BLACK HOLES Tutorial based on observations and GR

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Sep 9, 2015.

  1. paddoboy Valued Senior Member

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    The renowned astronomer Arthur Eddington called them a cosmological absurdity.
    GR and its equations predicted their outcome, yet Einstein originally thought that there would always be a physical barrier to prevent such catastrophic collapse.
    John Michell theorised BH of sorts as far back as the late 1700's while working on collapsed star densities and mass. He called them "Dark Stars" but was not really taken seriously and his work was pigeon holed until many years later when Neutron stars were discovered and questions were asked about further possible collapse of stellar objects.

    When a star uses up its available fuel for fusion, it has one of three paths to take, based on the original mass of that star. It can end up a White Dwarf as our own Sun will eventually see out its life. These WD's are held up from further collapse by EDP [Electron Degeneracy Pressure]
    Larger mass stars finish their lives as Neutron/Pulsar stars, held up from further collapse by NDP. [Neutron Degeneracy Pressure]
    Inevitably even larger mass stars are monstrous enough to overcome both EDP and NDP, and forming what was to be known as Black Holes. First known as Gravitationally Completely Collapsed Objects, John Wheeler coined the BH.

    Simply put a BH's EH [Event Horizon] is where the escape velocity equals "c" the speed of light in a vacuum.
    Beyond this point nothing can escape, including light.

    A BH's size can vary from those predicted to have occurred at the BB, microscopic quantum sized BH's, to stellar collapse BH's a few 10s of kms in diameter, and the monsters that lurk at the centers of galaxies ranging from millions to billions of solar masses. These are termed Super Massive BH's.
    BH's can only have three properties of mass, charge and angular momentum. Charge would obviously be quickly negated, leaving mass and angular momentum.
    Angular momentum also would gradually be negated, but over much slower rates.
    This leaves the end state of all BH's as the Schwarzchild variety, or a BH with no spin or charge, also the most mathematically convenient to work with.
    If we were to categorise all the BH's we have in our Universe today, the most common would be the Kerr BH, or the one with angular momentum, first suggested by Roy Kerr.

    GR tells us that once any massive object is forced to undergo collapse, once it reaches a point called the Schwarzchild radius [which for a BH is the EH] then further collapse is compulsory. This means that if we squeeze the Sun into a volume of around 5 kms, it would reach its Schwarzchild radius, further collapse would continue and it would become a BH.

    The Schwarzchild radius is the radius of a sphere such that, if all the mass of an object were to be compressed within that sphere, the escape velocity from the surface of the sphere would equal the speed of light. An example of an object where the mass is within its Schwarzschild radius is a BH. Once a stellar remnant collapses to or below this radius, light cannot escape and the object is no longer directly visible, thereby forming a BH. It is a characteristic radius associated with every quantity of mass. The name itself results from Karl Schwarzchild a German astronomer, who calculated the exact solution during the first world war in 1916.

    This compulsory collapse leads us to what we refer to as the Singularity. Mathematically speaking, the Singularity is where all our known laws, including GR break down, or are not applicable.

    Many other seemingly weird aspects of BH's are known, but as weird as they are, they are aligned with the facts borne out by SR that space and time are not absolute and that all frames of references are as valid as each other. An example of one of these seemingly paradoxical scenarios is as follows......
    If myself and a companion travel towards a BH and I stay a safe distance away, while my curious friend travels on towards the BH and its EH, due to gravitational time dilation, I will from my position in space, never see him cross the EH to his doom, only slowly and gently just be redshifted beyond my instrumental viewable ranges.
    From my friends point of view though, he proceeds towards the EH, and crosses it with no changes from his perspective in time, ignoring tidal gravitational effects which depend on the BH's size...the smaller the BH, the more critical and soonerwill be the effect of spaghettification as it has become known.

    Physically speaking the Singularity lies at the heart of the BH, and is where all its mass is concentrated in a form that as yet we have no description for.
    It lies at the quantum/Planck level of spacetime, and may in the future have more light shed upon it by a validated QGT [ Quantum Gravity Theory]
    Is there a surface of sorts there or does it lead to infinity? WE do not as yet know, but the QGT should help sort that out.

