Blackholes theory maybe incorrect?

[vincentm]

Blackholes theory maybe incorrect??

A controversial alternative to black hole theory has been bolstered by observations of an object in the distant universe, researchers say. If their interpretation is correct, it might mean black holes do not exist and are in fact bizarre and compact balls of plasma called MECOs.
Rudolph Schild of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, led a team that observed a quasar situated 9 billion light years from Earth. A quasar is a very bright, compact object, whose radiation is usually thought to be generated by a giant black hole devouring its surrounding matter.
A rare cosmological coincidence allowed Schild and his colleagues to probe the structure of the quasar in much finer detail than is normally possible. Those details suggest that the central object is not a black hole. "The structure of the quasar is not at all what had been theorised," Schild told New Scientist.

source: http://www.newscientistspace.com/article.ns?id=dn9620&feedId=online-news_rss20

 

[star.torturer]

But i like Black Holes

i can understand where there coming from
good story

 

[Labguy]

But, that site/article also says that:

A well accepted property of black holes is that they cannot sustain a magnetic field of their own. But observations of quasar Q0957+561 indicate that the object powering it does have a magnetic field, Schild's team says.

which hasn't been accepted as the case,AFAIK. We went through this on PF many months (years?) ago and an old Labguy post was:

Virtual Particles from a Black Hole.

One thing that I have noticed, after reading many pages of info on "classical" Hawking Radiation (HR), is that it was conceived and most often described as in its original form as applying to a static, non-rotating, non-accreting and zero-charge black hole (BH) in the original Schwarzschild configuration as a simple mass-only expression of the Schwarzschild Radius (Rs) where Rs = 2GM / c^2. All of the virtual particle pair production scenarios are based on this and require one particle to "fall back" with the other escaping as a real particle causing a mass loss of the BH. So far we have not looked at the possibility of a charged black hole, and have only considered an uncharged, non-rotating black hole. When looking at the entire system, the total energy of the black hole has decreased and therefore, by Einstein's famous relation, the mass must have decreased. This is the process by which black holes radiate, which is commonly known as Hawking radiation.

However, many other research sites and past papers have noted that it is almost impossible to form a BH with no angular momentum (spin). Even the "no hair" statement by Wheeler was that a BH has only three observable properties; (1) mass, (2) angular momentum and (3) charge (usually net zero). But a lot of recent discoveries (and older theories) have added one new property that is (4) magnetic field. At first, it was thought that a magnetic field would only surround a BH that was accreting matter, but Ramon Khanna and Yakov Zeldovich have shown that all black holes will have a magnetic field. There are also the terms "Hawking Process" and “Hawking Effect” appearing, which include/combine the original HR work with work of others such as Thorn and especially Kerr (for spin) and Newman (for charge). The "Kerr-Newman" BH. can be generalized to deal with Spin and Electric Charge. The generalization, called a Kerr-Newman Black Hole, was developed by Kerr (who generalized to add angular momentum J to mass M in 1963) and by Newman (who generalized to add charge e in 1965).

Non-HR Particles

In his paper Generation and Evolution of Magnetic Fields in the Gravitomagnetic Field of a Kerr Black Hole, Ramon Khanna says: "... a rotating black hole can generate magnetic fields in an initially un-magnetized plasma. In axisymmetry a plasma battery can only generate a toroidal magnetic field, but then the coupling of the gravitomagnetic potential with toroidal magnetic fields generates poloidal magnetic fields. Even an axisymmetric self-excited dynamo is theoretically possible, i.e. Cowling's theorem does not hold close to a Kerr black hole. Due to the joint action of gravitomagnetic battery and gravitomagnetic dynamo source term, a rotating black hole will always be surrounded by poloidal and toroidal magnetic fields (probably of low field strength though). The gravitomagnetic dynamo source may generate closed poloidal magnetic field structures around the hole, which will influence the efficiency of the Blandford-Znajek mechanism whereby coupling of the gravitomagnetic potential with a magnetic field results in an electromotive force that drives currents that may extract rotational energy from a black hole.”

In June of 1971 Zeldovich announced a spinning black hole must radiate ... “a spinning metal sphere emits electromagnetic radiation ... The radiation is so weak ... that nobody has ever observed it, nor predicted it before. However, it must occur. The metal sphere will radiate when electromagnetic vacuum fluctuations tickle it. Zeldovich's mechanism by which vacuum fluctuations cause a spinning body to radiate showed a wave flowing toward a spinning object, skimming around its surface for a while, and then flowing away. The wave might be electromagnetic and the spinning body a metal sphere ... or the wave might be gravitational and the body a black hole. The incoming wave is not a "real" wave ... but rather a vacuum fluctuation. ... the wave's outer parts are in the "radiation zone" while the inner parts are in the "near zone" ... the wave's outer parts move at the speed of light ... its inner parts move more slowly than the body's surface is spinning ... the rapidly spinning body will ... accelerate ...[the inner parts of the incoming wave] ... <and this> acceleration feeds some of the body's spin energy into the wave, amplifying it. The new, amplified portion of the wave is a "real wave" with positive total energy, while the original, unamplified portion remains a vacuum fluctuation with zero total energy. Zeldovich proved that a spinning metal sphere radiates in this way; his proof was based on the laws of quantum electrodynamics.”


