holes existed long before the observation of them,
indirect or otherwise.
Black holes date back to the time of Oppenheimer.
There isn't enough time elapsed in the
universe for a neutron star to sufficiently cool down to
undetectability, and there is no intermediate object that I
know
of
that exists between the realm of 'neutron star' and 'black
hole'
in
terms of mass per occupied volume. If you eliminate the neutron
star,
what else is there?
There's been really no serious need for that
type of speculation that I'm aware of.
Look more carefully. Some people really don't like black holes and
dig
hard for stuff that can prevent the creation of a black hole.
Things
like quark stars come to mind, along with a recent guess of an
object
from string theory which would have a somehow-stable shell of
matter
an
epsilon above the event horizon of a black hole.
The shell star has....difficulties....regarding stability and
entropy,
come to think of it. I haven't heard much about that recently.
Don't forget that astronomy is not an organization with a
coherant
viewpoint on how things are or how they should be. When
something
that
is even slightly controversial is revealed, it will be gone
over
with
a
fine tooth comb.
Hopefully, considering the scrutiny taken to confirm
GR's light deflection etc...BH claims must require
good analysis.
I am not disagreeing, but arguing just for the sake of arguing
doesn't
have any real allure for me. Yes, checking is important but
checking
just for the sake of doing it doesn't interest me. If there is any
question about the status of something, then by all means check.
But
don't say 'well you never know...' because you might have vauge
uncertainties regarding the existance of black holes.
My uncertainities are not vague, BH's certainly do not
exist in nature.
http://www.sciam.com/article.cfm?articleID=0007BAC3-CD4F-1DAD-94E2809EC5880108
http://www.eso.org/outreach/press-rel/pr-2002/pr-17-02.html
http://www.space.com/scienceastronomy/astronomy/mw_blackhole_010905.html
http://www.newscientist.com/article.ns?id=dn6937
http://chandra.harvard.edu/photo/2003/0203long/
What exotic configuration of matter do you suggest that will do this?
Remember - 2.6 million solar masses. A star is orbiting it at 5000
km/s, with Sgr. A* as one of the focal points and with 17 light hours
of it at its' closest.
That would be something to see...
http://www.eso.org/outreach/press-rel/pr-2002/phot-23c-02-preview.jpg
Check out the Cygnus system [Remember Hawking's bet?] and the
central
core in the direction of Saggitarius A*.
Sagittarius, actually. I can't spell.
Noted, sounds like fun, good review.
Ken
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 10:12:37 PM |
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Eric,
Schwarzchild, Einstein, Weinberg, Bergmann, Lottinger and
me Tucker, find BH's impossible. If astronomers can explain
why those theoreticians are all wrong why haven't they.
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
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| User: "JM Albuquerque" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
04 Feb 2005 06:17:07 PM |
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"Ken S. Tucker" <dynamics@vianet.on.ca> escreveu na mensagem
news:1107490357.372967.168970@o13g2000cwo.googlegroups.com...
Eric,
(snip)
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
The error exists.
What was it is the reason that keeps us here.
I bet the problem is with the light and Hubble.
I hope to know one day what the error really is.
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| User: "Androcles Androcles@ MyPlace.org" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 10:33:20 PM |
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"Ken S. Tucker" <dynamics@vianet.on.ca> wrote in message
news:1107490357.372967.168970@o13g2000cwo.googlegroups.com...
Eric,
Schwarzchild, Einstein, Weinberg, Bergmann, Lottinger and
me Tucker, find BH's impossible. If astronomers can explain
why those theoreticians are all wrong why haven't they.
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
I'd tell you, but you'd never believe it anyway.
Androcles
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| User: "" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
07 Feb 2005 04:35:18 PM |
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In sci.physics Ken S. Tucker <dynamics@vianet.on.ca> wrote:
Schwarzchild,
Really? Evidence, please...
Einstein,
Einstein's paper on this, Ann. Math. 40 (1939) 922, is entitled
"On a Stationary System With Spherical Symmetry Consisting of
Many Gravitating Masses." If you think about the title, you
should be able to see why he was asking the "wrong" question --
that is, a question that is not relevant to the behavior of real
black holes.
Einstein looked at a *stationary* collection of particles, that
is, a collection of particles in circular orbits whose average
distribution was not changing in time, and asked whether you could
put enough of them together to make a black hole. He answered,
correctly, that you can't; this would require orbital speeds
exceeding c. But that's not relevant to the formation of a real
black hole. The matter inside the event horrizon cannot be
stationary; it cannot move in circular orbits, but must necessarily
fall inwards. Einstein's paper did not address this possibility,
because he, like almost all of his contemporaries, thought of
a black hole as a stationary, time-independent object, not one
undergoing continuing collapse.
