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decraig

Drunk on Black Holes

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"The black hole at the center of the galaxy..." is an oft repeated phrase on the science channels.

 

1) The cited evidence for this is the motion of stars at the center of the galaxy.

 

This evidence is insufficient. An object of highly collapsed matter would have the same effect.

 

How would one distinguish between an incipient back hole and a back hole? In an incipient back hole the bulk of the matter lies outside the surface where the event horizon would form.

 

Can highly collapsed matter exchange Hawking radiation with it's environment?

 

 

2) The Schwarzschild solution having an event horizon is non-physical. The solution stretches over transfinite time. I imagine the same is true of the Kerr solution and the rest. Correct?

 

Should there be a black hole at the center of our galaxy, it would be a primordial black hole, having gained or lost very little mass, and only through Hawking radiation.

 

 

3) The astronomy Gugus of the science channels also like to talk about things crossing the event horizon. Nothing crosses the event horizon to a stationary observer outside a back hole with the exception of virtual particles. To an Earthly observer, things don't cross the event horizon. Any objections?

 

 

4) We could imagine the Earth, some day, falling through the event horizon, the coordinates singularity defined by an outside stationary observer. Then we would see things falling through with us. But this cannot happen. The Earth would reach the horizon in transfinite number of seconds as measured by an outside observer. This gives our black hole an infinite amount of time to radiate into an expanded, very cold universe and vanish before the Earth, or any would-be adventurer crossed the horizon.

 

 

[Edit:] One more thing: What is the theoretical support for primordial black holes and what quality?

Edited by decraig

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Can highly collapsed matter exchange Hawking radiation with it's environment?

 

 

Hawking radiation is theoretical physics. Not confirmed by experimental evidence.

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This evidence is insufficient. An object of highly collapsed matter would have the same effect.

Nothing we know of but a black hole can be that dense to explain the motion of these stars.

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1) The cited evidence for this is the motion of stars at the center of the galaxy.

 

This evidence is insufficient.

While we don't have direct evidence, the theory of relativity is well tested and from it and our current knowledge of nature we can infer that black holes are inevitable, we don't know of any reason at all for why they should not form. Our observations match predictions made by our models of black holes and we don't have any other explanation for the Sagittarius A* region in our Milky Way galaxy.

 

"Currently, the best evidence for a supermassive black hole comes from studying the proper motion of stars near the center of our own Milky Way. Since 1995 astronomers have tracked the motion of 90 stars in a region called Sagittarius A*. By fitting their motion to Keplerian orbits they were able to infer in 1998 that 2.6 million solar masses must be contained in a volume with a radius of 0.02 lightyears. Since then one of the starscalled S2has completed a full orbit. From the orbital data they were able to place better constraints on the mass and size of the object causing the orbital motion of stars in the Sagittarius A* region, finding that there is a spherical mass of 4.3 million solar masses contained within a radius of less than 0.002 lightyears. While this is more than 3000 times the Schwarzschild radius corresponding to that mass, it is at least consistent with the central object being a supermassive black hole, and no "realistic cluster [of stars] is physically tenable"."

http://en.wikipedia.org/wiki/Black_hole#Galactic_nuclei

 

 

An object of highly collapsed matter would have the same effect.

How would the material in such a highly collapsed object maintain its shape against the enormous internal pressure from its own gravity?

 

"The TolmanOppenheimerVolkoff limit (or TOV limit) is an upper bound to the mass of stars composed of neutron-degenerate matter (i.e. neutron stars). The TOV limit is analogous to the Chandrasekhar limit for white dwarf stars. It is approximately 1.5 to 3.0 solar masses, corresponding to an original stellar mass of 15 to 20 solar masses.

 

The limit was first computed by J. Robert Oppenheimer and George Volkoff in 1939, using the work of Richard Chace Tolman. Oppenheimer and Volkoff assumed that the neutrons in a neutron star formed a degenerate cold Fermi gas. This leads to a limiting mass of approximately 0.7 solar masses. Modern estimates range from approximately 1.5 to 3.0 solar masses. The uncertainty in the value reflects the fact that the equations of state for extremely dense matter are not well known. The mass of PSR J16142230, 1.97±0.04 solar masses puts a lower bound on TOV limit.

 

In a neutron star less massive than the limit, the weight of the star is balanced by short-range repulsive neutron-neutron interactions mediated by the strong force and also by the quantum degeneracy pressure of neutrons, preventing collapse. If its mass is above the limit, the star will collapse to some denser form. It could form a black hole, or change composition and be supported in some other way (for example, by quark degeneracy pressure if it becomes a quark star). Because the properties of hypothetical more exotic forms of degenerate matter are even more poorly known than those of neutron-degenerate matter, most astrophysicists assume, in the absence of evidence to the contrary, that a neutron star above the limit collapses directly into a black hole."

