Neutron Star to Black Hole

Why don't you respond to the many crazy erroneous ideas you have about BHs
that are fact, and evidenced in two threads.
Your crazy erroneous ideas.
[1] BHs do not exist or are unlikely:
[2] BH's have meaningful measurable densities:
[3] The Schwarzchild limit and compulsory collapse does not hold:
[4]The Singularity not being in vogue at the Planck/quantum/Singularity level:
[5] Frame Dragging in the Ergosphere is not caused by any rotating mass:
[6] A Kerr metric BH does not spin:
Are you backing away from any of that?

Why dont you respond to the fact that I have revealed your religious agenda?

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Again, just so you have the message...No one [other than you] has ever said a kerr singularity does not have angular momentum.

It is you railing against everone else...not the reverse!


PS: Please accept the fact that I do not respond to your arrogant demands, typical of all you God Botherers.

 

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Obviously I am having trouble being clear, otherwise you are intentionally quoting me out of context and reading your own agenda into my words, so....

If the discussion is restricted, to discussion of theoretical solutions to GR, spacetime can be described, or as Bruce put it predicted, all the way to a location, as one of the professors put it, arbitrarily close to the singularity. The singularity being the location in spacetime where the mathematics of the solution, that is the description of the gravitational field breaks down and no longer makes any sense... What that means is that in the case of the Kerr solution or any similar solution that includes rotation, all of the spacetime, both inside and outside the event horizon rotates and thus has some angular momentum, which originates with the frame-dragging effect of the orginal collapsing mass.

It is also not unreasonable to assume that the original mass and any angular momentum it had is conserved even as it collapses into the singularity, even when we cannot mathematically describe it any longer, once we arrive at a singularity.

When we attempt to place the solutions into any real context we run into problems at the event horizon, because we cannot observe anything beyond that location in any solution... That does not mean that we cannot predict the nature or character of the field all the way to the singularity. It only means we cannot confirm those predictions by observation or experience.

I am pretty sure all of the professors who have responded, know that these solutions are theoretical and that the singularity is a mathematical abstraction that has no counterpart in reality. This is where I believe you, are stuck and have no real clue...! When I or any of the professors, either indirectly or directly.., reference some future model of quantum gravitation, as the next step in a description of reality.., it is a statement that should be read as, any explanation of the character and composition of the collapsing mass and angular momentum of that mass, after it passes the location we refer to as an event horizon, is the subject of quantum mechanics and quantum gravity... In that world.., it is not likely there will be any singularity.., and even some of our fundamental assumptions about gravitation may once again.., be reconsidered and even evolve.

Rajesh, your comments seem to be placing a test of reality, on the theoretical conclusions of mathematical solutions to the EFE. This is a confused and naive evaluation/approach.., or perhaps an argument based on intentional misinterpretation.

 

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And Robert Wald.

 

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Bruce, I have a question about the portion in bold above. I have always seen GR as a description of a gravitational field in a more pratical sense. Like the fields associated with observable objects, planets, stars, etc... And the singularity as a conclusion emerging from extensions of GR, predicted by a variety of solutions to the EFE. This may be a technical distinction, but it separates the real world observable success of GR, from the theoretical extensions associated with black holes.

 

I really cannot see it being anything else. Sad.

 

The mass of black holes are not a 'theoretical extension'. No more a theoretical extension than the mass of the earth. Clearly the mass of the black hole is located at the center of the black hole. Because the theoretical model can't describe that geometry we're stuck with calling it a singularity and for practical purpose the place where all geodesics terminate for the Schwarzschild geometry but not for the Kerr geometry. GR is a local theory of gravity, spacetime curvature. The mass of the black hole contributes to the local spacetime curvature, in a dynamical way, through the propagation of gravitational radiation. That's how it's predicted to work. I know what you think about this science with your "practical sense" and "theoretical extensions". Whatever. Irrelevant to the science.

 

Do you really know about EFE ?? The number of times you have used the word EFE in last two threads tells me that you are throwing this term just to sound knowledgeable.

You do not know of course, that medicine and astrophysics are two streams of science which very heavily rely on observational data, that is reality. I ignored you when in the last thread regarding BH, you made some comments about reality and theory, but now it is clear that you are fully confused about the entire maths/physics around Black Holes or anything which is possibly 8 light minutes away from us.

Please get this notion out of your head, that theories around BH etc are only mathematical artifacts, these are theories which explain the observational data. By making such statements again and again that this is theory and not reality...you are fooling yourself only. In this thread you are just making a Simple Harmonic Motion, this way-that way-this way...decide your stand what you want to say. All those who can read English understand what you want to say..