Weinberg,
Nonsense! Weinberg certainly does not "find black holes impossible."
You have made this up.
Bergmann,
In a 50-year-old book. Einstein, unfortunately, did not live long
enough to see the confusion about black holes straightened out.
Bergmann did. If you look at the 1968 edittion of _The Riddle of
Gravitation_, for example, you will see that he says there is "no doubt"
that a sufficiently large mass will collapse and form an event horizon.
Lottinger
[Loinger] Yes, you finally found someone who agrees with you. This is
someone with eight preprints on this topic, seven unpublished and one
that appeared in a crank journal.
and me Tucker, find BH's impossible.
If you want to argue against the existence of black holes, fine. But
don't make up support where it doesn't exist.
If you believe that general relativity doesn't allow black holes, here's
a suggestion. Look up the paper gr-qc/0310122, which obtains an exact
solution to the Einstein field equations describing the collapse of a
fluid to form a black hole. Go through the paper, and find something
wrong with the math. Then publish.
(I chose this one randomly; there are many other papers giving exact
solutions to the field equations describing the collapse of various kinds
of matter and radiation. By all means, try to find a flaw...)
Steve Carlip
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
07 Feb 2005 06:25:59 PM |
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wrote:
In sci.physics Ken S. Tucker <dynamics@vianet.on.ca> wrote:
Schwarzchild,
Really? Evidence, please...
See physics/9905030, Eq. (13), the discontinuity
is set to the origin.
Einstein,
Einstein's paper on this, Ann. Math. 40 (1939) 922, is entitled
"On a Stationary System With Spherical Symmetry Consisting of
Many Gravitating Masses." If you think about the title, you
should be able to see why he was asking the "wrong" question --
that is, a question that is not relevant to the behavior of real
black holes.
Einstein looked at a *stationary* collection of particles, that
is, a collection of particles in circular orbits whose average
distribution was not changing in time, and asked whether you could
put enough of them together to make a black hole. He answered,
correctly, that you can't; this would require orbital speeds
exceeding c. But that's not relevant to the formation of a real
black hole. The matter inside the event horrizon cannot be
stationary; it cannot move in circular orbits, but must necessarily
fall inwards. Einstein's paper did not address this possibility,
because he, like almost all of his contemporaries, thought of
a black hole as a stationary, time-independent object, not one
undergoing continuing collapse.
Bergmann in 1976 edition, "Intro..." pg. 204.
"Einstein's result...conglomerations of particles".
Weinberg,
Nonsense! Weinberg certainly does not "find black holes impossible."
You have made this up.
See Weinberg's "Grav & Cosmo" bottom of pg. 208.
"like Aesop's fables..."
Bergmann,
In a 50-year-old book. Einstein, unfortunately, did not live long
enough to see the confusion about black holes straightened out.
Bergmann did. If you look at the 1968 edittion of _The Riddle of
Gravitation_, for example, you will see that he says there is "no
doubt"
that a sufficiently large mass will collapse and form an event
horizon.
Sorry don't have that ref. He writes in 1976,
in apparent agreement with Einstein, as I refd
above. Maybe you could email him.
[Loinger] Yes, you finally found someone who agrees with you. This
is
someone with eight preprints on this topic, seven unpublished and one
that appeared in a crank journal.
and me Tucker, find BH's impossible.
If you want to argue against the existence of black holes, fine. But
don't make up support where it doesn't exist.
I didn't do that, your accusation is unfounded,
but your challenge is respected.
If you believe that general relativity doesn't allow black holes,
here's
a suggestion. Look up the paper gr-qc/0310122, which obtains an
exact
solution to the Einstein field equations describing the collapse of a
fluid to form a black hole. Go through the paper, and find something
wrong with the math.
I did, he set Newton's Big G=1, he also
sets c=1, I doubt that holds in the
neighbourhood of a powerful g-field.
Then publish.
(I chose this one randomly; there are many other papers giving exact
solutions to the field equations describing the collapse of various
kinds
of matter and radiation. By all means, try to find a flaw...)
Steve Carlip
It's easier to do it right.
Ken S. Tucker
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
07 Feb 2005 08:14:50 PM |
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Ken S. Tucker wrote:
carlip-nospam@physics.ucdavis.edu wrote:
In sci.physics Ken S. Tucker <dynamics@vianet.on.ca> wrote:
Schwarzchild,
Really? Evidence, please...
See physics/9905030, Eq. (13), the discontinuity
is set to the origin.
No *****. What is your point? The singularity at the origin is nothing
new and is the stereotypical flaw of GR, even if QM is pushed off to
the side. Just because there is a nonsingular point somewhere in the
metric does not mean the solution is invalid everywhere as you like to
imply.
Lets look at everyone's favorite trig function: tan(x). tan(x) has
singularities at +/- npi/2, n = 1,3,5,7....