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

 

 

How would one distinguish between an incipient back hole and a back hole? In an incipient back hole the bulk of the matter lies outside the surface where the event horizon would form.

According to our understanding a black hole forms from a huge star collapsing under its own weight, which implies that the main source of gravity would lie in the center, inside an outward growing event horizon.

 

"Gravitational collapse occurs when an object's internal pressure is insufficient to resist the object's own gravity. For stars this usually occurs either because a star has too little "fuel" left to maintain its temperature through stellar nucleosynthesis, or because a star that would have been stable receives extra matter in a way that does not raise its core temperature. In either case the star's temperature is no longer high enough to prevent it from collapsing under its own weight. The collapse may be stopped by the degeneracy pressure of the star's constituents, condensing the matter in an exotic denser state. The result is one of the various types of compact star. The type of compact star formed depends on the mass of the remnantthe matter left over after the outer layers have been blown away, such from a supernova explosion or by pulsations leading to a planetary nebula. Note that this mass can be substantially less than the original starremnants exceeding 5 solar masses are produced by stars that were over 20 solar masses before the collapse.

 

If the mass of the remnant exceeds about 34 solar masses (the TolmanOppenheimerVolkoff limit)either because the original star was very heavy or because the remnant collected additional mass through accretion of mattereven the degeneracy pressure of neutrons is insufficient to stop the collapse. No known mechanism (except possibly quark degeneracy pressure, see quark star) is powerful enough to stop the implosion and the object will inevitably collapse to form a black hole."

http://en.wikipedia.org/wiki/Black_hole#Gravitational_collapse

 

 

Can highly collapsed matter exchange Hawking radiation with it's environment?

From my simple understanding, Hawking radiation requires an event horizon with the ability for particles to fall through it.

 

"A slightly more precise, but still much simplified, view of the process is that vacuum fluctuations cause a particle-antiparticle pair to appear close to the event horizon of a black hole. One of the pair falls into the black hole whilst the other escapes. In order to preserve total energy, the particle that fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process, the black hole loses mass, and, to an outside observer, it would appear that the black hole has just emitted a particle.

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

 

 

2) The Schwarzschild solution having an event horizon is non-physical. The solution stretches over transfinite time. I imagine the same is true of the Kerr solution and the rest. Correct?

There are other solutions showing that the singularity for the Schwarzschild solution at the event horizon is an illusion.

 

"In 1924 Arthur Eddington produced the first coordinate transformation (EddingtonFinkelstein coordinates) that showed that the singularity at r = rs was a coordinate artifact, although he seems to have been unaware of the significance of this discovery. Later, in 1932, Georges Lemaître gave a different coordinate transformation (Lemaître coordinates) to the same effect and was the first to recognize that this implied that the singularity at r = rs was not physical. In 1939 Howard Robertson showed that a free falling observer descending in the Schwarzschild metric would cross the r = rs singularity in a finite amount of proper time even though this would take an infinite amount of time in terms of coordinate time t."

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

Edited by Spyman

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2) The Schwarzschild solution having an event horizon is non-physical. The solution stretches over transfinite time.

 

It is true that the Schwarzschild solution makes a number of simplifying assumptions, such as the black hole being eternal and in an empty space. But the fact that those are only approximations does not invalidate the results. After all, simple ballistics calculations work despite the fact that Newtonian gravity is an approximation.

 

By the way, you might want to look up the word "transfinite"; you keep using that word, I do not think it means what you think it means.

 

 

3) The astronomy Gugus of the science channels also like to talk about things crossing the event horizon. Nothing crosses the event horizon to a stationary observer outside a back hole with the exception of virtual particles. To an Earthly observer, things don't cross the event horizon. Any objections?

 

This just isn't true. You seem to take one bit of a theory (from those "Gugus", whatever that means) and try to use it to disprove another bit of the same theory. Is relativity that inconsistent? No. And that can be proved (because it is math not science.)

 

An object will fall through the event horizon in finite proper time. Surprisingly, it will also be seen to disappear in finite time, even by a distant observer. The idea that matter is "stuck" just outside the event horizon is a fallacy created by poor journalism.

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Nothing we know of but a black hole can be that dense to explain the motion of these stars.

