Neutron Star to Black Hole

Discussion in 'Astronomy, Exobiology, & Cosmology' started by RajeshTrivedi, Jan 12, 2015.

  1. paddoboy Valued Senior Member

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    Therein lies the crux of the whole situation, and what Rajesh appears to be blinkered from.
    Why would angular momentum originate at the ergosphere?
    It is called frame dragging [Lense Thirring effect] which specifically and by definition is caused by a rotating mass.
    So where is this mysterious rotating mass?
    Then we predict the ring singularity. Do we have a ring singularity if it wasn't spinning?
    Again it is totally reasonable for someone without an agenda, to assign angular momentum to a Kerr metric BH [all of it] as well as a rotating mass in whatever condition it exists.
    Again, despite being written off by Rajesh as inconsequential, when these professors are asked about the ring singularity, if by a stretch of the Imagination it was not/did not spin, then obviously that is what they would say.
    To deny that is to deny fact due to a burdensome agenda, which includes from day 1, his belief that BH's do not exist, and appears to be trying to create some sort of manufactured paradox to support that ideology.
     
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  3. paddoboy Valued Senior Member

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    Yes tashja has done a fantastic job, but to no avail.
    You still do not get it.
    Some professors openly say that it is reasonable to assign angular momentum to the singularity/BH proper.
    Others say that we "are unable" to assign, or "it is meaningless" to talk about, meaning it is beyond jurisdiction of our current models.....
    None say the Singularity does not spin!!!!!!
    Which if that was the case, they would certainly do.
    Please give them some credit.
     
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  5. RajeshTrivedi Valued Senior Member

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    Physics is not your forte !! Now even the maths !!

    And why not learn by yourself by just referring to those two links...they will clearly tell you how singularities originate in equations.
     
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  7. paddoboy Valued Senior Member

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    Both links agree with what everyone has been saying, bar one....YOU!
     
  8. RajeshTrivedi Valued Senior Member

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    So, you also agree with 'OnlyMe' that singularity has nothing to do with division by zero....??
     
  9. tashja Registered Senior Member

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    Prof. Kaku explains it in this video. Skip to 18:24

     
  10. RajeshTrivedi Valued Senior Member

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    Thanks, Tashja .....I can be accused of arguing with ignorants for quite some time..
     
  11. OnlyMe Valued Senior Member

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    Tashja, Kaku's explanation is the flip side of Prof. Thorne's earlier comment about explaining physics in English!

    There is a lot of confusion around the whole idea of dividing by zero. See the following from another thread:

    James was wrong in the portion in bold above. For his statement to be true 0 would have to be equally to infinity, which he earlier, in the underlined portion, said was not true. The result of division of anything by zero, is undetermined or when using English could even be described as James did (below) in a later post in the same thread. By the way, if you start with 8 ducks and wind up with more that 8 groups of ducks, the original 8 ducks must have been getting busy, during an unspecified period of time!

    EDIT CORRECTION: James said groups of zero ducks... But still I think it misrepresents division by zero.

    Kaku was wrong when he used the example 1/0= infinity. A mathematical division by zero is not the problem. The infinities comes from associating any mass with a point which has no volume. Einstein's field equations or rather solutions to those equations where you have a mass whose density is described by the volume of a point, which itself can only be described as
    0 x 0 x 0 = 0.
    But that is an erroneous description of the volume of a point, because it treats 0 as length.

    As I have said the trouble in this discussion is that it is in English. One should pay more attention to the fact that almost all credible references describe the mathematics as breaking down at the singularity, than any attempts to describe that math in English.
     
    Last edited: Feb 11, 2015
  12. OnlyMe Valued Senior Member

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    Rajesh, at this point I would say you are either yourself ignorant (note I did not say stupid), or you are trolling.
     
  13. paddoboy Valued Senior Member

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    Stop being so dishonest. I'm saying again, that a Kerr metric BH has angular momentum, and that the ergosphere that we have some evidence for, is a direct result of that.
    I'm also saying that you have openly admitted to believing BH's do not exist.
    From the opening debate about BH's, you have expressed many contrary invalid scenarios which you now constantly ignore and which I can just as easily constantly keep listing.
     
