Neutron Star

Discussion in 'Astronomy, Exobiology, & Cosmology' started by RajeshTrivedi, Apr 7, 2015.

  1. Q-reeus Valued Senior Member

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    2,606
    As commented last time, I have no real idea what the distinction can mean. Please explain clearly a scenario whereby there is 'core collapse' directly to a SMBH. It seems to imply a preexisting super massive star. There is a general consensus the upper limit to a 'modern' star is ~ 250 M solar. Above that limit stellar formation is unstable and there is break up to multiple star formation, and/or violent mass ejection. That's way smaller than any believed galactic center SMBH that range afaik from ~ 10^6 to ~ 2*10^10 M solar (so far observed).
    We have gone over this in a past thread. Yes 'average density' is much below that of a hypothetical (and immediately unstable for reasons already laid out) NS of such mass. Actually, for a ~ 10^9 M solar SMBH hypothetically formed by radial infall of a uniform distribution of typical stellar mass stars, the EH forms while at least most such stars are still individual stars i.e. tidal forces are too weak to disrupt them at the time of fall past EH. Basically a 'dust' accretion scenario. Once in, the standard story is a one-way journey with no stopping en route. Unless you believe in Black Star physics or such.

    Now, I have answered all your relevant questions and then some. Instead of playing games here and I now call on you to finally answer all my unanswered and relevant questions from previous posts:

    A: From #48: Sort of looks very much like a standard BH scenario has insisted on taking over, wouldn't you say?

    B: From #55: I will take a stab and assume you are referring to the 'gossimer thin shell' of #29 as a collection of many point particles. So? Do you concede the argument and conclusion is sound? Do you further concede things only get more extreme in terms of curvature, hypothetical shell stresses etc. as one descends below EH? Assuming so, what's left to argue over?
     
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  3. RajeshTrivedi Valued Senior Member

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    1,477
    You have answered your objections only, firstly you are suggesting that an SMBH can only form with mass accretion as beyond 250 Solar Mass the star may not be stable as single entity......So as per you all these SMBH are kind of mass accretion only over and above a small BH.

    Now if we take a 250 Solar Mass star core, even here also the EH shall be much larger than the required NDP collapse size... So you are conceding that that NS formation (NS = after EDP over come and all neutron in core where NDP is tussling with Gravity) is inside EH.......if so then your objection is only of stability of such BNS inside EH, not the existence per say. Have I understood you incorrectly ??
     
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  5. RajeshTrivedi Valued Senior Member

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    1,477
    Paddoboy,

    Density = Mass / Volume
    Planck's Length = 10^-35 meters
    Volume at Planck's level =10^-105 (indicative)
    Solar Mass = 10^30 Kgs

    Density = 10^135 Kg/M^3.........

    Total Mass of Universe = 10^55 Kgs

    So, it is like you have compressed 10^80 universes in 1 cubic meter......(less than a coffin volume)

    How this makes a heap more sense than infinite density ?? (in the context of Density)
    Yes, as a number any number makes heap more sense than infinity...
     
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  7. Q-reeus Valued Senior Member

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    2,606
    It's believed most if not all SMBH's formed billions of years ago when matter densities were generally significantly greater than now. The details of formation under such conditions might or might not require gradual accretion onto a single 'seed' BH.
    No. The standard scenario there has core collapse initiated owing to pressure at center exceeding what NDP can counter. A 'seed' BH is believed to thus initially form there and grows outwards. As it's formation undermines stability of immediately outer layer, progressive BH growth from core outward goes hand-in-glove with progressive collapse of NS matter outside of BH. Eventually the entire NS is consumed from inside out. One can ask serious questions about e.g. time frames of such scenario from different perspectives - but don't ask me to elaborate on that last statement!
    See above. And btw you have not answered my questions from last post, which in turn point back to earlier posts, and bear heavily on your last query. Please do so now.
     