Hawking undertook the task of applying quantum mechanics to black hole dynamics. While his formulation is beyond the scope of this page, a slightly quantitative and highly qualitative examination of the problem can yield a very good picture of what Hawking discovered. Hawking first attempted to examine the space-time outside the black hole using quantum field theory, which has a very different picture of empty space than the classical definition. His first step was to consider what happens when any field (for example, the electromagnetic field) is quantized in the space-time exterior to a black hole. The quantum mechanical description of a vacuum is space seething with virtual particles and antiparticles whose presence cannot be detected directly.

At first glance, this process of virtual particle creation may seem a little phony. With that in mind, we can consider the more tangible case of electric field particle creation. (This process can actually be observed by applying a strong electric field across a capacitor in a vacuum.)

The quantum mechanical description of the vacuum allows for the creation of the particle/antiparticle pairs, and the electric field tends to separate the charges. If the field is strong enough, the particles tunnel through the quantum barrier and materialize as real particles. The field necessary to accomplish this feat is achieved when the work done to separated the charges by a Compton wavelength equals the energy necessary to create the particles. It should be noted that conservation of energy is not violated, as the energy it took to create the particles would be precisely equal to the decrease in the energy of the weakened electric field. (NOTE: not necessarily just the BH mass loss).

Sources:
Carrol, Bradley W. and Ostlie, Dale A. An Introduction to Modern Astrophysics. Reading: Addison-Wesley, 1996.
Wald, Robert M. General Relativity. Chicago: University of Chicago, 1984.
Eisberg, R. and Resnick, R. Quantum Physics. New York: John Wiley & Sons, 1985.
Narlikar, J.V. Introduction to Cosmology. Cambridge: Cambridge University Press, 1993.
Hawking, S.W. Hawking on the Big Bang and Black Holes. New Jersey: World Scientific Publishing Co., 1993.
Hawking, S.W. A Brief History of Time. New York: Bantam Books, 1988.
Shapiro, S. and Teukolsky, S. Black Holes, White Dwarfs, and Neutron Stars - The Physics of Compact Objects. New York: John Wiley & Sons, 1983.
Thorne, Price, and Macdonald, eds. Black Holes: The Membrane Paradigm. New Haven: Yale University Press, 1986.
Wald, Robert M. General Relativity. Chicago: University of Chicago, 1984.

So, unless all of these boys are incorrect, it shouldn't be a surprise that any and all BH's have a magnetic field.

Some of the above quote are from other quotes and I have added the bold and underline emphasis. I have saved this to my own computer as a Word.doc so I would have to do a lot of searching to get to all the original material...Too lazy...

 

[Mike2]

When black holes rotate, don't they "drag" the reference frame with them, giving it a kind of rotation? Wouldn't virtual particles of the vacuum be dragged with the reference frame. And if the charges are separated by the horizon, then won't there be circulating charges and the magnetic field associated with it?

 

[Labguy]

When black holes rotate, don't they "drag" the reference frame with them, giving it a kind of rotation? Wouldn't virtual particles of the vacuum be dragged with the reference frame. And if the charges are separated by the horizon, then won't there be circulating charges and the magnetic field associated with it?

Not sure what you mean by "circulating charges", but frame dragging is an important contributor of the field generation, which is why the above big quote specifically mentions Kerr BH's (rotating). Virtual particles would have angular momentum, but when escaping the energy required is provided by angular momentum and the magnetic fields.

http://relativity.livingreviews.org/open?pubNo=lrr-2003-7&page=articlesu21.html
http://adsabs.harvard.edu/abs/2003astro.ph..5352I
http://www.sciencemag.org/cgi/content/abstract/295/5561/1874

 

[Mike2]

Not sure what you mean by "circulating charges",

I'm no expert by any means. I'm just trying to understand these things in terms of puemonics that are easy to intuitively understand. By frame dragging I assume there is a component of acceleration tangent to the horizon surface in the direction of rotation. And I also assume that accelerating in the tangential direction means there is a higher velocity of the virtual particles of the vacuum tangent to the horizon when compared to more distant vacuum away from the black hole. Then when the virtual charges are separated due to the horizon, the acceleration tangent to the horizon amounts to a circulation of these charges which causes a magnetic field that separates the charges even more. Does this sound correct?

