 |
|
| Science Forum Index » Physics - Research Forum » Einstein's 1939 paper challenging the existence of... |
|
Page 3 of 3 Goto page Previous 1, 2, 3 |
|
| Author |
Message |
| Eric Gisse... |
 Posted: Tue May 26, 2009 6:18 am |
|
|
|
Guest
|
On May 20, 8:06 am, Eric Gisse <jowr... at (no spam) gmail.com> wrote:
[...]
An article on Doeleman's followup study was posted, in which this
arXiv article was referenced: http://arxiv.org/abs/0903.1105
It weaves together a lot of what I have been saying with more
technical details, and some stuff I did not know and/or had not
considered.
I do wish we had a greater grasp of the spin parameter, though. If we
had that, the accretion region's dynamics could be much more cleanly
understood. |
|
|
| Back to top |
|
|
|
| Juan R." González-Álvarez... |
| Posted: Wed May 27, 2009 7:37 am |
|
|
|
Guest
|
Eric Gisse wrote on Tue, 26 May 2009 16:18:33 +0000:
[quote:78872586e8]On May 20, 8:06 am, Eric Gisse <jowr... at (no spam) gmail.com> wrote:
[...]
An article on Doeleman's followup study was posted, in which this
arXiv article was referenced: http://arxiv.org/abs/0903.1105
[/quote:78872586e8]
Doeleman et al. paper do not suport your belief that black holes have
been showed to exist.
http://www.nature.com/nature/journal/v455/n7209/abs/nature07245.html
In their paper they talk about "black holes candidate" and about the
"presumed black hole", because they did not show that you said.
Neither the above preprint support your belief that black holes have
been showed to exist. From authors conclusion:
"As a result, our conclusions may be applied more generally to all
gravitational theories that admit notions of energy conservation in
the test-particle limit. Specifically, these include all geometric
gravitational theories that admit stationary solutions, including
all of the f (R) theories and black hole alternatives that exist
within the context of GR. As a consequence, we cannot yet say that
Sgr A* is described by a GR black hole despite being able to conclude
that a horizon must exist."
Moreover, their claim they observed a horizon is open to criticism.
It seems they showed the existence of a "blackbody" surface:
"Consequently, high-redshift surfaces present a perverse realization
of the canonical pin-hole cavity, becoming ideal blackbodies as z
goes to infnity (Broderick & Narayan 2006). For a Schwarzschild
spacetime this is shown in Fig. 1; however this behavior is generic
to spherically symmetric spacetimes. Thus if the system has
sufficient time to have reached steady state, it must be a
blackbody."
And compare this with other models, as neutron stars, in the
section "Observational limits upon the existence of horizons"
"The primary astrophysical importance of a horizon is that the
gravitational binding energy liberated by material as it accretes
can be advected into the black hole without any further observational
consequence. This is very different from accretion onto other compact
objects, e.g., neutron stars, in which this liberated energy
ultimately must be emitted by the stellar surface. Importantly, this
argument is not dependent upon the particulars of the compact object.
Any object powered by accretion, whose surface is visible from the
external universe, should show evidence of surface radiation. We will
use this fact to rule out the possibility that accreted material in
Sgr A* settles in a region visible to outside observers, and in doing
so make the argument that a horizon /must/ exist.
The work is interesting because the quantum theory of gravitational
field (not GR) predicts existence of condensed objects (several
millions of solar masses) without singularities horizon but with
intrinsic magnetic field, and with the "high-redshift surfaces" that
authors observed (and interpreted as horizon).
However, the black hole model explanation of the low luminosity
phase is based in ADAF(RIAF) hypotesis, which is not compatible with
the observed magnetic fields (see references given in another message
in this same thread).
The quantum theory of gravitational field do not use ADAF(RIAF) and
explain the low luminosity phase by the "propeller effect" of the
magnetic field.. Thus it seems this model has better observational
support and is free of difficulties as singularities.
--
http://www.canonicalscience.org/
Usenet Guidelines:
http://www.canonicalscience.org/en/miscellaneouszone/guidelines.html |
|
|
| Back to top |
|
|
|
| Eric Gisse... |
| Posted: Thu May 28, 2009 6:53 am |
|
|
|
Guest
|
On May 27, 9:37 am, "Juan R." González-Álvarez
<juanREM... at (no spam) canonicalscience.com> wrote:
[quote:a7acd103a1]Eric Gisse wrote on Tue, 26 May 2009 16:18:33 +0000:
On May 20, 8:06 am, Eric Gisse <jowr... at (no spam) gmail.com> wrote:
[...]
