Black Hole.... Not so Black

Discussion in 'Astronomy, Exobiology, & Cosmology' started by RajeshTrivedi, Oct 1, 2014.

  1. tashja Registered Senior Member

    Messages:
    715
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. OnlyMe Valued Senior Member

    Messages:
    3,914
    Good responses tashja.

    Both made clear reference to the theoretical aspects of the discussion and the fact that the discussion centers on physics that we just don't know with any certainty.

    I would have preferred had Prof. Hamilton, when he included mention of the Schwartchild case, he had included, that it is a simplified solution and equally theoretical, though I believe that is implied. Many of these lay discussions don't always come across as understanding, the theoretical significance and limitations of simplified solutions...

    I think the way Prof. Carlip began setting the stage, as theoretical or unknown, was a far better approach for a lay oriented response.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. paddoboy Valued Senior Member

    Messages:
    21,225

    I echo those remarks tashja, and once again many thanks for your efforts and both the good professors in their time in replying.
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
    You don't get it... A true singularity in the context means...independent of coordinate systems used........It is no body's case that this is synonyms with real singularity or interacts with anything beyond Rs...It is right that this solution is useful simplification of EFE...but what is amiss is that you have shown certain ignorance about the word..true singularity...not coined by me.. despite using EFE so casually in all three last posts...
     
  8. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
    Tashja,

    Thanks a lot, you have great rapport and resourcefulness to organise these responses at very short notice..my salutations !!
     
  9. RajeshTrivedi Valued Senior Member

    Messages:
    1,366

    Paddoboy,

    below is extract from prof Carlip response....

    In classical GR, "the Planck scale" doesn't mean anything -- it
    is a scale that explicitly involves Planck's constant. But
    classical singularities are predicted to occur at zero size and,
    typically, infinite curvature and density, which is certainly
    smaller in size and larger in energy than any quantum scale.


    This concludes that this singularity per say has no link with Planck's scale.
    Yes it is true that QGT as and when it comes may settle the singularities
    possibly even at Planck's level..But till
    then these singularities cannot be associated with Planck's scale..

     
  10. OnlyMe Valued Senior Member

    Messages:
    3,914
    What does true mean? You are responding now to the following comments, redacted for simplicity,

    When you added the word true to the statement quoted above, it added an underlying assertion of reality, to an otherwise accurate statement. Using the word true, without the clarification in your current post, does add an impression of reality.

    It seems very often, at least part of the conflict in these discussions, originates with a lack of clarity that does not always get resolved, before the conflict takes on a life of its own.
     
  11. OnlyMe Valued Senior Member

    Messages:
    3,914
    You left out the first sentence of his comments, which is important...

    Prof. Carlip:

    As usual for a question regarding quantum gravity, the most accurate
    answer is, "We don't know."

    Excluding that signle introductory statement, makes the part you did quote out of context and subject to misinterpretation.
     
    KilljoyKlown likes this.
  12. paddoboy Valued Senior Member

    Messages:
    21,225
    No, you are twisting and mangling what basically all the Professors said.
    You have been wrong so many tims in this thread now, that I have lost count. Please don't make me go back and show the world that.
    Three points you should consider in what Professor Hamilton said.....

    Prof. Hamilton:

    "One thing can be said for sure: general relativity fails at
    singularities. In the Schwarzschild case, general relativity
    cannot continue geodesics past the singularity".

    Tell me Rajesh, where does GR fail?
    Let me tell you. It fails at the Planck/Quantum level.
    So, next question....Where does the Singularity as defined by the Professor, begin?
    Let me tell you. It begins at the Planck /Quantum level.

    "The reaction of most theoretical physicists is that some other theory,
    presumably a quantum theory of gravity, must replace general relativity at singularities. Surely physics cannot simply end at singularities".

    Heavens to Betsy!!! Quantum, GR and Singularities all mentioned in the same sentence.

    Please Register or Log in to view the hidden image!



    "And most physicists would argue that quantum gravity becomes
    important at the Planck scale. In the Schwarzchild case,
    the spacetime is empty,"


    And now the Planck scale and Qunatum gravity!!! When will it all end!!!
    And of course the other mention of "spacetime is empty in the Schwarzchild case"
    Which highlights another of your misconceptions about BH's and density, and my answer that a BH is just "critically curved spacetime" with the Singularity at the middle.



    It's been nice doing business with you Rajesh.

    Please Register or Log in to view the hidden image!

     
  13. paddoboy Valued Senior Member

    Messages:
    21,225


    And left out the last sentence....
    " So for now, we don't know".

    Steve Carlip
     
  14. paddoboy Valued Senior Member

    Messages:
    21,225

    You mean you finally accept what I have been saying all along??
    Or, and I'm sure the good Professor would agree.....push the need for the Singularity back further into the abyss.
    And I'm sure now with my previous post, that you do realise that the QGT which may eliminate or push back the Singularity, begins where GR leaves off.


    You keep saying that...Are you playing silly buggers?
    What do you mean by associated with?
    My claim is that the Singularity begins where GR leaves off, and that is at the Planck/Quantum level.
    Another important fact I also mentioned earlier a few pages back. The Singularity is in itself not infinite in any quantities. It can though, and may lead to Infinite quantities and status.
    But just as the big boys have said, and I also concur, I don't believe this will be so.
     
