Black Holes .

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

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  1. river

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    So your saying that our galaxy , the centre of our galaxy , has no black hole within it .
     
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  3. DaveC426913 Valued Senior Member

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    He is not saying that.
    Our galaxy does have a black hole at its centre. A supermassive one of a bout 6 billion solar masses.
    It was formed by the gobbling of millions of stars over our galaxy's lifetime.
     
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  5. river

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    What is the essence of the black hole ?

    To your last statement ;

    Why ?
     
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  7. DaveC426913 Valued Senior Member

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    What do you mean by essence? That's not a very scientifically well-defined term.

    For me, the essence of a black hole is compactified mass.

    Why what?
    Why was it formed by gobbling millions of stars?
    Science does not attempt to answer 'why' questions. That's for the philosophers.
     
  8. river

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    What started the " gobbling " of stars ?

    What is the essence of this " gobble " ?
     
  9. DaveC426913 Valued Senior Member

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    Likely a supergiant star ran out of fuel and collapsed on itself.
    Without the outward force of radiative pressure, any star larger than about 3 solar masses will collapse into a black hole.

    Gravity, friction and collisions.
     
  10. river

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    To your second last statement ; gravity based theory .
     
  11. DaveC426913 Valued Senior Member

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    Not sure what part you think is theoretical.
    We certainly know gravity exists.

    And we certainly know black holes exist. Here's one now:

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    And we certainly know that black holes are both massive and compact, meaning gravity very close to them is very strong.
    We observe this.

    Here is an image from the centre of the Milky Way:

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    We know how massive the central object is, based on the period of the orbits of the stars nearby.
    We know how small it must be, based on the closest approach of the stars nearby.
    We know of no known material that can be that dense without it collapsing on itself.
     
    Last edited: Aug 18, 2019
  12. river

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    To your last statement ;

    A three dimensional material .
     
  13. DaveC426913 Valued Senior Member

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    All materials are three dimensional.
     
  14. river

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    Indeed
     
  15. DaveC426913 Valued Senior Member

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    And they're not strong enough to withstand gravity of that magnitude. Thus: black hole.
     
  16. river

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    So three dimensions turns into two dimensions because of gravity .
     
  17. DaveC426913 Valued Senior Member

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    What? No.
    Where do you get 2 dimensions from?
     
  18. James R Just this guy, you know? Staff Member

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    Did I write that somewhere?

    No, I did not.

    Stop trolling.
     
  19. James R Just this guy, you know? Staff Member

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    Stop trolling.
     
  20. paddoboy Valued Senior Member

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    That fact has been obvious for years now, and is why I ignore this troll, who isn't interested in learning one iota.
    Rightly or wrongly, the first person I have ever ignored on this or any other site.
    It was made blatantly painfully obvious when he was previously banned from the sciences, so when I contributed articles or comments on mainstream science, he would cunningly and deceitfully, start another in the fringes on the same subject, simply so he could do his usual trolling and ignorant denial and that same particular issue.
     
  21. davewhite04 Valued Senior Member

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    What is trolling?
     
  22. davewhite04 Valued Senior Member

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    The Sun is a planet. Do you think a straw has a hole?
     
  23. DaveC426913 Valued Senior Member

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    The sun is not a planet.

    That is.
     
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