An article on Doeleman's followup study was posted, in which this
arXiv article was referenced:http://arxiv.org/abs/0903.1105
Doeleman et al. paper do not suport your belief that black holes have
been showed to exist.
[/quote:a7acd103a1]
Actually, it does. Read the paper.
I continue to wonder where the goal post lies for black holes. How
strong must the evidence be?
[quote:a7acd103a1]
http://www.nature.com/nature/journal/v455/n7209/abs/nature07245.html
[/quote:a7acd103a1]
Yes, I know. I gave it to you.
[quote:a7acd103a1]
In their paper they talk about "black holes candidate" and about the
"presumed black hole", because they did not show that you said.
[/quote:a7acd103a1]
You are relying on overly conservative but intrinstic scientific doubt
to make your case. Can you really not do better than that?
[quote:a7acd103a1]
Neither the above preprint support your belief that black holes have
been showed to exist. From authors conclusion:
[/quote:a7acd103a1]
Holy crap. What does it take to make you reconsider?
[quote:a7acd103a1]
"As a result, our conclusions may be applied more generally to all
gravitational theories that admit notions of energy conservation in
the test-particle limit. Specifically, these include all geometric
gravitational theories that admit stationary solutions, including
all of the f (R) theories and black hole alternatives that exist
within the context of GR. As a consequence, we cannot yet say that
Sgr A* is described by a GR black hole despite being able to conclude
that a horizon must exist."
Moreover, their claim they observed a horizon is open to criticism.
[/quote:a7acd103a1]
Regardless, they made a strong case for the existence of a horizon.
[quote:a7acd103a1]It seems they showed the existence of a "blackbody" surface:
"Consequently, high-redshift surfaces present a perverse realization
of the canonical pin-hole cavity, becoming ideal blackbodies as z
goes to infnity (Broderick & Narayan 2006). For a Schwarzschild
spacetime this is shown in Fig. 1; however this behavior is generic
to spherically symmetric spacetimes. Thus if the system has
sufficient time to have reached steady state, it must be a
blackbody."
[/quote:a7acd103a1]
Try reading the whole paper. No such high redshift surface was found.
The surface was, in fact, ruled out because of the near-100%
conversion efficiencies needed and the complete lack of observational
support in the IR spectrum.
[quote:a7acd103a1]
And compare this with other models, as neutron stars, in the
section "Observational limits upon the existence of horizons"
[/quote:a7acd103a1]
Neutron stars have surfaces.
Neutron stars make optical noise when stuff falls on the surface.
Neutron stars are orders of magnitude less compact than what would be
required to explain the goings-on at (no spam) Sgr. A*.
[quote:a7acd103a1]
"The primary astrophysical importance of a horizon is that the
gravitational binding energy liberated by material as it accretes
can be advected into the black hole without any further observational
consequence. This is very different from accretion onto other compact
objects, e.g., neutron stars, in which this liberated energy
ultimately must be emitted by the stellar surface.
[/quote:a7acd103a1]
This is important. You should read this paragraph again.
[quote:a7acd103a1]Importantly, this
argument is not dependent upon the particulars of the compact object.
[/quote:a7acd103a1]
This is also important. The argumet is _independent_ from the
specifics of the alternatives so long as there _is_ an exterior but
highly redshfited surface.
This is why I consider the gravastar / MECO concepts to be ruled out
or at least made fantastically unlikely - without even considering
difficulties intrinstic to the objects themselves.
[quote:a7acd103a1] Any object powered by accretion, whose surface is visible from the
external universe, should show evidence of surface radiation. We will
use this fact to rule out the possibility that accreted material in
Sgr A* settles in a region visible to outside observers, and in doing
so make the argument that a horizon /must/ exist.
The work is interesting because the quantum theory of gravitational
field (not GR) predicts existence of condensed objects (several
millions of solar masses) without singularities horizon but with
intrinsic magnetic field, and with the "high-redshift surfaces" that
authors observed (and interpreted as horizon).
[/quote:a7acd103a1]
You are now relying on a theory of gravitation that _does not exist_
in order to explain observation in order to avoid using classical
general relativity.
If you have an actual reference for this I'd love to see it but the
fact remains you are seriously grasping at straws here.
[quote:a7acd103a1]
However, the black hole model explanation of the low luminosity
phase is based in ADAF(RIAF) hypotesis, which is not compatible with
the observed magnetic fields (see references given in another message
in this same thread).
[/quote:a7acd103a1]
The _inferred_ magnetic fields are not inconsistent with the RIAF
model unless you would like to make the claim that a magnetic field
inside a relativistic plasma is an unusual thing. Plus, if you read
your references, the _inferred_ magnetic fields are based on
assumptions by Robinson, Leiter, etc. _assuming_ the MECO concept is
correct.