I proffered an incipient black hole as such an object.

http://arxiv.org/abs/gr-qc/0609024

 

 

It is true that the Schwarzschild solution makes a number of simplifying assumptions, such as the black hole being eternal and in an empty space. But the fact that those are only approximations does not invalidate the results. After all, simple ballistics calculations work despite the fact that Newtonian gravity is an approximation.

 

By the way, you might want to look up the word "transfinite"; you keep using that word, I do not think it means what you think it means.

 

 

This just isn't true. You seem to take one bit of a theory (from those "Gugus", whatever that means) and try to use it to disprove another bit of the same theory. Is relativity that inconsistent? No. And that can be proved (because it is math not science.)

 

An object will fall through the event horizon in finite proper time. Surprisingly, it will also be seen to disappear in finite time, even by a distant observer. The idea that matter is "stuck" just outside the event horizon is a fallacy created by poor journalism.

 

You should know the distinction between a mathematical model, and physical realisability.

 

 

I have made several points, one not necessarily supporting another. This is something you seem to have read into what I have written.

 

 

It is not I who am making a prediction of a galactic center black hole. In the spirit of scientific fairness the burden of proof really falls upon those making extraordinary claims.

 

I, as yet, remain unconvinced by the arguments put forward on this thread.

Edited by decraig

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It is not I who am making a prediction of a galactic center black hole. In the spirit of scientific fairness the burden of proof really falls upon those making extraordinary claims.

 

I, as yet, remain unconvinced by the arguments put forward on this thread.

Good for you! There is nothing wrong with a sceptical view - just don't forget that incipient black holes that takes an infinite time to form and other speculative non black hole models are more extraordinary and have even less evidence than the standard black hole model.

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I proffered an incipient black hole as such an object.

http://arxiv.org/abs/gr-qc/0609024

I am not so familiar with these non-singular black holes. I am not sure how they would look different to standard black holes for the case at hand.

 

Also, as far as I know, it is not known if such non-singular black holes are stale.

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^stable.

 

Although now I am wondering how a fresh black hole would taste. happy.png

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What besides a black hole can create polar jets at the center of an active galaxy?

Edited by Airbrush

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Good for you! There is nothing wrong with a sceptical view - just don't forget that incipient black holes that takes an infinite time to form and other speculative non black hole models are more extraordinary and have even less evidence than the standard black hole model.

 

Ok... An incipient back hole is no more speculative than a back hole. Less, it seems, not requiring the central singularity of a black hole. I don't know if you intended to include this under the adjective 'speculative' or not.

 

The evidence in support of incipient back holes is the very evidence in support of a galactic centered black hole.

I am not so familiar with these non-singular black holes. I am not sure how they would look different to standard black holes for the case at hand.

 

Also, as far as I know, it is not known if such non-singular black holes are stale.

 

To be sure, these are not black holes, but might become black holes.

 

After some reflection, I think there may be a way (within the ground rules: relativity theory, particle tunneling, and thermal dynamic) for this to happen. I'm going to wait and see if anyone can spot it.

 

But let me ask you something. If I hadn't given this class of objects a name, and pointed to an ArXiv article that also used that name, would you have dismissed me as blathering? This is what I was up against before someone came up with a name I could use.

Edited by decraig

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Its more than a little difficult to comment on these attacks for me, at this time. (And I won't bother with the spell checker.) There seems to be some human demand for the fantasmagorical that drives various demands for recognitiion of some ideas, no matter how ill founded or ill conceived.

 

I will respond to various frture attacks as I can, and find interesting.

 

I suggest you know the subject matter better than a couple 4 years of relativity or you may not fair w

I would suggest not listening to the mongers without a speculative ear.

Edited by decraig

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To be sure, these are not black holes, but might become black holes.

If they have an event horizon then I would be happy to call such object black holes even if there are no singularities inside this horizon. Otherwise it is not clear at all why the term non-singular black hole would be used at all in this context.

 

I have no idea if there is some obvious observational tests here to distinguish standard black holes from non-singular ones. That said, no-one really believes that there are singularities inside the event horizon of a black hole. It is expected that quantum effects would regulate these.

 

But let me ask you something. If I hadn't given this class of objects a name, and pointed to an ArXiv article that also used that name, would you have dismissed me as blathering?

Vague is what I would have said.

Its more than a little difficult to comment on these attacks for me..

Whatever happens please don't confuse any attacks on ideas your put forward or support with attacks on you personally. Having your ideas scrutinized and sometimes poo-pooed is part of science and something you get used to.