Does that mean tan(x) is invalid? Or does it simply mean that you
cannot use it at the singular points? If I carry your analogy out to
other functions, it certaintly is - but that is frankly *****, as
even you should be able to see.
I can pull any number of functions out of my ***** which contain singular
points which are valid when the singularities are avoided.
BTW, at the risk of incurring the "semantics" as you trivially called
them...
Schwarzschild has never said black holes are impossible, least of all
because he was dead a half century before the term was coined by
Wheeler. The only person saying they are impossible is the
interpretation of Schwarzschild's work by you and Loinger. They do not
share the exact same meanings, stop dragging Schwarzschild's name
through the mud.
[snip]
I did, he set Newton's Big G=1, he also
sets c=1, I doubt that holds in the
neighbourhood of a powerful g-field.
[snip]
Come on, Ken...
Are you seriously arguing that rescaling fundamental constants to be
equal to one is an invalid practice?
You might wanna publish that, it's much bigger than a LPU because
somehow somewhere the fundamental constants are no longer constant and
thus break a very, very large chain of pulling them outside
derivatives. That would mean they are not invariants as was once
thought, and becomes a Big Fucking Deal(tm).
Hmm. Time to retreat back into reality...you have no idea what you are
talking about. Setting c = 1 means you rescale your velocities in terms
of fractions of c. I'm surprised I have to explain that to you. It is
not a new concept nor have I ever heard it argued against until right
now. Even Androcles understands the concept of rescaling - or mabey he
simply never got that far. Either way...
Ken, why is it that I have a more functional understanding of GR than
yourself while I admittedly do not understand a fair bit of the math?
You must have picked these ideas up from somewhere - what can be
learned can be unlearned.
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
09 Feb 2005 03:08:49 AM |
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Eric, in your post you reasonably question
my understanding of GR, however I'm rather
concerned if you understand how sophisticated
the subject is.
There are two GR's for anyone, the one you
are taught and the one you learn. The taught
is always simpler...
Eric Gisse wrote:
Ken S. Tucker wrote:
carlip-nospam@physics.ucdavis.edu wrote:
In sci.physics Ken S. Tucker <dynamics@vianet.on.ca> wrote:
Schwarzchild,
Really? Evidence, please...
See physics/9905030, Eq. (13), the discontinuity
is set to the origin.
No *****. What is your point?
You really don't know do you?
The singularity at the origin is nothing
new and is the stereotypical flaw of GR,
Oh-boy, that's new, "stereotypical flaw"
as opposed to a *typical flaw*, flaws
come in stereo-phonics now.
even if QM is pushed off to
the side. Just because there is a nonsingular point somewhere in the
metric does not mean the solution is invalid everywhere as you like
to
imply.
Is this what I get for quoting an equation?
Lets look at everyone's favorite trig function: tan(x). tan(x) has
singularities at +/- npi/2, n = 1,3,5,7....
Does that mean tan(x) is invalid? Or does it simply mean that you
cannot use it at the singular points? If I carry your analogy out to
other functions, it certaintly is - but that is frankly *****, as
even you should be able to see.
Yes, I can see it is.
I can pull any number of functions out of my ***** which contain
singular
points which are valid when the singularities are avoided.
BTW, at the risk of incurring the "semantics" as you trivially called
them...
Schwarzschild has never said black holes are impossible,
Evidently you do not understand his Eq.(13) that
respects the relation of mass and length. It is
difficult for us Euclidians to understand KS's
genius when he subbed R for r in his solution.
A masterful, though apparently confusing stroke.
least of all
because he was dead a half century before the term was coined by
Wheeler. The only person saying they are impossible is the
interpretation of Schwarzschild's work by you and Loinger. They do
not
share the exact same meanings, stop dragging Schwarzschild's name
through the mud.
Say what, I'm the guy who introduced the KS ref
and pointed out KS's eq (13), I regret you're
emotionally attached to the subject, perhaps you
need a bit of perspective.
I did, he set Newton's Big G=1, he also
sets c=1, I doubt that holds in the
neighbourhood of a powerful g-field.
Come on, Ken...
Are you seriously arguing that rescaling fundamental constants to be
equal to one is an invalid practice?
Normally no, but when we start examining the
powerful effects of spacetime curvature near
a massive body, we need much more care.
IMO G is not invariant, and c is only an
invariant in a vacuum. In the presence of
a strong g-field these become proportional
to,
K => G*g^uv , C => c*g_uv
in practical terms. The C is well confirmed
experimentally, the K is a theoretical
necessity.
You might wanna publish that, it's much bigger than a LPU
what's "LPU"?
because
somehow somewhere the fundamental constants are no longer constant
and
thus break a very, very large chain of pulling them outside
derivatives. That would mean they are not invariants as was once
thought, and becomes a Big Fucking Deal(tm).