 

Funny, you've said similar about myself also.
I'm not sure about anyone trying to sound knowledgable more than yourself, and failing miserably.
Let me reiterate.
You have said so far that
[1] BHs do not exist or are unlikely:
[2] BH's have meaningful measurable densities:
[3] The Schwarzchild limit and compulsory collapse does not hold:
[4]The Singularity not being in vogue at the Planck/quantum/Singularity level:
[5] Frame Dragging in the Ergosphere is not caused by any rotating mass:
[6] A Kerr metric BH does not spin:

Science certainly rely on observational evidence and experimental evidence, and the principals of physics that have been established and handed down by the giants of the past, [you know, the ones you chose to ignore, so you are able to spout your own fairy tales] and the Logic and reasonable assumptions based on that knowledge.
The rest is just further examples of you trolling.

BH's are a theoretical concept, but a theoretical concept based on much evidence plus the fact no one can explain the observations of the effects on spacetime, matter/energy that we observe, other than by BH's
Theories also grow in stature and certainty the longer they keep matching those observations.

In accepting the reality of BH's, reasonable cosmologists such as Roy Kerr has showed that most of these would have angular momentum.
Evidence has been observed indicating "frame dragging" in what we call the ergosphere, and as such aligning with current knowledge that "frame dragging" is caused by rotating mass, added to the other facts re the conservation of angular momentum when the star collapses, it's quite reasonable, as indicated by at least two experts, to expect logically, that the BH/spacetime is rotating up to the vicinity of the Singularity/mass, and that this same Singularity/mass would also be most logically rotating/spinning.

The more you spout your nonsense Rajesh, the further out on a limb you situate yourself.

 

Question #1:

Explain to me Rajesh, when has anyone observed an event horizon or a singularity?
Both have been predicted not by Einstein's field equations, but by solutions to those field equations.., and there are more than one set of solutions. Some similar and some not so much.​

On top of that, unless you define a black hole as everything within the event horizon including the event horizon, even those solutions don't describe a black hole. They describe the spacetime associated with what remains of the orginal mass, but cannot be observed...., wait for it..., because it is inside of the event horizon.​

That leads to question #2 through 7:

What is your exact definition of a black hole?
Is it just the singularity?
Is it everything inside the event horizon?
Does it have mass?
Does it or can it have angular momentum?
Does it or can it have an intrinsic magnetic field?​

After answering those questions, why not explain just what you really meant in the post quoted above.

Yes I have taken the short cut of referring to Einstein's field equation as EFE instead of writing out... beyond that did you have a point?

OPPS! After reading paddoboy's post I guess you may have already answered some of my questions. I guess I am guilty, of not paying attention!

BTW EFE is not a word it is an achronym for, Einstein's field equations.

 

Nice post brucep, pretty close to the way I see things, and I don't believe OnlyMe is too far away, nor any of the professors in actual fact.
There is only one dramatically opposing discord to BH cosmology being discussed here, and he has been shown to be totally wrong in all respects, [see my list] and in this regards, and I'm 99% sure he is another religiously based fanatical God Botherer.
No one could be as obtuse to the logic and reason that the professors, yourself OnlyMe, and myself have put for him to consider.
It is down and out God Bothering trolling!

 

Another reply!

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This was another good response Tashja. I am unsure how some here will read the professor's comment as a whole. His concluding statement gets to what I was earlier trying to draw out in my question to Bruce. My wording there was it seems unfortunate.

 

How do you read it OnlyMe?
Again in my opinion, all replies are putting a particular emphasis on one view or the other.
While saying the short answer is no, it is impossible to assign spin to the Singularity, it still is not saying with firm affirmation that the singularity does not spin.
Do you agree?
Reading it as a whole, he's saying the choice of "answer" as such is "undecided"

 

Its getting weird, now the argument from you guys has become absolutely irrelevant as you have started talking about reality or non reality of Black Holes......we are talking about no less than thousands of light years ago and still you guys want a discussion on reality as if Black Hole is Next Door neighbor.

We must stick to theory and theory of Kerr BH is as follows...

1. Angular Momentum and Rotational Energy is associated with ErgoSphere.
2. ErgoSphere is outer geometry of BH beyond r+ (The outer Horizon).
3. There is no frame dragging associated inside Event Horizon as nothing can be observed inside.
4. It is meaningless to say that singularity is spinning.
5. Inside r+ the time itself becomes spatial so even between r+ and r- frame dragging cannot be associated.
6. Via Penrose Process the rotational energy can be extracted which may reduce the spin of BH, albeit it will take long long time. Reverse Penrose Process is also possible.

My whole object since more than last 100 posts, was with Paddoboy's assertion that everything of Kerr BH is spinning, there is frame dragging inside Event Horizon and even singularity is also spinning......I still insist that theoretically this is BS.....and this is also BS that in case of non rotating Black hole singularity lies at Planck's level.........Paddoboy keeps on camouflaging the main issue.