  14. paddoboy Valued Senior Member

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    21,225

    And of course I'm also saying that the classical point Singularity most likely does not exist. GR breaks down at the quantum/Planck level and the best scenario is that a surface of sorts exist at this level.
    They are reasonable assumptions along with the reasonable assumptions that the Kerr ring singularity/mass does have angular momentum, thus causing the frame dragging at the ergosphere that we have some evidence for.
     
  15. paddoboy Valued Senior Member

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    21,225
    I'll add something else that may help alleviate the confusion of our anti BH friend....
    The only possible physical part of any BH is of course the mass, that has collapsed to at least the Planck/quantum level and as a result beyond the parameters of our current models.
    The rest of the BH is only mathematical parameters, at which certain theoretical concepts are reached...eg: the EH proper, marks the boundary at which light cannot escape.
    But irrespective of those mathematical parameters, the properties of the spacetime, EH and beyond, are governed by the properties of that singularity/mass. eg: The angular momentum of the collapsed star is conserved in the mass that makes up the BH, and is responsible for the Kerr metric as defined, and also the ergosphere, or frame dragging, which again by definition is caused by a rotating mass.

    Now while we may have no observation of what is on the other side of an EH, logical sensible predictions based on a few scientific principles, enable cosmologists to reasonably assign properties to that BH/singularity/mass such as angular momentum.


    Last from me today fellas, as I have my 55th Old Boys reunion on in a couple of hours. 13 of us left that regularly attend, plus one of our teachers, who gave us all at one time or another, six of the best for inappropriate behaviour.

    Please Register or Log in to view the hidden image!

     
  16. RajeshTrivedi Valued Senior Member

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    OnlyMe

    You should not make such loose and irresponsible statement about Prof Kaku....Rather you should learn first how singularity manifests in equations. If you cannot learn by yourself, then you can seek help on this forum.
     
  17. OnlyMe Valued Senior Member

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    Rajesh, you have been making statements like this for how long now?... I asked that you demonstrate just how division by zero leads to the infinite mass densities and gravity in the field equations and from you nothing, but comments like above.

    Kaku was attempting to explain in English what is happening with the math which does not translate well. His example suggesting that division by zero, is not accurate other than in an intuitive or conceptual manner. What is certain about his explanation and the comments of many of the Professors that Tashja has obtained email from, is that at that same point in the equations..., they no longer make any sense.., the mathematics breaks down... Even if we were to assume that division by zero did equal infiniteis, the fact that in the same breath those who know, equate the same results with the breakdown of the math, invalidates the earlier interpretation/conclusion. Both cannot be true and everyone agrees that the singularity represents a breakdown in the math of the solutions.
     
  18. RajeshTrivedi Valued Senior Member

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    You obviously did not read those two links which I provided you to understand how singularity appears......You could have taken my help and I would have gladly shown you what happens when Delta -->0 and Rho --> 0 in those equations....But you have to first reach to that step. You have to start with limiting functions when denominator ---> 0. Then you won't ask/raise such silly questions.

    Yes as on date for you this is all English....pure English...no maths, no Physics...........Please learn something before acting as a preacher..I am sorry you are just an imposter.
     
  19. OnlyMe Valued Senior Member

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    You have again failed to explain yourself! Provide a reference to support something you have presented and it may mean something, just posting see this and a link is not a discussion.., especially when you link a Wiki page and 26 pages of math with no specific reference.

    As I have been saying all along, dividing by zero does not mean what you think it means or what Kaku said in a literal sense. 1/0 does not equal infinity and neither does x/0! Any equation that leads to either of the above only signifies that the math stops making sense. And thus in a strict mathematical context one can say nothing meaningful about singularities other than they cannot be described as having any physical characteristics and do not exist in reality. See the following for a rudimentary explanation...
    Even then many of the professors we have seen responses from, admit that reality will be somewhat different than the predicted singularities and that black holes do have mass, even mass with an angular momentum.., and that conceptually is not unreasonable to think of a Kerr ring singularity as having angular momentum... Mathematically it may be undefined, but conceptually to be consistent with everything else we know of the universe, mathematical singularities point or ring, are mathematical science fictions. We just don't know what the reality is as of yet.
     