Hmm. Time to retreat back into reality...you have no idea what you
are
talking about. Setting c = 1 means you rescale your velocities in
terms
of fractions of c. I'm surprised I have to explain that to you. It is
not a new concept nor have I ever heard it argued against until right
now. Even Androcles understands the concept of rescaling - or mabey
he
simply never got that far. Either way...
Ken, why is it that I have a more functional understanding of GR than
yourself while I admittedly do not understand a fair bit of the math?
GR in our solar system is like taking a little
red wagon around the block, GR with EM, QT and
BH's is more like flying an SR-71, I defer to
you're skill with a wagon.
You must have picked these ideas up from somewhere - what can be
learned can be unlearned.
Yup, a blonde with a cattle prod will do it.
Eric, I enjoyed your emotional outburst, do
you care to persue the subject objectively,
or do you just want to have fun? We could
do both.
Ken S. Tucker
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
03 Feb 2005 11:59:18 PM |
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Ken S. Tucker wrote:
Eric,
Schwarzchild, Einstein, Weinberg, Bergmann, Lottinger and
me Tucker, find BH's impossible. If astronomers can explain
why those theoreticians are all wrong why haven't they.
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
Schwarzschild? No way I will believe that without a citation.
Especially considering the rather...short...period between his
publishing of his solution and his untimely death in the trenches of
WW1.
Einstein? What of him?
Einstein's grave probably has a decent amount of spin because the
quantum statistics he disliked and the black holes he did not believe
in were united in a unholy duality...
Again, I am not familiar with Bergmann' or Lottinger's arguments
against black holes.
I also did not know Weinberg held a technical opinion against black
holes - his field of study is tilted towards particle physics.
Again, what is hiding at Sgr. A* and Cyg. X-1?
Sgr. A* has 2.6 million solar masses stuffed inside roughly 9 square
light years. 9 light years is big, 2.6 million suns is even bigger.
What is it?
Cyg. X-1 has a blue supergiant orbiting around a dark companion that
spits out an insane amount of X-rays and has a mass of 8-10 solar
masses. What is it?
Cygnus X-1 and Sgr. A* have sold me on the existance of black holes.
Not only is it a real cool object, but it really tweaks the people who
hate relativity.
BTW, ignore Androcles. He is a certified idiot.
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
04 Feb 2005 11:21:59 AM |
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Eric Gisse wrote:
Ken S. Tucker wrote:
Eric,
Schwarzchild, Einstein, Weinberg, Bergmann, Lottinger and
me Tucker, find BH's impossible. If astronomers can explain
why those theoreticians are all wrong why haven't they.
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
Schwarzschild? No way I will believe that without a citation.
Especially considering the rather...short...period between his
publishing of his solution and his untimely death in the trenches of
WW1.
I mispelled, Lottinger should be LOINGER.
He has posted a translation of Schwarzchild's
original work in arXiv. I usually have the
paper handy but my temp office is a mess.
A search will turn it up, we can discuss that
if you want, instead of Bergmann's text.
How are you at math and tensors?
Ken
....
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| User: "Eric Gisse" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
04 Feb 2005 11:38:20 PM |
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Ken S. Tucker wrote:
Eric Gisse wrote:
Ken S. Tucker wrote:
Eric,
Schwarzchild, Einstein, Weinberg, Bergmann, Lottinger and
me Tucker, find BH's impossible. If astronomers can explain
why those theoreticians are all wrong why haven't they.
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
Schwarzschild? No way I will believe that without a citation.
Especially considering the rather...short...period between his
publishing of his solution and his untimely death in the trenches
of
WW1.
I mispelled, Lottinger should be LOINGER.
He has posted a translation of Schwarzchild's
original work in arXiv. I usually have the
paper handy but my temp office is a mess.
A search will turn it up, we can discuss that
if you want, instead of Bergmann's text.
http://xxx.lanl.gov/PS_cache/physics/pdf/0402/0402088.pdf
This appears to be the crux of his argument:
"The HDW-form is physically valid only for r > 2m, because within the
spatial surface r = 2m (a singular locus) the time co-ordinate takes
the role of the radial co-ordinate, and vice versa (and therefore ds2
loses its essential property of physical appropriateness) and the
solution becomes non-static."
It appears that he is saying beyond r = 2m the Schwarzchild solution [I
never heard it called HDW until today...*shrug*] is a physical one and
thus acceptable. I have always understood this to mean the coordinates
outside the event-horizon are time-like - moving along a geodesic
outside of r = 2m doesn't mean you are destined for anywhere [least of
all a singularity].