This is the theory....if any one has any problem with this, then he can educate himself or wait till he gets educated.

 

Nobody, says it does or that it doesn't. The math and theory stop describing anything when you reach singularity.

I am pretty confident that most of these professors, do not believe that singularities exist in reality. That black holes do have a physical mass inside the event horizon and that we just don't have any theory or science that can describe that mass.., and still recover the success that GR has had in describing and predicting the field of objects we can observe.., planets and stars...

Personally (and this is speculation), I believe that the next step and advance in understanding and describing gravitation from a fundamental perspective (general relativity is a General perspective and very successful, in a macroscopic context), will be found in a reexamination of the relationship between inertia and gravitation, as emergent quantum phenomena. Which though I don't believe it will have any significant impact on general relativity as a field theory, it may have a significant impact on how it is understood conceptually.

Sorry for the diversion, the professor's last comment seems very clear, in stating that the math in the case of singularities is just math and does not describe anything real... But that does not detract from its ability to accurately describe a gravitational field, anywhere other than at the singularity.

 

Some of what you say is true and some is nothing more than hogwash!

You complain about a separation in time in thousands of light years and then speak about the ergosphere as if it did not save a similar separation in time. The only difference between the spacetime associated with the ergosphere and spacetime inside the event horizon, is that anything inside the event horizon cannot be directly observed. Both are similarly separated in time from our present.

#3 you have provided nothing to prove your position. The Kerr solution says it does have angular momentum and to be consistent with experience that can be observed and measured that angular momentum must be associated with the frame-dragging effect, even when we cannot observe or measure it.

#4 saying anything about a singularity other than it is the location where the math/theory breaks down.., is meaningless. That means even the way you phrase #4 is meaningless because it implies, it's opposite.

#5 is more speculation about how a theory that begins to behave badly at the event horizon affects something in a region of spacetime where we cannot test the statement...........

Re-read that last comment of Professor Wiltshire's.., and then tell me how a mathematical science fiction, has any impact on what happens in reality. Again even though we cannot observe or describe it, to be consistent with what we do know and can prove about mass and gravitational fields, in the place of the singularity there must be mass, which almost certainly has some angular momentum and is the source of the black hole's gravitational field... And yes we still have troublesome issues to resolve, involving the exact nature of spacetime at the event horizon, but that is a burden that science must deal with.

 

Ignoring your irrelevant bullshit, let's get down to your "claims"

Yes. But remember this angular momentum of the ergosphere [spacetime] by definition, is caused by a rotational mass.

Yes. Ergosphere is contained by the "static limit" and the EH proper.

Obviously nothing can be observed within the EH, but just as obviously, the Kerr metric by definition is rotating, plus of course as already stated, frame dragging is caused by a rotational mass.

It is just as meaningless to claim it is not spinning.
Logic and common sense though, tells us that to assign spin to the singularity is reasonable.

Logic and sensibility says otherwise.

This has nothing to do with the question at hand.

That's your perogative to think what you like. But I do have a couple of questions about that view in my next post.

Obviously it is you who needs educating, or are you now claiming some sort of conspiracy with regards to all members here and those of the experts that have refuted your stance ?
Again, I have a couple of queries for you in my next post.

 

To Rajesh:
I have made an accusation against you, namely that you have an agenda, that being that you are basically a God Botherer of sorts.
I have reasons for claiming this which I will now list.
[1] You have started a number of threads, all questioning mainstream cosmology, [not that there is anything wrong with that] and mostly perceived dissatisfaction with the answers you have been given.
[2] You have started two recent threads re BH's by asking questions in the OP's and expressing a complete ignorance of BHs and a layman understanding of them.
[3] Both these threads have progressed then to you making "expert" professional claims, including some mathematical derivations, while still refuting/deriding the accepted mainstream knowledge.
[4]These methodologies have been used by other anti mainstreamers in the past, particularly the God Bothering kind, so a precedence has been set.
[5] Finally you have ignored my original accusations re the God Botherer in disguise that I think you are, by nether objecting or confirming.

If I am shown to be wrong I will withdraw those accusations and apologise.
The ball is in your court.

 

Not trying to outdo tashja and the excellent job he has done, but I thought I'd contact an old cosmologist I once crossed swords with on a now defunct forum.
Here was his reply.



The singularity in general relativity is not a "thing" so ascribing properties to it is not really a good thing to do - but when we have a better description of gravity, telling us what it is the singular nature of the GR equations are hiding, it will have an angular momentum associated with it.

Cheers - G

Prof Geraint F. Lewis,
Professor of Physics & ARC Future Fellow,
Sydney Institute for Astronomy,
Associate Head (Research),
School of Physics,
The University of Sydney,
NSW 2006, Australia

 

Nice reply, Paddo!

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