  15. KilljoyKlown Whatever Valued Senior Member

    Messages:
    6,493
    I think we still don't know enough about galaxies to claim any such thing. I say if it doesn't have a BH core it's not a galaxy, but only a star cluster. I'm sure when galaxies collide not all the stars are going to be captured by the newly forming galaxy and those escaping stars will still become drifting star clusters or rogue stars drifting in between galaxies.
     
  16. KilljoyKlown Whatever Valued Senior Member

    Messages:
    6,493
    Again I think you are getting confused about mass and matter. We consider normal matter to be atoms. Atoms are mostly empty space so whatever mass they contain is very spread out. The only way we know of to compress matter is with gravity. The following quote is from Wikipedia.
    There are many stages of degeneracy pressure that occur during different levels of gravitational collapse. In white dwarf stars only the electrons are squeezed down close to the nucleus. In neutron stars the electrons are absorbed into the protons where the charges cancel eachother out and they become neutrons. Now the neutrons are also mostly empty space (that's kind of hard to imagine for many people), but as the degeneracy pressure continues to increase, it is speculated that the matter may have a quark fluid state. That has never been observed. But the point is in my opinion that matter continues to reach new stages of degeneracy even when it has receded beneath the event horizon of a newly formed BH. I do not believe small BH's are fully compressed to the same extent as large BH's are. We have no way to observe what happens on the other side of an event horizon, but I can see no reason to believe the mass of a small BH is just as compressed as the mass of a SMBH.
     
  17. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
  18. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
    This is what I said in my post # 188, long before professors' quote...

    """"Let the QGT come, as of now it makes no sense to push back the singularity, it is either your imagination or picked up from some source here and there. It is like adding 1 to x/0.......


    Is it any different from above ?? Why are clinging to this aspect that too when we don't know much about QGT..

    Your stand was that Singularity is at Planck's level...My stand was that there is no business between singularity and Planck's level as on date...I do not think any of the good professors have stated that singularity is at Planck's level......

    Now stop using abusive language.......and relax...the sky has not fallen.........
     
  19. paddoboy Valued Senior Member

    Messages:
    21,225
    Rubbish, all you have done within this thread, is rail against accepted BH theory, on many aspects as I have previously listed....and never once admitting your error of judgement or stupidity. This has finalised in the most recent attack on accepted mainstream thinking in regards to the fact that a BH Singularity, [and the BB Singularity] both begin where GR fails, and that is at the Planck/Quantum level.


    I'm pushing back nothing. I'm just claiming any future validated QGT may either eliminate or push back this Singularity.
    All others so far have understood this, why havn't you?


    In that case you are Ignorant of what they have said.
    Again, I'm telling you, that GR fails at the Planck/Quantum level, and that then invokes the Singularity.
    And all professors, one way or the other, plus all our contributors here so far have aligned with that.
    You lack the intestinal fortitude to admit you are grossly in error of your railing against this and other accepted mainstream data.



    You mean in reference to me observing your twisting and mangling of accepted theory, and doing your damdest to get out from under, and escape your many errors with some dignity in tact? The truth may hurt, but it is best confronted.
     
  20. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
    I fully agree with you on this observation.. I attempted to make my position clear many a times...Paddoboy refused to commit himself even on specific pointer by me...his response was more of generalistic in nature...
     
  21. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
    Ignoring your abuses...I will try once more keeping the same context...

    GR fails at singularity (at r = 0)...What does this failure have to do with Planck Level ?? Question is very pointed and precise, so please do not beat around the bush...stick to the point and do not link QGT which is yet to get established.

    You unilaterally claim that other than stupid me, every one on the forum has understood you on this point....It is my appeal to all those who agree with Paddoboy on this point to respond. My assertion is very simple that this failure of GR at singularity has nothing to do with Planck's level...thats what Prof Carlip also says...

    Prof Carlip...
    ....But classical singularities are predicted to occur at zero size and,
    typically, infinite curvature and density, which is certainly
    smaller in size and larger in energy than any quantum scale....



     
  22. paddoboy Valued Senior Member

    Messages:
    21,225
    That's a lie and just couples with your other lies in attempting to get out from under. Again I'm telling you that where GR ends or fails, is where the Singularity begins, and that just happens to be at the Planck/Quantum level.

    You could not even accept the fact that once any mass reaches its Schwarzchild radius/limit, further collapse is compulsory and inevitable to Singularity status, where GR fails, and the Planck/Quantum realm start.

    Just a quick reminder to try and alleviate your railing against mainstream BH data......
    "Prof. Hamilton:

    One thing can be said for sure: general relativity fails at
    singularities. In the Schwarzschild case, general relativity
    cannot continue geodesics past the singularity.

    The reaction of most theoretical physicists is that some other theory,
    presumably a quantum theory of gravity, must replace general relativity
    at singularities. Surely physics cannot simply end at singularities.

    And most physicists would argue that quantum gravity becomes
    important at the Planck scale. In the Schwarzchild case,
    the spacetime is empty"


    That excerpt from the Professor's reply, actually rebukes at least three silly unsupported assumptions you seem erroneously afflicted with.
     
  23. RajeshTrivedi Valued Senior Member

    Messages:
    1,366
    Answer the new question....What does this failure have to do with Planck Level ??

    you evaded the earlier one..
     

Share This Page