But when r < 2m, he appears to think it is a non-physical solution
because there is a transition from time-like to space-like coordinates
[time and space swap roles - moving forward in time within r = 2m means
you are moving in space].
His entire argument seems to be "r > 2m is physical, r < 2m is not
because the metric does funky things!". He does not address what
happens to a neutron star of say, 2 solar masses.
If, according to him, a black hole can NOT form there must be something
preventing a supermassive neutron star [by supermassive I mean a
neutron star that has a mass that is larger than the Chandreskahar
limit] from receding beyond its' own event horizon. He offers no
explanation, which does not satisfy me because the entire reason black
holes have any link to reality is through the death of a star.
I would think that with the amount of people who dislike black holes on
any level, he would find someone to publish him. The best he seems to
have is an endorsement for the arXiv, which concerns me.
Place two papers side by side and wipe your mind of the ability to
understand them. One is published ...somewhere... and the other sits on
the preprint server without being published. Which one will you trust,
even if the trust only goes as far as your ability to throw it?
How are you at math and tensors?
The word undergrad comes to mind. Give me the PDE set that falls out of
Einstein's equations and I ...might... be able to tell you something,
but I can't tell you if you have derived them correctly.
I side with the majority opinion on black holes because it is the
majority opinion, and black holes fit a nice observed cosmic niche.
More to the point, I can't reproduce the derivation of any solution to
Einstein's equations except by rote. I don't like that but I can't do
anything about it for at least another year. [Math is hard, hurr]
BTW, Loinger's interpretation of Schwarzschild's that says black holes
do not exist is not the same thing as saying "black holes do not exist"
because there are other solutions of Einstein's field equations [Kerr
comes to mind] that yield a black hole. Nor is it the same thing as
saying that "Schwarzschild says black holes do not exist".
Ken
...
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| User: "Ken S. Tucker" |
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| Title: Re: GR -> Black Holes Can't Form... Take 2 |
05 Feb 2005 02:11:02 AM |
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Eric Gisse wrote:
Ken S. Tucker wrote:
Eric Gisse wrote:
Ken S. Tucker wrote:
Eric,
Schwarzchild, Einstein, Weinberg, Bergmann, Lottinger and
me Tucker, find BH's impossible. If astronomers can explain
why those theoreticians are all wrong why haven't they.
I happen to understand GR, it's possible we made a common
error, what was it?
Ken
Schwarzschild? No way I will believe that without a citation.
Especially considering the rather...short...period between his
publishing of his solution and his untimely death in the trenches
of
WW1.
I mispelled, Lottinger should be LOINGER.
He has posted a translation of Schwarzchild's
original work in arXiv. I usually have the
paper handy but my temp office is a mess.
A search will turn it up, we can discuss that
if you want, instead of Bergmann's text.
http://xxx.lanl.gov/PS_cache/physics/pdf/0402/0402088.pdf
Thanks Eric, see also physics/9905030
that's the one I was thinking of, Schwarz.(KS)
puts the singularity at the origin in his
original solution.
This appears to be the crux of his argument:
"The HDW-form is physically valid only for r > 2m, because within the
spatial surface r = 2m (a singular locus) the time co-ordinate takes
the role of the radial co-ordinate, and vice versa (and therefore ds2
loses its essential property of physical appropriateness) and the
solution becomes non-static."
It appears that he is saying beyond r = 2m the Schwarzchild solution
[I
never heard it called HDW until today...*shrug*] is a physical one
and
thus acceptable. I have always understood this to mean the
coordinates
outside the event-horizon are time-like - moving along a geodesic
outside of r = 2m doesn't mean you are destined for anywhere [least
of
all a singularity].
But when r < 2m, he appears to think it is a non-physical solution
because there is a transition from time-like to space-like
coordinates
[time and space swap roles - moving forward in time within r = 2m
means
you are moving in space].
His entire argument seems to be "r > 2m is physical, r < 2m is not
because the metric does funky things!".
Ha, no, I think it's because "r" is Euclidian,
and pythagorean, that definition of radius is
modified by GR in g-fields. KS uses R in his
solution. I'll give my understanding if you
want after you look over the original KS
solution.
He does not address what
happens to a neutron star of say, 2 solar masses.
So what?
If, according to him, a black hole can NOT form there must be
something
preventing a supermassive neutron star [by supermassive I mean a
neutron star that has a mass that is larger than the Chandreskahar
limit] from receding beyond its' own event horizon. He offers no
explanation, which does not satisfy me because the entire reason
black
holes have any link to reality is through the death of a star.
Einstein suggests, and I agree, that baryons,
under sufficient pressure decay to gamma-rays.
I would think that with the amount of people who dislike black holes
on
any level,
he would find someone to publish him. The best he seems to
have is an endorsement for the arXiv, which concerns me.