    A quantum effect called Hawking radiation which theorises on particle pair creation at near a BH's EH, where one escapes and the other succumbs to the BH, tells us that over the lifetime of the Universe, BH's should evaporate.
    Hawking radiation though, just like BH's have never been observed.
    Though we still have some that will claim that BH's do not exist, none can ever describe the effects on matter/energy and spacetime, that are observed in any other logical scientific way, the effects that can only ever be attributed to BH's.
    BH's for all intents and purposes, and based on the current laws of physics and GR, most certainly do exist.
    Likewise Hawking radiation, and what we know about the quantum world, tells us that logically it is a real concept, but in most cases, would be only evident over the lifetime of the Universe, and we are talking time frames of many hundreds and even trillions of years.


    Stephen Hawking once used a phrase from a poem by Dante, about the gates of Hell.
    "Abandon all hope ye, that enter here" probably aptly describes a BH.
     
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  3. paddoboy Valued Senior Member

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    I thought that the above "tutorial" was necessary particularly in light of some of the false information that is sometimes circulated on forums such as this.
    It is of course totally in line with what accepted mainstream cosmology claims, and was written by myself more than a decade ago on the long defunct ABC forum.
    The only additive was the 6th paragraph which I obtained from WIKI, to highlight further the GR defined Schwarzchild radius.

    I have not posted it to be questioned re those that are pushing any alternative aspect. It's simply the accepted mainstream notion we have on BHs at this time.
    If I have inadvertently made any error with regards to how BHs are pictured and accepted, please point that error out.
    Otherwise it's for discussing this awesome scenario of both Newtonian and GR cosmology.
    What I did fail to mention re the John Michell Newtonian Dark Star model, is that the compulsory collapse does not apply. In other words the surface of the star exists at the point where the escape velocity equals "c"
    Naturally Einstein and the success of GR saw it as the more obvious alternative.
     
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  5. The God Valued Senior Member

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    Generally a Tutorial is to be given by a person who has good practical and/or sound Theretical Knowledge of the subject. Hope you do. Nontheles its a good try. Let see point by point what it offers....

    Many people, including mainstream scientists, still find them absurd and improbable.


    Hmm. Fuel (if you can call that) is always there. There is one more stage before WD can form. For a star the Gravitational Pressure is Hydrostatically balanced by the fusion energy, but beyond Iron the fusion needs energy, it is no longer exothermic, causing stability issue and continued collapse till EDP/NDP as the case may be.


    Cite, pl? Those predicted to have occured at BB?

    Obviously? How it will be negated? what is 'quickly' time frame? Cite pl.

    How? 'Gradually' time frame? how do you say much slower rates? Who takes away? Cite pl.

    Most Mathematically convenient to work with.

    Thats ok, but science does not look for mathematical convenience. Approximations or simplifications should be reasonable and pragmatic, then only they are proposed.

    Can you refer a table wherein populationwise BH categorization is given?

    The simple fact is that the Kerr BH is an exact solution.


    Around 3 Kms will be more prudent..

    Well, I would say Belly Button instead of Heart. For SCHWARZCHILD BH you can always say the center of the sphere of radius EH.

    Cite, Pl.

    None can ever......is an incorrect representation of the fact. rather use of word 'ever' is bad.

    Actually SGR A (Star), our own BH at MW center is not required to explain the orbital motions of many stars around. The motion of these stars (S2 etc) can be described by an alternative mass distribution regime, but the stability of such a system is an issue, so BH solution wins over. The catastrophic failure of predictions about G2 cloud while approaching SGr A (Star), has certainly put a dent about the understanding of this monster down there.


    Certainty about existence of BH...can be taken with a pinch of salt. Can you cite any reference which uses the word certainty while talking about existence of BH?



    Just thought that those who read this tutorial should get a limited but right perspective.....Goood attempt by the OP.
     
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  7. paddoboy Valued Senior Member

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    What your thoughts on my rights to title this a tutorial is of really no interest or relevance to the tutorial. It already was evaluated by an expert GR theorist on an old forum.
    What your thoughts are as to the articles validity is of also no concern to me for a few reasons, not the least being that you have already been refuted on relevant topics twice now in recent times, ignoring at this time the complete refutes of all past issues re your unconventional and invalidated thoughts on BH's.
    And of course I certainly made it clear enough that I wasn't interested in discussing alternative hypothesis, and that this was accepted mainstream and previously reviewed theoretical applications of BH's
    here....
    I have not posted it to be questioned re those that are pushing any alternative aspect. It's simply the accepted mainstream notion we have on BHs at this time.
    If I have inadvertently made any error with regards to how BHs are pictured and accepted, please point that error out.

