Black Holes .

Discussion in 'Astronomy, Exobiology, & Cosmology' started by river, Aug 11, 2019.

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  1. river

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    You will
     
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  3. DaveC426913 Valued Senior Member

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    Post 112. I answered your question about "what a black hole is made of".
     
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  5. paddoboy Valued Senior Member

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    Correct. There is no reason why BH's are not partly or completely made of DM.
     
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  7. river

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    A singularity is a purely mathematical construct .
     
  8. DaveC426913 Valued Senior Member

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    No. They re not made of any "type" of matter.

    Per post 112:
    This is what is meant by "black holes have no hair". Black holes can be completely characterized by only three externally observable classical parameters: mass, electric charge, and angular momentum. It is meaningless to ask "what kind of matter makes up a black hole".
     
  9. DaveC426913 Valued Senior Member

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    Sure. Whatever is at the centre of a black hole, our current math does not describe it. We call that the singularity.

    And there is no reason to think it might have a tunnel to anywhere.
     
  10. river

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    Disagree

    The Black Hole is the essence of all galaxies .
     
  11. DaveC426913 Valued Senior Member

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    You can disagree all you like; it doesn't add credence to your unfounded ideas. Put down the UFO book and pick up a basic science book.

    What does this statement have to do with anything?
    I mean, it's wrong, but why even mention it?
     
  12. river

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    But here is the thing ;

    Mathematics didn't include the physical .
     
  13. DaveC426913 Valued Senior Member

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    This statement is meaningless.

    The black hole, being spherical, has a centre point. That's simple geometry.
    We do not have a theory about what happens there, since it involves gravitational pressure beyond what GR covers, so its physics is unknown.

    But there is no reason to suppose there is a "tunnel to somewhere else" there any more than there is reason to suppose there is a tiny unicorn there.
     
  14. paddoboy Valued Senior Member

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    Well, yes I agree..That was put rather poorly, and I did think he was referring to a singularity as defined by infinite curvature and density. That definition and the infinite density and curvatures, has been generally rejected now
    Hmmm. I am certainly familiar with the "no hair" concept and the three parameters that can be used to describe a BH, mass, charge and angular momentum. But nothing can stop a BH from swallowing DM I would have thought. It may certainly react different to baryonic matter, in that baryonic matter will heat up and radiates light...not so with DM. Are we on the wrong page?
    https://www.space.com/8080-black-holes-gobble-dark-matter.html
     
  15. paddoboy Valued Senior Member

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    BINGO!!! That is what I was trying to say!!! No excuses other then my footy team is playing and its difficult to type and watch TV together.

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  16. DaveC426913 Valued Senior Member

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    Agree.

    My point is, once DM falls into the BH, it loses its identity. Same with any other type of matter. The information about what kind of matter it was before it fell in is gone from the universe forever.

    That is why river's question 'what kind of matter is a BH made of' makes no sense. A BH is not "made of" any kind of matter; it is only mass (and charge and spin).
     
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  17. paddoboy Valued Senior Member

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    So, what's different?

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  18. DaveC426913 Valued Senior Member

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    Most elliptical galaxies do not have black holes at their centres.

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  19. river

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    And Space .
     
  20. river

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    Why not ?
     
  21. James R Just this guy, you know? Staff Member

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    You've been answered many times. I previously gave you an answer.

    I told you that black holes form from collapsing stars. So, those black holes are "based on" star-stuff - their mass is the mass of all that hydogen and helium and stuff that fell in.
     
  22. DaveC426913 Valued Senior Member

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    Because your assumption, below, is faulty:
    Black holes are not the essence of all galaxies.
     
  23. DaveC426913 Valued Senior Member

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    I am trying to avoid giving river the impression that black holes are "made" of matter. They're not.
    Anything that falls into a black hole (normal matter, dark matter, antimatter, etc.) loses its identity forever. A black hole does not contain matter; it only contains mass (and charge and spin).
     
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