Then go to the original KS solution and Einstein.
I certainly question credentials, that's why I
can provide at least 5 references, and my own
understanding, that's up to you, if trust is
what you need.
Place two papers side by side and wipe your mind of the ability to
understand them. One is published ...somewhere... and the other sits
on
the preprint server without being published. Which one will you
trust,
even if the trust only goes as far as your ability to throw it?
Damn, I'm not converting GR into a popularity
contest, I'd win based on my good looks!
How are you at math and tensors?
The word undergrad comes to mind. Give me the PDE set that falls out
of
Einstein's equations and I ...might... be able to tell you something,
but I can't tell you if you have derived them correctly.
I side with the majority opinion on black holes because it is the
majority opinion, and black holes fit a nice observed cosmic niche.
Democracy, hmmm so Republican's decide on BH's.
More to the point, I can't reproduce the derivation of any solution
to
Einstein's equations except by rote. I don't like that but I can't do
anything about it for at least another year. [Math is hard, hurr]
BTW, Loinger's interpretation of Schwarzschild's that says black
holes
do not exist is not the same thing as saying "black holes do not
exist"
because there are other solutions of Einstein's field equations [Kerr
comes to mind] that yield a black hole. Nor is it the same thing as
saying that "Schwarzschild says black holes do not exist".
Let's do science not sematics.
Ken
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| User: "Eric Gisse" |
|
| Title: Re: GR -> Black Holes Can't Form... Take 2 |
05 Feb 2005 05:31:18 AM |
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Ken S. Tucker wrote:
[snip]
This appears to be the crux of his argument:
"The HDW-form is physically valid only for r > 2m, because within
the
spatial surface r = 2m (a singular locus) the time co-ordinate
takes
the role of the radial co-ordinate, and vice versa (and therefore
ds2
loses its essential property of physical appropriateness) and the
solution becomes non-static."
It appears that he is saying beyond r = 2m the Schwarzchild
solution
[I
never heard it called HDW until today...*shrug*] is a physical one
and
thus acceptable. I have always understood this to mean the
coordinates
outside the event-horizon are time-like - moving along a geodesic
outside of r = 2m doesn't mean you are destined for anywhere [least
of
all a singularity].
But when r < 2m, he appears to think it is a non-physical solution
because there is a transition from time-like to space-like
coordinates
[time and space swap roles - moving forward in time within r = 2m
means
you are moving in space].
His entire argument seems to be "r > 2m is physical, r < 2m is not
because the metric does funky things!".
Ha, no, I think it's because "r" is Euclidian,
and pythagorean, that definition of radius is
modified by GR in g-fields. KS uses R in his
solution. I'll give my understanding if you
want after you look over the original KS
solution.
How is the use of "r" as a measure of distance from the mass a problem?
You have to measure SOMEHOW, and spherical coordinates were used. If
using "r" as a measurment of distance is a problem in this case, it
will be a problem in a lot of other cases where a radial coordinate is
used - because as you said, the classical definition of radius is
modified by GR in gravitational fields.
His argument really seems to be summed up by two ideas: The
Schwarzschild solution does nasty things with r <= 2m and is somehow
unapplicable to reality. Also, "I was motivated by a simple
consideration: all the Great Spirits who
founded and developed GR thought that the notion of BH belongs to
science
fiction". He is working from a preconcieved notion!
He has a particular bias against black holes, and it seeps into his
writing. He does not consider any of the other metrics. When he says
that black holes do not exist, he bases his entire opinion on his
interpretation of the Schwarzschild metric and does not appear to
consider even the case of changed coordinates in the metric which
remove the singularity at r = 2m which he fixates on so fondly.
Read his writing as if it was Androcles. Hunt for the bias. His bias
leaks through even in his references list.
He does not address what
happens to a neutron star of say, 2 solar masses.
So what?
The only reason black holes were thought to even be possible is through
an overly large neutron star being unable to resist gravity.
If, according to him, a black hole can NOT form there must be
something
preventing a supermassive neutron star [by supermassive I mean a
neutron star that has a mass that is larger than the Chandreskahar
limit] from receding beyond its' own event horizon. He offers no
explanation, which does not satisfy me because the entire reason
black
holes have any link to reality is through the death of a star.
Einstein suggests, and I agree, that baryons,
under sufficient pressure decay to gamma-rays.
You'll have to explain that one a bit. I don't want to speculate on
what exactly you mean by that. I would be surprised if there was a
stable configuration of matter between "neutron star" and "black hole".
I would think that with the amount of people who dislike black
holes
on
any level,
he would find someone to publish him. The best he seems to
have is an endorsement for the arXiv, which concerns me.
Then go to the original KS solution and Einstein.
Singular at r = 0 and 2m, but a change of coordinates removes the r =
2m singularity. The Schwarzschild metric isn't the only one out there.