    What I did inadvertently leave out, is that any questioning on what I have said, should be done by a reputable mainstream scientists/physicist.
    Apologies for that.
    You have yet to answer any questions about your own expertise, and coupling that with the fact that you tend to be stupidly pedantic on some points [tutorial] and plain wrong on others [3kms and BH's volume with regards to Sun.] I will chose not to play your game at this time.
    Of course if you will reveal your credentials then I may reconsider.

    Otherwise my tutorial stands as theoretical factual according to mainstream cosmology despite your games, which I'm not playing.
    I will comment on one error I made though with regards to
    With regards to......
    Though we still have some that will claim that BH's do not exist, none can ever describe the effects on matter/energy and spacetime, that are observed in any other logical scientific way, the effects that can only ever be attributed to BH's.
    none can ever, should be "none has ever"


    I'm sure most who have already read this see it as correct, since it has already been up for a week.
    Let me state again categorically that until someone is able to come up with a validated method to how spacetime and matter/energy are affected to such critical degrees, then BH's remain pretty certain applications of mainstream cosmology.
    And let me again state also that all your "questions/pedant/nonsense " are all answered realistically without any need for pseudoscientic applications like Black Neutron Stars.
    Have fun!

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  8. paddoboy Valued Senior Member

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    21,647
    It may seem as if I'm being rather hard on you, but I'm just being brutally honest.
    Besides revealing your credentials [if any] for me to offer you anymore, you could also link to any reputable source to support your stance,
    If you can overcome your aversion for mainstream links, and show something reputable to support your take, then I'll of course will reconsider.
    I won't hold my breath though.
     
  9. The God Valued Senior Member

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    3,546

    G = 6.67408 × 10-11 m3 kg-1 s-2
    Solar Mass M = 1.9891 × 10^30 kilograms
    Light Speed c = 299 792 458 m / s

    r = 2GM/c^2 = 2.95 km.....well around 3 Kms.

    So, will you correct your tutorial on this ?
    Try responding on other points raised, you will have to correct/add on each and every point raised.

    Rest all is usual song and dance by you, does not require any further comment.
     
  10. paddoboy Valued Senior Member

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    21,647
    Again that's not what I said...perhaps english is your second language...
    what I said.......
    This means that if we squeeze the Sun into a volume of around 5 kms, it would reach its Schwarzchild radius, further collapse would continue and it would become a BH.
    Which means that squeezing the Sun into a volume of around 5kms [which obviously would be the diameter] would mean a Schwarzchild radius of around 2.5 kms.

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    Obviously now going on your past "Modus operandi" that will be the last we hear of this fabricated illusion of yours, without any recognition of your error and stupidity...

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    I don't need and I'm not going to respond at all for the reasons given. But I'll give you a hint....your other usual thoughts/ideas/ hypothesis are as far out of whack as the one I have just kindly resolved for you, and are in line with the same thoughts as our past troll rajesh.
    All you need to do is reveal your credentials or supply a link supporting your nonsense.
    Otherwise the Tutorial stays as correct as given until someone of reputable expertise shows otherwise.
     
    Last edited: Sep 15, 2015
  11. brucep Valued Senior Member

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    4,098
    Really bad attempt by you. You should consider not running your mouth until you understand the physics. Ohh you think you do. LOL. Here's evidence of the dying pulse train predicted by GR. One of my favorite confirmation of a prediction derived from GR. Generally unknown by cranks. It's the one that falsifies the recently discussed ether theory of gravity.
    http://hubblesite.org/newscenter/archive/releases/2001/03/text/
    This is from 2001.
     
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  12. paddoboy Valued Senior Member

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    21,647

    Notice how he argues against mainstream accepted BH cosmology. [just as rajesh did] Notice how he refuses to recognise or use any reputable links [just as rajesh did] Notice how stupidly pedantic he sometimes is [just as rajesh was] Notice how he questions the most simplest things like a BH with charge and how the charge is negated,

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    [just as rajesh did]
    See any resemblance?
     
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  13. The God Valued Senior Member

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    3,546
    You are fooling none, but yourself. Anyway, I grant that, now please correct your tutorial and make it 6 Kms in place of 5, and also restructure the statement so that it appears that you are talking about diameter..You still have to give citations on how and where and in what time charge and angular momentum vanishes.
     