  8. paddoboy Valued Senior Member

    Messages:
    21,647
    I do not give much credence to your figures, nor in most of your claims while they remain unreferenced and without a link...sorry.
    And yes, as a number, as per definition, and as a fact, any density at any level makes far more sense then Infinite density.
    Even the density of a plain old NS is near unimaginable, yet as I have already informed you, and as is mostly accepted by mainstream cosmology, the density of a large BH is near meaningless......
    Plus of course the mass that would reside at or below the Planck/quantum level, but above the classical [infinite] point singularity, is in an unknown degenerate state.
    Many people can write a scientific paper......and probably get it published without to much review or checks and balances....and that's where it stays.
    Peer review by your peers is even more important than peer review by the publishing company, which in turn depends on the reputability and respect that each publishing company endures and has earned. Some more than others....some just downright nonsensical...hence that's where it stays.
    But at least you have attempted something and even though a probable failure, I offer my congratulations on the attempt.
     
    Last edited: Apr 11, 2015
  9. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    As soon as you talk of seed BH, you are talking about subsequent accretion......But you have not answered my question, which will fritter out your objection.......What is the maximum mass of this seed BH (originally collpased BH maximum possible mass ?)

    While you answer the above, I will also suggest you ponder over certain other issues, which will force you to think, that the scenario suggested by me is not an impossibility..........

    1. We are talking about formation of NS/BH, not the accretion once the BH is formed.

    2. The SM (Schwarzschild Metric) in general referred is for the exterior to the object, thats why I asked you and that other poster, how you are accounting for the internal pressure...

    3. For the interior of the object, a different solution is present wherein equations involve the energy density / Pressure parameters which you have rightly brought in, in your previous post, subject to boundary conditions.

    4. Now if you solve these interior equations.....there is a problem, the star becomes unstable (and violates sound speed being higher than light aspect) even at R = 1.3 Rs.......so ideally the problem of violation starts as early as 1.3 Rs much before Rs.....this also gives infinite pressures (even at when core > Rs) which is not realistic...suggesting that our solution is incomplete or needs betterment...

    5. There are two distinct conditions of the star depending on the mass, one condition where NDP is overcome outside Rs and the other condition when the star is heavy and NDP is not overcome outside the Rs...........This is quite interesting...simply because EH is directly proportional to mass, so as the core mass increase the EH also increases, clearly indicating that an NS cannot form outside EH if the core mass is higher.

    6. The upper mass limit on the stable star is not around 250 Solar Mass as indicated by you, it is much higher, around half a million solar mass.

    7. The SM has problems at EH and inside EH, its a fantastic solution for r > Rc (>Rs) defining normal star and planets....but it fails at R = Rs, and may give weird results inside Rs. Almost all the other related transform solution encounter some problem or the other at r = Rs which are not realistic....

    8. Now the another untouched point : which you only raised...and I would have come a bit later, the time frame due to gravitational dilation as observed here on Earth. This can still hold for some more time.
     
  10. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Thats why the paper is here..

    Thanks..
     
  11. paddoboy Valued Senior Member

    Messages:
    21,647
    It has appeared that judgement has been passed.

    That's OK, as long as you recognise the judgement by your peers and answer all questions put to you, which you have not done.
    And be prepared to move on.
     
  12. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Is it ? I don't think. There are 3-4 major conclusions in the paper.....most of the argument was on one aspect only and that too has faced some resistance from Qreeus only, which is loosening up.......
     
  13. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Yes, I am always on move, my second paper is also ready....which has drastic yet very realistic and sensible scenario for BH......and I will surely put that too here......
     
  14. paddoboy Valued Senior Member

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    21,647

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    You think so?
    Then why not try a more reputable paper and get more notice.....or rebuttal.
     