  20. RajeshTrivedi Valued Senior Member

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    I gave you the page number also, but I understood your inability to understand that kind of math..

    Nonsense. For starter...find out the density of a 3 solar mass non spinning BH as it approaches - repeat approaches..to singularity.....You can find out the density first at r = 10^-35 meter and then slowly try to imagine r--->0, kind of two step solution and this way you will learn to equate infinity with large numbers, not with some 0/0 type uncertainties.

    Despite this you say or agree that...singularity must be spinning.....how convenient !!

    Pure gibberish !!


    I have been telling this for quite some time that you have no idea beyond small knowledge of acronyms and some technical words.........You call Prof Kaku wrong, and now you without knowing that Kerr Metric is the exact solution of EFE, call it a mathematical science fiction...please keep your opinion to yourself....and speak for yourself, do not use this ...we....we...again and again, if you are including anybody other than Paddoboy. First understand what is the meaning of singularity, How it originates in the equations, then attempt to respond...till then please keep lurking only.
     
  21. river Valued Senior Member

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    9,182
    Singularity

    Is the end of the life of mass rotation

    It will die out , because thats gravities consequence

    Hence singularities are a mathematical image , not a physical image
     
  22. OnlyMe Valued Senior Member

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    Rajesh, you have not demonstrated that you understand any of the math you point to! That is what I have asked you to show, how you arrive at the conclusion that x/0 = infinity!

    I did miss your page number reference. Partly because you failed to say who your link was referring to and when I open a link the first thing I do is try to determine its authority or author. All I got was what appears like a class handout for an unidentified class, that was 26 pages! Nowhere in that reference is the author identified.... And again you have never explained the math you seem to be pointing at, so spending any significant time on external reference trying to reconstruct what you have not clearly established..., is not something I am interested in. Make your own case and if it is about the math include the math and then provide a reference.

    You seem above to be confusing theory with reality. You do understand that both the Schwartszchild and Kerr Solutions assume that there is no other mass in the universe. I don't think anyone believes that the Schwarszchild case exists in reality and while the Kerr solution does a good job of describing the gravitational field of real observable objects.., planets and stars.., as it approaches the singularity.., the solution and math breakdown.., meaning they no longer represent anything expected to exist in reality.

    More directly are you back tracking or sidestepping your earlier comments? Above you avoid any direct reference to 1/0 or x/0 and retreat to statements where r (only) ---> 0, the place where most credible theorists admit that the solutions and the math breakdown... In plain language the point where they no longer make any sense! The point referred to as a singularity.

    Yes Rajesh, I do make and understand that there is a difference between a mathematical singularity, that cannot exist, and reality.., even when we cannot describe what is real where we cannot directly observed it.

    You seem very confused to me! Even the professors Tashja has provided email comment from seem to distinguish between theoretical conclusions and what can be expected to be real. Usually deferring a description of what is real until we have a successful model of quantum gravity to explain the detail.

    Tell me Rajesh: Do you think anyone other than yourself believes (because I have no idea what you believe), the singularities associated with any solution to Einstein's field equations are real objects?

    I accept that you are having difficulty understanding any of this... But in order for a comment like yours above to have any meaningful validity, you must first present some credible explanation or description of just what you believe, is the case! So far you are just waving your hands around and not even in any consistent direction.


    You are once again asking for something you have not done yourself! All you are doing is making unsupported derogatory comments about what others post....
     
    Last edited: Feb 12, 2015
  23. OnlyMe Valued Senior Member

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    I guess you accepted the following from my earlier post, because you did not have anything to say about it. Here's a second chance.

    On a separate note,

    Remember this from Prof. Wiltshire's response to Tashja's question,
    Therefore the inner horizon and anything "inside" the inner horizon - including the ring singularity- is unlikely to exist in the physical universe anyway. It is just a formal property of the exact mathematical solution. I know Roy agrees with me that the interior geometry of the Kerr solution is just mathematical science fiction, as we have discussed it many times.


    I assume the Roy he refers to is Roy Kerr. His full comment is included below.


     
    Last edited: Feb 12, 2015

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