  14. The God Valued Senior Member

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    Your posts appears to be misplaced.

    I have expressed no opinion in the post, I just observed a few damning mistakes in the tutorial, and wanted the OP to give citations, which of course he failed so far.
     
  15. paddoboy Valued Senior Member

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    Who's fooling who around here? Wanna put it to a vote?
    I'll stick with the 5 , it's a reasonable approximation despite your obvious stuff up in trying to claim it as an error.
    My Tutorial stays as is because it is correct.
    Of course you could ask another reputable expert to judge.
    Again, let me put it to you in no uncertain terms, All you need to do is reveal your credentials or supply a link supporting your nonsense.
    to gain any credibility and to have me officially deride your supposed corrections in my tutorial and many mistakes and errors in your questionings and silly presumptions thereof.


    Again...
    [1]What are your credentials to question mainstream cosmology?
    and [2] What reputable links do you have to support your nonsense?

    The balls in your court.
     
  16. paddoboy Valued Senior Member

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    21,647
    No, no mistakes and you are not qualified to question any tutorial which is based on mainstream cosmology.
    But keep trying...
     
  17. The God Valued Senior Member

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    You are continuing with a big song and dance, please explain what is so obvious about charge negating, how and why it vanishes, and the time frame....You claimed all these points in the tutorial. rajesh understood or not I do not care, but do you understand what you are talking about? if yes, then answer, instead of dancing around. Once you answer this, you can take up angular momentum as well.
     
  18. paddoboy Valued Senior Member

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    You are an obvious fraud, [just as rajesh was] and I'm not playing your games.
    The tutorial is correct as most on the forum that know more than you seem to agree.
    Oh, and I'm enjoying the song and dance at your expense my friend.

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  19. The God Valued Senior Member

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    If you say that reasonable approximation of 2.95 X 2 = 5.9, is 5 and not 6, then I have nothing more to say. I close my argument with you on this point.
     
  20. paddoboy Valued Senior Member

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    21,647
    Whether you close your argument or not is neither here nor there.
    You don't run this forum my friend and neither did rajesh much to his disdain.
    His problem of course was that he was an arrogant self gratuitous individual who was totally unable to admit when he was in error...much like yourself.
    Again my tutorial stands as correct, as the forum members obviously seem to agree, and your agenda laden nonsensical questions will not be answered by me until you comply with what I have asked.
    Alrighty?
    Oh, and I'm still enjoying the song and dance at your expense.

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  21. paddoboy Valued Senior Member

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    Ummm just like rajesh you attempt in vain to confuse.
    I didn't mention 2.95 as the Schwarzchild radius. My only reference was squeezing the Sun to within a 5km volume then its Schwarzchild radius [the point at which further collapse becomes compulsory] would be reached.

    Perhaps my friend if you stopped carrying on with what you are attempting to carry on with, and approach my posts and threads in an unbiased manner, you would not make the stupid errors and misinterpretation you have on this question and some of your other questions which also border on ignorance in the extreme. eg: Why a BH with charge will see that charge negated.
    rajesh also had a problem with that, in fact rajesh in his stupidity, could not even accept that any BH can only have three properties...mass, charge and spin. It's called the "No Hair Theorm" and was coined by Roger Penrose from memory. But you can check on that also as I'm not a 100% sure...96.5%??? yes.
    Perhaps I can ressurrect those threads for you?

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  22. The God Valued Senior Member

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    Just by the way, let us see what is 'Song & Dance"...copied from the free dictionary

    1. an extended, often self-justifying explanation that may be irrelevant or untrue.
    2. An excessively elaborate effort to explain or justify.
    3. An elaborate story or explanation intended to deceive or mislead.

    keep singing and dancing, please, be my guest.
     
  23. The God Valued Senior Member

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    Do this forum a favor, ask any member, any member of this forum or sub forum, who will agree to this 5 Kms / 6 Kms topsy turvey by you.......then you can ask any member who can explicitly vouch for the contents of the tutorial....None you will get on both the counts.


    I will tell you something, since you stated that this tutorial was approved by a GR expert. If an expert reads this, he will immediately come to know that it is written by an over enthusiast who lacks formal knowledge of the subject. Now he has two options either a. rubbish it or b. smile & move away. The expert chose the later. I had time so I thought I could get you corrected. But as some one said, you are 'uneducable'...you gave me no reasons to disagree with him.
     

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