Neutron Star to Black Hole

For our more obtuse friends:

ABSTRACT :
Abstract The angular momentum of the Kerr singularity should not be larger than a threshold value so that it is enclosed by an event horizon: The Kerr singularity with the angular momentum exceeding the threshold value is naked. This fact suggests that if the cosmic censorship exists in our universe, an over-spinning body without releasing its angular momentum cannot collapse to spacetime singularities. A simple kinematical estimate of two particles approaching each other supports this expectation and suggest the existence of a minimum size of an over-spinning body. But this does not imply that the geometry near the naked singularity cannot appear. By analyzing initial data, i.e., a snapshot of a spinning body, we see that an over-spinning body may produce a geometry close to the Kerr naked singularity around itself at least as a transient configuration.

The question, I believe is: "Whether a Kerr singularity rotates or not?" The point here is that a singularity is not like an ordinary object, such as, for example, a star. For an ordinary star, to say that it rotates makes perfect and well defined sense.
But, as I explained in some detail earlier, a singularity is not an `ordinary object', as we are used to commonly! Its an infinite density, infinite curvature boundary point for the spacetime, that is it is not part of the universe in an ordinary sense of the word. Since all physical properties blow up there, it is difficult to exactly attribute rotation to the same

So I would say the following: Despite the figurative language used above, which is done sometimes, the real scientific facts are I think what are outlined above. So, if someone says, "singularity rotates'', or the ''singularity created a black hole'' (e.g. in the case of Schwarzschild metric), I would not take a strong objection, but it is to be understood in the above detailed and proper sense.

 

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We are growing pad , hence we discuss

 

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http://www.astro.umd.edu/~miller/teaching/astr498/lecture13.pdf

 

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What was the point pad ?

 

That statement by our persistently obtuse friend, has been corrected a dozen times, yet still he persists.

Here's some more.....
http://www.physik.uni-regensburg.de.../gebhardt_files/skripten/Lect06Kerrmetric.pdf

http://www2.phys.canterbury.ac.nz/kerrfest/spin.html

And of course we have the paper by Roy Kerr himself...you know, the bloke that solved the equations dictating rotating BH's, and from what I remember, and true to your form, you have never once commented on!!!
I'm a bit lazy at the moment, but would you like me to retrieve that also?

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Paddoboy,

You are doing a wonderful job of copy paste various tit-bits from here and there on the net. Keep doing that !!

As soon as you start offering your opinion even on these small titbits, you expose yourself and commit a self goal. So please stick to your copy paste expertise only. Leave this singularity business to other experts on the forum, thats not your cup of tea (or may be mug of beer), at least as on date. May be you will grow up knowledge-wise one day, if you keep your sensory system open.

 

What professor Carlip had to say.....
" But the Kerr black hole certainly has nonzero
angular momentum, and this is present arbitrarily close
to the singularity, in the sense that (for instance)
frame-dragging takes place arbitrarily close to the singularity".
"There are ambiguities in defining local angular momentum
in general relativity, but in all of the approaches I
know of, the spacetime in a finite region arbitrarily
near to the singularity of the Kerr metric carries angular
momentum. An observer near the singularity will be
dragged along an angular direction because of this".

I really hate bringing all this up again Rajesh, but when you continue to be so obtuse and then follow that up with petulant arrogance, like "gotcha!"as if you are playing a game, or such childish banter as " Ideally I/Mods should blast you"!

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I have probably remarked a few times in our debates re you silly "head in the cloud arrogant" remarks...but still they persist, whenever you see an opportunity to misinterpret something else. That type of behavour really does nothing for you.

 

You see rajesh, what puts you behind the eight ball, [besides your "head in the clouds and arrogance"] is that you only ever comment on that which you can twist slightly to reflect your view.
I've commented on all the professors, all the posts by others, and even yourself.
I don't ignore that which is sometimes difficult to explain, while you ignore all references that invalidate your nonsensical invalidated claims.

 

Yes, plenty of them and all reputable, but you ignore all.

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You mean all the reputable links you are unable to twist or misinterpret?
All the ones that invalidate your nonsense, like the quote of yours from page 1.
Many more to go yet, but I'll hold fire.