I certainly question credentials, that's why I
can provide at least 5 references, and my own
understanding, that's up to you, if trust is
what you need.
Place two papers side by side and wipe your mind of the ability to
understand them. One is published ...somewhere... and the other
sits
on
the preprint server without being published. Which one will you
trust,
even if the trust only goes as far as your ability to throw it?
Damn, I'm not converting GR into a popularity
contest, I'd win based on my good looks!
I'm simply trying to justify my position.
How are you at math and tensors?
The word undergrad comes to mind. Give me the PDE set that falls
out
of
Einstein's equations and I ...might... be able to tell you
something,
but I can't tell you if you have derived them correctly.
I side with the majority opinion on black holes because it is the
majority opinion, and black holes fit a nice observed cosmic niche.
Democracy, hmmm so Republican's decide on BH's.
Thats nice. You know what I am trying to say.
More to the point, I can't reproduce the derivation of any solution
to
Einstein's equations except by rote. I don't like that but I can't
do
anything about it for at least another year. [Math is hard, hurr]
BTW, Loinger's interpretation of Schwarzschild's that says black
holes
do not exist is not the same thing as saying "black holes do not
exist"
because there are other solutions of Einstein's field equations
[Kerr
comes to mind] that yield a black hole. Nor is it the same thing as
saying that "Schwarzschild says black holes do not exist".
Let's do science not sematics.
Ken
Semantics matter sometimes.
.
|
|
|
| User: "Ken S. Tucker" |
|
| Title: Re: GR -> Black Holes Can't Form... Take 2 |
05 Feb 2005 06:07:05 AM |
|
|
Eric Gisse wrote:
Ken S. Tucker wrote:
Eric it's near 4am, me, I'm an insomniac.
....
Ha, no, I think it's because "r" is Euclidian,
and pythagorean, that definition of radius is
modified by GR in g-fields. KS uses R in his
solution. I'll give my understanding if you
want after you look over the original KS
solution.
How is the use of "r" as a measure of distance from the mass a
problem?
Because it's fictious in a g-field.
You have to measure SOMEHOW, and spherical coordinates were used. If
using "r" as a measurment of distance is a problem in this case, it
will be a problem in a lot of other cases where a radial coordinate
is
used - because as you said, the classical definition of radius is
modified by GR in gravitational fields.
Use R = r-2m
then when r=2m, R=0, and the BH can't exist.
His argument really seems to be summed up by two ideas: The
Schwarzschild solution does nasty things with r <= 2m and is somehow
unapplicable to reality. Also, "I was motivated by a simple
consideration: all the Great Spirits who
founded and developed GR thought that the notion of BH belongs to
science
fiction". He is working from a preconcieved notion!
Na, Italian's inject hyperbole, the body of
the work is to be considered.
He has a particular bias against black holes, and it seeps into his
writing. He does not consider any of the other metrics. When he says
that black holes do not exist, he bases his entire opinion on his
interpretation of the Schwarzschild metric and does not appear to
consider even the case of changed coordinates in the metric which
remove the singularity at r = 2m which he fixates on so fondly.
Read his writing as if it was Androcles. Hunt for the bias. His bias
leaks through even in his references list.
No Eric, you're becoming silly, Einstein agrees with
me and Loinger.
He does not address what
happens to a neutron star of say, 2 solar masses.
So what?
The only reason black holes were thought to even be possible is
through
an overly large neutron star being unable to resist gravity.
If, according to him, a black hole can NOT form there must be
something
preventing a supermassive neutron star [by supermassive I mean a
neutron star that has a mass that is larger than the
Chandreskahar
limit] from receding beyond its' own event horizon. He offers no
explanation, which does not satisfy me because the entire reason
black
holes have any link to reality is through the death of a star.
Einstein suggests, and I agree, that baryons,
under sufficient pressure decay to gamma-rays.
You'll have to explain that one a bit. I don't want to speculate on
what exactly you mean by that. I would be surprised if there was a
stable configuration of matter between "neutron star" and "black
hole".
It means ordinary matter falling on a n-star will
liberate gamma rays.
I would think that with the amount of people who dislike black
holes
on
any level,
he would find someone to publish him. The best he seems to
have is an endorsement for the arXiv, which concerns me.
Then go to the original KS solution and Einstein.
Singular at r = 0 and 2m, but a change of coordinates removes the r =
2m singularity. The Schwarzschild metric isn't the only one out
there.
Ok, but you did ask for a citation you got it.
Never heard you say thanks....
I certainly question credentials, that's why I
can provide at least 5 references, and my own
understanding, that's up to you, if trust is
what you need.