  15. paddoboy Valued Senior Member

    Messages:
    21,647
    Best of luck...Or at least better luck with this then the other.
    Like I said......
    Peer review by your peers is even more important than peer review by the publishing company, which in turn depends on the reputability and respect that each publishing company endures and has earned. Some more than others....some just downright nonsensical...hence that's where it stays.
    I fear all this is just to gain some "much needed" online respectability after fruitless baseless arguments in many threads on this forum.
    Best of luck again.
     
  16. paddoboy Valued Senior Member

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    21,647
    I am pretty sure the Physics Nobel is going elsewhere though.

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  17. Q-reeus Valued Senior Member

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    2,606
    I'm not the one under obligation to answer such sidetrackings - especially given you still haven't answered my relevant questions from way back now. Still, let's play. Realistic stellar collapse is not neat and tidy spherically symmetric in-fall. Simultaneously highly chaotic mass expulsion and highly chaotic implosion is going on. See e.g.
    http://news.discovery.com/space/simulation-gives-new-gimpse-into-supernovas-chaotic-guts-140319.htm
    http://www.space.com/25771-big-bang-universe-supernova-simulations.html
    And you expect me to give a 'maximum seed BH mass'? He he he. No thanks.
    Already perfectly settled imo. Why play this out longer than necessary?
    Standard GR picture has no interior to EH static solution, as has been mentioned by others. Everything must move inwards. Only in imagination land do we talk of (necessarily infinite) 'internal pressures'.
    Given you posited a stable, static BNS interior to EH, I simply pointed out the contradictions and insurmountable obstacles to that being possible within GR.
    Standard picture has the limit of theoretical stability at 9/8 R_s. But you now seem to get the general picture of impossibility of stable anything 9/8 times, at, or below EH - where you claimed a BNS could sit there.
    Recall the above links to realistic simulations? Collapse involves a relatively prolonged and tortuous death struggle. For actual formation upper limit of ~ 250 solar mass, it's expected by far the most mass is outward ejected. Further, the trapped remainder is subject to massive turbulence and shock waves running through such. Conceivably multiple mini-collapses could be occurring all over the general core region before merging. And this has what to do with your postulated stable BNS at below EH?
    Really and truly?!! Here's why I think that is more fairy-tale: http://phys.org/news/2014-10-upper-limit-massive-stars.html
    http://en.wikipedia.org/wiki/List_of_most_massive_known_stars
    Now, please supply either a link(s) to a reputable refutation of above sources, or just how you personally arrived at your humungous figure ~ 2000 times higher.
    I will agree the formal maths gets weird using SM below EH, but believe it or not such is routinely done within GR community.
    Maybe the following link to an explanation involving some artful use of diagrams will satisfy you: http://mathpages.com/rr/s7-02/7-02.htm

    Now, you keep dodging my straight questions. And consume my precious time in answering your not really relevant ones. Are you at last prepared to concede that BNS is dead, given my #29 and later posts? Yes or no. If no, then my only remaining advice is to do a web search for articles on NS's by experts in that field, contact them, point them to your published article, and politely ask for their informed opinion. Brace yourself.
     
  18. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Thats a bad insinuation, from day one I am with my real name.....not many around........And I know my Physics, Maths and Engineering.................None of my arguments so far have been baseless, it is just that you do not want to understand the meaning behind...There is a difference between your approach and mine....you have a sound macro level understanding of the subject.......I dig deeper.
     
  19. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Because you only are objecting that NDP can be inside EH.......I am suggesting for core larger than 3.24 Solar Mass the NDP can only be overcome inside EH........So to establish your case you to prove that NDP cannot be inside EH due to some upper mass limit on seed BH or may be something else.


    Standard GR talks of exterior to the object....it is more suitable to the motion of the particle where BH is already formed and has established EH. The pressure figure which you have thrown in next para comes from those internal calculations only, the stage of formation of BH or star collapse.

    You are talking about infinite pressure, I have simply asked you, take even a 250 Solar Mass star and tell the forum members, how the core when of the size of EH (Rs) can create infinite inward pressure.....It cannot, the NDP stage has not yet come........And you also do not want to commit on SMBH, where the density at EH (during collapse) is air type....so where is the need to handle the infinite pressure.