Well since we are both amateurs, difference being I know my position while you do not, and since my position in most cases align with the more logical mainstream theories, while you in essence do not even accept the existence of BH's.
In the mean time as I have done with all your demands, they will be treated with the contempt they justly deserve, and my comments for what they are worth will continue. Hope that's OK with you?

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Paddoboy,

Just answer two questions from the options and get yourself a moral relief..

Q1. What is the RPM of spinning singularity ??

a. I do not know.
b. It exists, but no one knows except me and I cannot tell.
c. It is meaningless to assign any spin/RPM to singularity.
d. It must be spinning, as per me but not as per present mainstream theory.

Q2. What is the Planck's level parameter at which the singularity decides to rest ?

a. Planck's Length (Lp)
b. Plancks' Mass (Mp)
c. Planck's Time (Tp)
d. None of the above

Do not beat around the bush, no copy paste, pl answer these two questions from the options or you concede that you are trolling.

 

May be you, but I am not...You assume a lot.

 

Oh yeah, that's right...You are going to write up a scientific paper correct?
Let,s see what that paper will be about....BH's don't exist [ but no explanation for the effects we see] BH's have density, BH's do not have angular momentum...Anything I have left out?
Yes, you certainly are without doubt an amateur, and an anti mainstream one to boot.

 

No, you are the troll, as shown in this thread and the other BH thread with ignoring of all mainstream links...Perhaps you think they will disappear if you ignore them?

You answer a question...one you have avoided like everything else....
[1] How do you have observed frame dragging, when the BH is non rotating?
What causes the frame dragging?

 

Ok, I will answer...The profs (Dr. Abhay if I am right) very categorically stated that angular momentum is associated with ErgoSphere, that is like rotational energy also associated with the same spacetime around. Prof's assertion that energy/momentum is associated with spacetime makes sense because assigning anything to singularity is meaningless. And 100 times I have told you that this answered my question in the OP. Even Penrose process (you were ignorant about but by now you would have googled extensively) talks of extracting energy/angular momentum from Ergosphere not from singularity...But as I can figure out you cannot understand such complex issues and thats why you are insisting that ...Singularity must be spinning thats why frame dragging. Thats your incredulity, Paddoboy, due to shallow knowledge of the subject.

Don't worry, just follow my threads, participate in them, but don't cross me beyond a point, we all will learn in the process in depth, not some cosmetic terminology know-how. I am thinking of starting a thread on Neutron Star Degenerate matter, because I could see an ignorance in you and in ....... when you guys referred to Nuclear Force on the point !! Thats plain shallow understanding.

But for time being, pl answer those two simple questions, out of options given...without beating around the Bush..or concede that you are a troll...or at least concede that you are learning and due to ego not able to reconcile the fact that you could be wrong after 8000+ posts.

 

You seem be asserting that, everything inside the event horizon is the singularity. That is a naive understanding, but one I think was mentioned by Prof. Moore, when he was clarifying what he means, when he uses the word singularity. I believe he called that conceptualization a coordinate singularity that changes depending on frame of reference. You seem to be caught up in the situation Moore described as a coordinate singularity, which I would describe as an illusion of misunderstanding.

However, I think the problem is with definitions of terms. It is unfortunately common in the literature to refer to the way that Kerr and Schwarzschild metrics behave badly at an event horizon as being a "singularity." But this is just a singularity in the coordinate system. (Prof. Moore - extended quote below)​

TO BE CONTINUED

 

CONTINUED

In another earlier comment,

Presumably, however, the Kerr metric's values of a (angular momentum per unit mass) and M (mass-energy) will be conserved as the original source falls into the singularity. But the point is that in GR the singularity is simply a singular mathematical point in the vacuum solution that now applies everywhere *else.* We can no longer talk meaningfully about the singularity's spin or even its mass. We can only talk about (or measure) what we observe imprinted in the gravitational field. ... (Prof. Moore - full comment quoted below)​

...The physics of the field outside the Kerr black hole's event horizon (which is the only thing that we can possibly observe from an outside perspective) is completely disconnected from the singularity. (Prof. Moore continued - full comment quoted below)​

I separated the two parts of Prof. Moore's comment for emphasis. The first section clearly describes the singularity as a point and that there can be no meaningful description of mass or angular momentum associated with a point. However, what you seem to be focusing on is the last part, that makes a different and completely separate distinction/separation, specifically between what we can observe and what we cannot. You seem to confuse what can be observed with what can be theoretically described. Go back and re-read that first sentence in the quote above,

Presumably, however, the Kerr metric's values of a (angular momentum per unit mass) and M (mass-energy) will be conserved as the original source falls into the singularity. (Prof. Moore)​

Even where talking about mass and angular momentum of a point can not be meaningful, we must presume that they are both conserved, as the black hole is formed. The geometry does not describe any mass and yet it and any angular momentum associated with it must be conserved. The theoretical solution does not fully describe reality.., what must be real. It does not describe the mass inside an event horizon, but since the mass and angular momentum must be conserved, there must be mass inside the event horizon....