Place two papers side by side and wipe your mind of the ability
to
understand them. One is published ...somewhere... and the other
sits
on
the preprint server without being published. Which one will you
trust,
even if the trust only goes as far as your ability to throw it?
Damn, I'm not converting GR into a popularity
contest, I'd win based on my good looks!
I'm simply trying to justify my position.
Good chance you can't do it "simply", as you
say it's tough stuff.
How are you at math and tensors?
The word undergrad comes to mind. Give me the PDE set that falls
out
of
Einstein's equations and I ...might... be able to tell you
something,
but I can't tell you if you have derived them correctly.
I side with the majority opinion on black holes because it is the
majority opinion, and black holes fit a nice observed cosmic
niche.
Democracy, hmmm so Republican's decide on BH's.
Thats nice. You know what I am trying to say.
LOL, let's sneak it into a California referendum!
More to the point, I can't reproduce the derivation of any
solution
to
Einstein's equations except by rote. I don't like that but I
can't
do
anything about it for at least another year. [Math is hard, hurr]
BTW, Loinger's interpretation of Schwarzschild's that says black
holes
do not exist is not the same thing as saying "black holes do not
exist"
because there are other solutions of Einstein's field equations
[Kerr
comes to mind] that yield a black hole. Nor is it the same thing
as
saying that "Schwarzschild says black holes do not exist".
Let's do science not sematics.
Ken
Semantics matter sometimes.
OK, it's been fun
Ken
.
|
|
|
| User: "" |
|
| Title: Re: GR -> Black Holes Can't Form... Take 2 |
07 Feb 2005 04:50:00 PM |
|
|
In sci.physics Ken S. Tucker <dynamics@vianet.on.ca> wrote:
[...]
Use R = r-2m
then when r=2m, R=0, and the BH can't exist.
Here's a proof that Canada doesn't exist. Choose a north-south
coordinate z, with z=0 at the US-Canadian border. Now switch
to a coordinate u, with z=-u^2. Since u^2 is nonnegative, z
must be nonpositive. Therefore there can be nothing north of z=0.
This argument is exactly as sensible as yours. It is, in fact,
almost exactly the same. Sure, you can define a new coordinate
R = r-2m. But just calling it R doesn't mean that it has to be
positive, or that R=0 has to be a point.
If you want to know what this coordinate means, you need to look
at the geometry. For example, is R=0 really a point, an "origin"?
The answer can be read off from the Schwarzschild metric with these
coordinates. It is not -- the collection of points R=0 at a fixed
time is a sphere with area 16 pi m^2.
Steve Carlip
.
|
|
|
| User: "Ken S. Tucker" |
|
| Title: Re: GR -> Black Holes Can't Form... Take 2 |
07 Feb 2005 07:17:04 PM |
|
|
wrote:
In sci.physics Ken S. Tucker <dynamics@vianet.on.ca> wrote:
[...]
Use R = r-2m
then when r=2m, R=0, and the BH can't exist.
Here's a proof that Canada doesn't exist. Choose a north-south
coordinate z, with z=0 at the US-Canadian border. Now switch
to a coordinate u, with z=-u^2. Since u^2 is nonnegative, z
must be nonpositive. Therefore there can be nothing north of z=0.
That's a good excuse for skipping school,
until that damn math teacher turned the
globe upside down...
This argument is exactly as sensible as yours. It is, in fact,
almost exactly the same. Sure, you can define a new coordinate
R = r-2m. But just calling it R doesn't mean that it has to be
positive, or that R=0 has to be a point.
If you want to know what this coordinate means, you need to look
at the geometry. For example, is R=0 really a point, an "origin"?
Yes in my understanding. The evidence for this is
the angle of light deflection, which doubles Newtons
due to the spatial contraction. I literally accept
Length = (G/c^4)*Mass, i.e. for the Sun that's 1.47 km.
Then for space only,
R = r - m
R = r - 1.47 km (for Sun)
(r=radius in absense of mass, ie. r^2=x^2+y^2+z^2
holds, but it's only a reference)
defines the spatial field *globally*. I wrote a
sim and tested that, it works, use R=r-2m though,
that's consistent with Weinberg's Eq.(9.2.5),
C ~ c*g_00
where C is the *velocity* of light in a g-field.
The *velocity* is perturbed, relative to a massless
CS, in magnitude and direction, the Shapiro effect
tests the magnitude.
The answer can be read off from the Schwarzschild metric with these
coordinates. It is not -- the collection of points R=0 at a fixed
time is a sphere with area 16 pi m^2.
I suspect an artifact.
I would have no problem considering a
volume of space given by (4/3)*pi*(1.47 km)^3
has the same mass as the Sun, if Einstein's
Mass => Length conversion is true, and then
an area could be calculated, it might be
useful.
Steve Carlip
Regards
Ken S. Tucker
.
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