 

[setAI]

speaking of rotating- from what i have gleaned on the subject it seems to me that Schwarzschild black holes could be unphysical- as they could only be formed by a non-rotating mass with a perfectly symmetrical collapse into a singularity- is this correct?

from this it seems to me since virtually all stars have some rotation and a collapse would amplify the rotation- that the only physical black hole would be more like Kerr rotating black holes with the inner cauchy horizon-inversion to 'normal' spacetime inside and no singularity but the missable neutronium ring at the center with possible Eintein-Rosen bridge inside the ring where the singularity would be-

is that right? as I understand it ANY rotation leads to the Kerr metric- not the Schwarzschild solution

 

[Labguy]

speaking of rotating- from what i have gleaned on the subject it seems to me that Schwarzschild black holes could be unphysical- as they could only be formed by a non-rotating mass with a perfectly symmetrical collapse into a singularity- is this correct?

from this it seems to me since virtually all stars have some rotation and a collapse would amplify the rotation- that the only physical black hole would be more like Kerr rotating black holes with the inner cauchy horizon-inversion to 'normal' spacetime inside and no singularity but the missable neutronium ring at the center with possible Eintein-Rosen bridge inside the ring where the singularity would be-

is that right? as I understand it ANY rotation leads to the Kerr metric- not the Schwarzschild solution

My very long quote in the 3rd post has in it:

However, many other research sites and past papers have noted that it is almost impossible to form a BH with no angular momentum (spin). Even the "no hair" statement by Wheeler was that a BH has only three observable properties; (1) mass, (2) angular momentum and (3) charge (usually net zero).

so no, there are not likely any non-rotating BH's.

The "Kerr BH" is thought to have the "ring singularity" of zero volume (I believe there is no zero volume and no infinite density) and I haven't yet heard of the "neutronium ring at the center with possible Eintein-Rosen bridge", even though some might speculate (ad infinitum).

And I also assume that accelerating in the tangential direction means there is a higher velocity of the virtual particles of the vacuum tangent to the horizon when compared to more distant vacuum away from the black hole.

Yes, but the difference in velocity would be due to both the BH's angular momentum and the effect of frame dragging. Those "other VP pairs" created away from the BH have no specific reference frame from which to judge velocity; they are just "there and then not there".

Then when the virtual charges are separated due to the horizon, the acceleration tangent to the horizon amounts to a circulation of these charges which causes a magnetic field that separates the charges even more. Does this sound correct?

A separation "due to the horizon" is a discussion of classic Hawking Radiation (HR) where one of the pair escapes and one doesn't. This leads to Wheeler's 3rd "no-hair" property of charge. But, I am talking about non-HR where two virtual particles are created and both can escape. As in the long quote I posted above, the energy for the creation of both pairs comes from the magnetic field(s) only. The energy that might allow both to escape comes from the BH's angular momentum.

 

[SpaceTiger]

So, unless all of these boys are incorrect, it shouldn't be a surprise that any and all BH's have a magnetic field.

Your references seem to be talking about magnetic fields associated with the Hawking process, which would have a completely negligible impact on the quasar light. The paper in the OP is claiming to observe magnetic fields of much greater strength in the inner regions of the accretion disk.

As for the MECO article, I wouldn't get too worked up about it. Their analysis rests on a lot of assumptions that are hard to verify. Quasars are extremely difficult to unravel because there are so many things going on in the vicinity of the SMBH. I suspect we won't see any definitive test of this model until we can directly image the accretion disk around a black hole (and even then, I'm not sure). It's worth noting that similar arguments have been made that support the existence of an event horizon (at least in stellar mass black holes):

http://lanl.arxiv.org/abs/astro-ph/0107387"

 

[Labguy]

Your references seem to be talking about magnetic fields associated with the Hawking process, which would have a completely negligible impact on the quasar light. The paper in the OP is claiming to observe magnetic fields of much greater strength in the inner regions of the accretion disk.

True, as far as the three new references listed, but we got on the subject of magnetic fields around a BH in response #4 and #6. Plus the OP quote from the article had said:

A well accepted property of black holes is that they cannot sustain a magnetic field of their own.

and I was just showing that all BH's would have magnetic fields; nothing about powering Quasars or Hawking radiation. That part is the reference that:

but Ramon Khanna and Yakov Zeldovich have shown that all black holes will have a magnetic field.

 

[yenchin]

There's another paper on MECO up on arxiv in case anyone misses it: http://arxiv.org/PS_cache/astro-ph/pdf/0608/0608178.pdf