    No, standard theoretically stability limit is at 4/3 Rs....but that is just the different approach, so I would go even by your figure of 9/8 Rs which is higher than Rs......So in principle a core of 9/8 Rs itself is not stable, how can you expect to get the same into Rs ?? Violating the stability conditions even outside Rs, so if you oppose anything smaller than 9/8 Rs.....then no BH too ?? You are getting to the point but you are in hurry to damn me........Not so easy, dear.


    Incorrect.....If you mean collapse once inside EH, then it is dynamic...very fast....But if you are talking about the life of star, then ok.

    No, its not fairy-tale.....It is like you telling 9 / 8 Rs as stability limit and me telling 4/3 Rs....Different concepts used to arrive at the different figures, and they can vary. You have read a paper based on luminosity which gives 150 but 260 is found out.....I can produce a paper which may be thermodynamics (or anything else) based and gives half a million solar mass.


    If something gets weird below EH, then use of that something weird to counter my not so weird concept is not the right approach. Get some better ammunition........Classical SM which you stated in your first post and wanted me to answer, gets answered by you, here itself....it gets weird inside EH....so any objection to weirdness makes no sense.


    These diagrams are derived from weirdness (your word) we get once inside EH......You know why a particle must go to singularity, simply because SM gives only one path to even to light/time that is towards r = 0. In fact time has become spatial there and there is only one direction that is r = 0.....So ideally time must stop there at r = 0 or start move in negative direction (whatever that means)....further weirdness ?? I am saying SM is wonderful for r > Rc (>Rs)...we need something else inside Rs. You cannot counter something by weirdo..



    You are not obliged to answer, you can decide to respond or not respond..........You forcefully and disdainfully declared SM/GR dead in your paper ? Then you backtracked...here you have not even reached to a stage wherein you could pose any serious objection to what I proposed leave aside declaring dead....so even the stage of backtrack by you has not even come.

    And as far as asking the experts: that will happen in due course but first why are you avoiding following question for last 3-4 posts, this will clear all objections.

    1. In the process of formation of BH (or Gravitational collapse) would the NDP be always overcome outside EH for the entire mass range ?

    (Be careful, if you answer this as per my proposition....then you will admit that at least a transient BNS is present, and after that we will discuss that transient time)

    .....You are not obliged to pursue further if you feel its not worth....but be honest (this is what you advised me).
     
  20. Q-reeus Valued Senior Member

    Messages:
    2,606
    Oh? Given that's how you see it, I have nothing further to say here. Except, be good enough to candidly report back here the unedited opinions of NS experts that do respond.
     
  21. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Incidentally there is a paper which I encountered few days back which states that the minimum mass of a BH can be around 3.2 Solar Mass....which tallies with what is calculated as 3.24 Solar Mass

    The as on date maximum observed size of the NS mass is around 1.9 Solar mass, which falls in the range 1.4 to 2.65 Solar Mass as suggested in the paper.

    The possibility of any visible Quark star etc in the range 2.65 - 3.24 Solar Mass is also proposed....very small range......none have been observed so far.

    (none objected on these otherwise equally important conclusions)
     
  22. RajeshTrivedi Valued Senior Member

    Messages:
    1,477
    Ideally a person who objects should not dodge....Pl be honest and answer the question, your objection will go away.

    1. In the process of formation of BH (or Gravitational collapse) would the NDP be always overcome outside EH for the entire mass range ?
     
  23. brucep Valued Senior Member

    Messages:
    4,098
    Your paper is an unscientific joke on this forum. You are clueless with no scholarship on the subject you think you're addressing. Think what you want. Nobody agrees with or accepts any of the nonsense you're spewing as having any scientific value. You're painting yourself as an uneducable crank with your participation in these threads. Ignorance is a choice which you seem to embrace on this subject.
     

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