The only argument that *could* be made is that highly variable
magnetic fields contradict the assumptions of the RIAF model, however
there is no evidence for that.
[quote:a7acd103a1]
The quantum theory of gravitational field do not use ADAF(RIAF) and
explain the low luminosity phase by the "propeller effect" of the
magnetic field.. Thus it seems this model has better observational
support and is free of difficulties as singularities.
[/quote:a7acd103a1]
We'll see.
[quote:a7acd103a1]
--http://www.canonicalscience.org/
Usenet Guidelines:http://www.canonicalscience.org/en/miscellaneouszone/guidelines.html[/quote:a7acd103a1] |
|
|
| Back to top |
|
|
|
| Juan R." González-Álvarez... |
| Posted: Thu May 28, 2009 11:40 am |
|
|
|
Guest
|
|
| Back to top |
|
|
|
| Juan R." González-Álvarez... |
| Posted: Fri Jun 12, 2009 7:03 am |
|
|
|
Guest
|
Eric Gisse wrote on Thu, 28 May 2009 18:53:52 +0200:
[quote:0c86981ba5]On May 27, 9:37Â am, "Juan R." González-Álvarez
juanREM... at (no spam) canonicalscience.com> wrote:
Eric Gisse wrote on Tue, 26 May 2009 16:18:33 +0000:
On May 20, 8:06 am, Eric Gisse <jowr... at (no spam) gmail.com> wrote:
[...]
An article on Doeleman's followup study was posted, in which this
arXiv article was referenced:http://arxiv.org/abs/0903.1105
Doeleman et al. paper do not suport your belief that black holes have
been showed to exist.
[/quote:0c86981ba5]
(...)
[quote:0c86981ba5]http://www.nature.com/nature/journal/v455/n7209/abs/nature07245.html
Yes, I know. I gave it to you.
[/quote:0c86981ba5]
But you continue to cite it as if were supporting your own claims. Below
again you disagree with authors are really saying.
[quote:0c86981ba5]In their paper they talk about "black holes candidate" and about the
"presumed black hole", because they did not show that you said.
You are relying on overly conservative but intrinstic scientific doubt
to make your case. Can you really not do better than that?
[/quote:0c86981ba5]
Your misunderstand of the paper and your fail to grasp *why* the authors
continue to use the terms "black holes candidate" and "presumed black
hole" in their work, are not valid excuses for your continued pretension
this reference is supporting your own ideas.
I talk about black hole candidates, they talk about black hole candidates.
We disagree with you.
[quote:0c86981ba5]Neither the above preprint support your belief that black holes have
been showed to exist. From authors conclusion:
Holy crap. What does it take to make you reconsider?
[/quote:0c86981ba5]
Again you dishonestly pretended to cite a preprint as if authors were
supporting your rants and beliefs, and when I have pointed it is just the
contrary and when I have quoted author conclusions. You *snip* them and
qualify as "holy crap".
If you do not agree with they writing about how "black hole alternatives"
explain the same data or if you do not like their claim "we cannot yet say
that Sgr A* is described by a GR black hole" because contradicts your
pretension, that is your problem.
(...)
[quote:0c86981ba5]It seems they showed the existence of a "blackbody" surface:
"Consequently, high-redshift surfaces present a perverse
realization of the canonical pin-hole cavity, becoming ideal
blackbodies as z goes to infnity (Broderick & Narayan 2006). For a
Schwarzschild spacetime this is shown in Fig. 1; however this
behavior is generic to spherically symmetric spacetimes. Thus if the
system has sufficient time to have reached steady state, it must be a
blackbody."
Try reading the whole paper. No such high redshift surface was found.
The surface was, in fact, ruled out because of the near-100% conversion
efficiencies needed and the complete lack of observational support in
the IR spectrum.
[/quote:0c86981ba5]
They studied a surface (yes subindex "surf" in expressions 4, 5, 9, 10...
and in figures 4 and 5... mean "surface" even if you did not noticed) and
found that surface behaves like they named a blackbody surface.
They also note in several parts of the preprint that a very high z surface
is equivalent to a perfect blackbody surface, e.g. in figure 1, in page
3...
(...)
(rest sniped)
--
http://www.canonicalscience.org/
Usenet Guidelines:
http://www.canonicalscience.org/en/miscellaneouszone/guidelines.html |
|
|
| Back to top |
|
|
|
|
|
All times are GMT - 5 Hours
The time now is Thu Mar 18, 2010 1:44 am
|
|