Spacetime as described by both the Swartzschild and Kerr solutions describes spacetime even inside the event horizon and all of the way to the singularity.., a mathematical abstraction that represents the point or location where the math breaks down. Meaning that theory is no longer able to describe the singularity as having any mass, size/dimensions or angular momentum, even where they must be conserved.

In the Swartszchild case it is a point. You cannot ascribe any physical characteristics to a point, including angular momentum. In the Kerr case it is a ring singularity, which is even more difficult to describe in words, to a lay reader. In both cases you are stuck outside the event horizon.., and seem to be assuming that everything inside the event horizon is the singularity. That is not consistent with GR or either theoretical solution to EFE.

 

Again, as is obvious with the majority of your posts, you twist, turn and squirm. This is the methodology of the "great Farsight"

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Again, how can you have "frame dragging" without any other rotation?
Let's add another question....
What is being "frame dragged"?
Spacetime did I hear you say?
Next question:
Where does this space time end? I mean is spacetime continuous, or do you see it in separate sheets so to speak?

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Do you view the EH as a physical barrier?
Again let me make it quite clear, despite your demands and commands for me not to.
BHs do spin: We call them Kerr BHs: That spin is evident in the ergosphere, and logically deduced in the spacetime that makes up the majority of the BH, right up to the Singularity.
From here, although any information about the Singularity is nil, I see it as a logical inference to view the Singularity as also rotating, as agreed to in my many references which you totally ignore, and as allowed for even with the finality of the stringent reply from our latest professor thus.......
" So, if someone says, "singularity rotates'', or the ''singularity created a black hole'' (e.g. in the case of Schwarzschild metric), I would not take a strong objection, but it is to be understood in the above detailed and proper sense".


Now onto your other red herrings designed to distract from your silly original statement thus........

Let's repeat that just to make it quite clear....

That misconception of yours amongst many others which you have never recognised, shows all just how dishonestly stubborn and just plain wrong that you are.

Also [another red herring] please start your thread on Neutron stars and nuclear forces...It will be nice to again see you try and bamboozle others here with your ignorance of mainstream physics and cosmology.

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Now admittedly, I am only an amateur just as you are: We have no qualifications, neither of us, and as such must weigh through slightly different interpretations of Kerr BH's from different people and reputable links.
That's simply logical. Where You differ from me in your amateurish status, is that you obviously suffer from delusions of grandeur, and chose to ignore the many expert links, and only "cherry pick" isolated quotes that you are able to misinterpret.
Those are undeniable facts.

Again, let me make it quite clear, [at the risk of provoking your ire, Kerr BH's by definition spin or rotate: Both within the ergosphere [frame dragging] and within the BH EH itself, [the spacetime/BH causing the frame dragging

 

Yes! And that is basically what all our professors have said, in so many different words and ways.
To continually refuse to recognise that, indicates an agenda of sorts.
Havn't quite worked it out that agenda as yet, whether just plain delusions of grandeur, or some Creationist/God Bothering agenda.

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Again, coupled with your agitated state, you seem highly confused.
OnlyMe will correct me if I'm wrong, but I presume when he raised that point, he was referring to the stages in a star's collapse where gravity eventually overcomes the strong nuclear force.

 

The theory predicts the angular momentum of the collapsing mass is conserved. So it has to be spinning wherever it is. The theory predicts the singularity is a spinning ring. Regardless what you think and misunderstand. You clearly can't understand what professor Carlip meant by the spacetime being dragged from the singularity out. It's called physics and your comments on the physics is comments from someone who couldn't do this analysis if your life depended on it. Same goes for Farsight and the rest of the ignorant cranks buggering up these threads with irrelevant nonsense. Trolling=buggering up.