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I proffered an incipient black hole as such an object.

http://arxiv.org/abs/gr-qc/0609024

 

Interesting, thanks. I hadn't come across that before. However, one paper on a subject that attempts to combine quantum theory and GR (still a problematical area) is not completely convincing. It will be interesting to see where this goes.

 

 

You should know the distinction between a mathematical model, and physical realisability.

Indeed, as I work with models of reality every day. (I'm not quite sure what your point is though.)

And I won't bother with the spell checker.

 

Perhaps I won't bother reading what you have to say, if you can't be bothered to take any care in writing it.

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If they have an event horizon then I would be happy to call such object black holes even if there are no singularities inside this horizon. Otherwise it is not clear at all why the term non-singular black hole would be used at all in this context.

 

I have no idea if there is some obvious observational tests here to distinguish standard black holes from non-singular ones. That said, no-one really believes that there are singularities inside the event horizon of a black hole. It is expected that quantum effects would regulate these.

 

 

Vague is what I would have said.

 

Whatever happens please don't confuse any attacks on ideas your put forward or support with attacks on you personally. Having your ideas scrutinized and sometimes poo-pooed is part of science and something you get used to.

 

 

OK. fair enough. Let's start from the beginning.

 

I'm not publishing, im just perpetually irritated by what I consider to be outlandish unsubstanciable claims.

 

To get the jist of the whole problem, you must understand that there is coordoninate sigularyity at the surface identified as the event horizon'. This mean that the Jacobian metricc is all jacked up, and thing go to infinity in one direction and the ratio of coordinate displacements tend toward zero in the other.

 

This is a very bothersome boundry. ....................................But what if nature precludeds it.

 

In other words, what if all the fancy equations that have all the easy science geeks jacked up about are pretty and shiny but are not physically realizable?

 

What is various processes are theoretially permissible but require infinite time. How woud your mathetical foralsisms stack up not

 

(to be fair, I've read your profile. I will not publish my own---sorry)

 

Interesting, thanks. I hadn't come across that before. However, one paper on a subject that attempts to combine quantum theory and GR (still a problematical area) is not completely convincing. It will be interesting to see where this goes.

 

Indeed, as I work with models of reality every day. (I'm not quite sure what your point is though.)

 

Perhaps I won't bother reading what you have to say, if you can't be bothered to take any care in writing it.

Edited by decraig

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To get the jist of the whole problem, you must understand that there is coordoninate sigularyity at the surface identified as the event horizon'.

 

But doesn't that mean that the singularity can be removed if you choose different coordinates?

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But doesn't that mean that the singularity can be removed if you choose different coordinates?

i4

Of course. Given an acceleraed coordinant system there is no sigularity. It could be over the event horizon in the accelerated frame. This is one of the reasons (thought relatively minor), it is so difficult so make true statements about black holes (within the context of general relativity, of course).

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An incipient back hole is no more speculative than a back hole.

The scientific consensus don't agree with you, the standard black hole model is a well established part of mainstream physics.

 

 

Less, it seems, not requiring the central singularity of a black hole.

I consider the singularity to be a likely sign of breakdown in the standard model and think that a working theory of quantum gravity will change this, however it's very probable that the standard model will still be a good approximation, far down inside a remaining event horizon feature.

 

 

I don't know if you intended to include this under the adjective 'speculative' or not.

Well, I am not a native english speaker so my grammar might be flawed, I am sorry if this is causing you trouble to understand me. I meant that alternative models are MORE speculative than the standard model. If you want to interpret that as I said the standard model is speculative, then feel free to go ahead and do so, they are all models and not the real thing, none of them are 100 percent certain to remain true forever.

 

 

The evidence in support of incipient back holes is the very evidence in support of a galactic centered black hole.

Which according to your own words in the OP are "insufficient", if you want to replace the standard model with something more complicated, it is not enough to bring the same evidence, (which on top of everything you yourself think is lacking), you need to bring better evidence or a repeatable test able to discern between them by ruling one model out.

 

You have not put forward convincible arguments that the incipient black hole model is more than a viable but still only an alternative model.

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Ok... An incipient back hole is no more speculative than a back hole. Less, it seems, not requiring the central singularity of a black hole.

 

the black hole (as in, event horizon) doesn't require a central singularity. They both emerge from the same theory; but that is believed to be incomplete under the extreme conditions near the singularity (theory of quantum gravity required, probably).

 

There is at least one theory that describes black holes (with event horizon) without a central singularity: http://researchnews.osu.edu/archive/fuzzball.htm

 

This also claims to address the information paradox.

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G00d grief!!!!!!!!!!!!!!!!!!!!!

 

I should never have started this frikin thread.

 

Those who have an piss ant's education in relativity beyond the special theory, raise your hands.

 

Those who don't, but are in love with black holes, can count themselves among the faithful, unthinking followers of authority.

 

 

 

 

Do you really want to understand the mathematical underpinnings of general relatvity?

No one will care.


 

the black hole (as in, event horizon) doesn't require a central singularity. They both emerge from the same theory; but that is believed to be incomplete under the extreme conditions near the singularity (theory of quantum gravity required, probably).

 

There is at least one theory that describes black holes (with event horizon) without a central singularity: http://researchnews.osu.edu/archive/fuzzball.htm

 

This also claims to address the information paradox.

Is this the naked singularity requiring infinite energy density, or have you got something meaninful?


What besides a black hole can create polar jets at the center of an active galaxy?

 

This is a very good point Airbrush. I've wondered also.

 

If you could instruct me how black holes could produce jets, and not incipients produce jets, I would appreciate it

 

 

A

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To get the jist of the whole problem, you must understand that there is coordoninate sigularyity at the surface identified as the event horizon'.

Coordinate singularities are no problem here. They are just due to a poor choice of coordinate system for the problem at hand.

 

It is the singularity at the centre of the black hole hidden behind the horizon that is more problematic.

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Is this the naked singularity requiring infinite energy density, or have you got something meaninful?

 

No, as I said, it gets rid of the singularity (and therefore infinite density). It is speculative, currently, but so is the incipient black hole idea.

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G00d grief!!!!!!!!!!!!!!!!!!!!!

 

I should never have started this frikin thread.

 

Those who have an piss ant's education in relativity beyond the special theory, raise your hands.

 

Those who don't, but are in love with black holes, can count themselves among the faithful, unthinking followers of authority.

So do you consider everyone, who don't agree with you that mainstream science are making outlandish unsubstantial claims with the standard black hole model, to be faithful black hole lovers, unthinking followers of authority and without a piss ant's education in relativity beyond the special theory or was that rant aimed at me personally?

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Maybe you will lead a revolution in understanding black holes, but Wiki is not ready for it.

 

"...Such research has attracted much media attention,[5] as black holes have long captured the imagination of both scientists and the public for both their innate simplicity and mysteriousness. The recent theoretical results have therefore undergone much scrutiny and most of them are now ruled out by theoretical studies. For example several alternative black hole models were shown to be unstable in extremely fast rotation,[6] which, by conservation of angular momentum, would be a not unusual physical scenario for a collapsed star (see pulsar). Nevertheless the existence of a stable model of a nonsingular black hole is still an open question."

 

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

 

Has anyone read and understood what follows? If anyone can explain it to me in English, that would be appreciated!

 

"Observation of Incipient Black Holes and the Information Loss Problem Author(s) Vachaspati, T ; Stojkovic, D ; Krauss, L M Imprint 7 Sep 2006. - 13 p. Subject category General Relativity and Cosmology Abstract (Abridged) We study the (quantum) formation of black holes by spherical domain wall collapse as seen by an asymptotic observer. Using the Wheeler-de Witt equation to describe the collapsing spherical domain wall, we show that the black hole takes an infinite time to form for the asymptotic observer in the quantum theory, just as in the classical treatment. We argue that such observers will therefore see a compact object but never see effects associated with the formation of an event horizon. To explore what signals such observers will see, we study radiation of a scalar quantum field in the collapsing domain wall background. Both the functional Schrodinger approach and an adaptation of Hawking's original calculation indicate that there is radiation from the collapsing domain wall. The radiation may be relevant should gravitational collapse in particle collisions be induced at the LHC if low scale gravity is observed. The radiation is non-thermal, and the total flux radiated diverges when backreaction of the radiation on the collapsing wall is ignored. We discuss the conjecture, based on our analysis, that the domain wall will evaporate completely by non-thermal radiation during the collapse process and never form a black hole or an event horizon. Whether or not there is ``evaporation before formation'' no horizon down which information may be lost forms in any finite time, so that gravitational collapse appears to preserve unitarity. Thus, our findings may resolve the black hole information loss problem. This fact is suggestive of a possible superselection rule separating universes with no initial black hole event horizons from those in which these are initially present."

 

http://cds.cern.ch/record/982547?ln=en


G00d grief!!!!!!!!!!!!!!!!!!!!!

 

I should never have started this frikin thread.

 

A

 

Are you kidding? This is fun.

Edited by Airbrush

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