Black Holes .

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

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  1. DaveC426913 Valued Senior Member

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    Look, black holes have got to be one of the simplest things in all of nature.

    Forget event horizons and forget singularities and the other stuff.

    Mass creates gravity. This is fundamental.
    More mass creates more gravity.
    That's it. That's all.

    Add enough mass, and gravity crushes the matter together until it's super dense.
    You can just keep adding mass (because that's what gravity does).

    An atom consists of electrons in orbitals around a nucleus. Those orbitals have a lot of force keeping them going, but it's not infinite.

    If you add enough mass, the pressure literally overwhelms the force keeping the electrons in their orbitals, and they get crushed into the nucleus. You get a mass of just neutrons. Just a solid ball of neutrons, all packed, touching together.

    Neutrons have a lot of force keeping them as neutrons, but that too is not infinite.

    Add more mass, and the pressure overwhelms even the solid structure of a mass made of neutrons packed together.
    The neutrons themselves collapse.

    Here's the kicker: We don't know what happens to matter when it gets crushed down from a neutron to something smaller.

    But we know it happens. Gravity is relentless.

    A black hole is nothing more than that. It's what happens when so much mass is crushed together that it overwhelms the forces that keep atoms ... as atoms.

    That's it. That's all there is.


    When we talk about the singularity, all it means is this: we don't know what matter looks like when its crushed smaller than an atom. We don't have the physics to describe it yet. That's all it means.

    But rest assured, we know the collapse of matter does happen. It has happened. The simple process of accumulation of matter leads to collapse and, once started, is inevitable. We have models describing how it happens, even if those models stop short of the end-product. And we now have pictures, proving that all our science up to this point was borne out by nature.

    It's as simple as that.
     
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  3. paddoboy Valued Senior Member

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    James has already labeled this fool a troll. As far back as post 8 Dave said....
    and further along another answer.......
    Adding to Dave's excellent rundowns....
    [1] When a star exhausts all its available fuel, we have three possible results, depending on the mass of the star...[a] Stars around our own Sun's size, end up as White Dwarfs...incredibly dense degenerate matter held up from further collapse by EDP [Electron Degeneracy Pressure] Larger mass stars are able to overcome EDP but are held up by further collapse by NDP [Neutron Degeneracy Pressure] [c] The largest of the stars at the end of their lives, are able to overcome even the NDP and form BH's.

    [2] When the collapse reaches the Schwarzchild radius of any given mass, further collapse is compulsory, and so the mass collapses to a singularity.

    [3] GR though fails us at the quantum/Planck level, and so we cannot reasonably speculate on the state of the matter at that region.

    [4] Most physicists today, reject the singularity as defined by infinite spacetime curvature and density [or the mythical point singularity, rather they simply accept a singularity as defined where GR and the laws of physics desert us, that is the quantum/Planck level.

    [5] If that is correct, and if the singularity of infinite qualities does not exist, then its reasonable to assume a surface of sorts, at or below the quantum/Planck level.

    [6] We in actual fact can never extract or observe anything below the EH [where the escape velocity equals "c"] and are only able to come to the reasonable assumptions above, if GR is viable and valid, and we have no reason to expect it isn't.
    :::::::::::::::::::::::::::::::::::::::::::::::::::

    So we have operating here either a troll, a totally ignorant person, or a liar. Take your pick.
     
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  5. river

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    So no Galaxy has a BH at its Galactic Core ? Just stars do .
     
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  7. paddoboy Valued Senior Member

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    Even long before Einstein, the concept of matter collapsing under gravity was researched by John Michell and "Dark Stars" were hypothesised where the surface escape velocity equals "c"
    Unlike the GR type BH's this EH was a surface without any reference to a Schwarzchild radius, which tells us that once reached, further collapse is compulsory...and there we have the GR type BH.
     
  8. river

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    Galactic cores , have no BH , at their core .

    What form of matter is the Schwarzchild radius based on ?
     
    Last edited: Aug 29, 2019
  9. paddoboy Valued Senior Member

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  10. James R Just this guy, you know? Staff Member

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    Nobody wrote that. Stop trolling.

    Our galaxy, for example, has a black hole at its centre.

    Nothing. A radius isn't a substance, it's a measure of length.

    It's about time you explain what you mean by "based on", too. So, please make sure you do that before you post anything else on this subject. I thought I'd already answered your question about what black holes are "based on", a couple of times, earlier in this thread, and in my opinion other posters have too. If you think that question hasn't been answered, you need to explain what's wrong with the answers you were given.
     
  11. Janus58 Valued Senior Member

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    Many do, some don't. There is more that one way to form a BH. You have stellar BHs formed by the collapse of massive stars which run about 10 solar masses or so. You can have supermassive BHs which formed from a huge collection of mass during the early evolution of a galaxy. It is also hypothesized that conditions early in the universe could have produced small or "quantum" BHs . The last type is the only one for which we don't have evidence for ( at least not yet)
    It isn't based on any "type" of matter, it is based on the idea that If you have enough mass contained within a sphere with this radius, an event horizon forms, The amount of mass needed goes up with the radius. Everything has a Schwarzchild radius, but only BHs have all their mass contained within it. The Earth has one, and it is just a bit under 1 cm. The Earth isn't a BH because the vast majority of it mass is outside of this radius and the amount of its mass inside the radius is not enough to form a BH with a event horizon of that radius. To make a BH out of the Earth, you would have to squeeze it down until it's density is in the range of 2 x 10^30 kg/m^3 ( for comparison, the present density at the Earth's core is ~ 13,000 kg/m ^3)

    What "form" this mass takes makes no difference, even light crossing event horizon will contribute to the mass of the BH.
     
  12. river

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    This avoidance of an explaination towards galactic core BH is concerning . All responses focus on stars not the galactic core . Why is that ?
     
  13. davewhite04 Valued Senior Member

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    Limited knowledge.
     
  14. river

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    Is that an agreement with my statement above ?
     
  15. davewhite04 Valued Senior Member

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    Yes, I didn't think you felt that strong about it, but good for you!
     
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  16. river

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    But its not true . Images or otherwise .

    Matter is not crushed by gravity , gravity is one of the weakest forces in Nature .

    Matter is three dimensional , all matter is .

    All matter circulates . Rotates . Not only atomicly but in the macro . As by the image shown .

    Rotation is confined by the magnetic field .

    It is the magnetic field along with rotation by this mass that causes this BH illusion .

    Otherwise , what came first , the dark hole or the mass ? In the image ?
     
    Last edited: Aug 31, 2019
  17. DaveC426913 Valued Senior Member

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    You may be a little confused here. The galactic core has a black hole at its centre. That black hole started as a star that collapsed.
    The back hole at the centre of our galaxy is the same as any stellar black hole. It just happens to have gathered a lot of mass because the galactic core is so dense with material.
     
  18. davewhite04 Valued Senior Member

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    You're working within the confides of the scientific blueprint which change all the time thanks to people who think outside the box.
     
  19. DaveC426913 Valued Senior Member

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    In fact, it is.

    Gravity of a single atom is very small. But gravity is much mre far reaching than the other forces - and it is cumulative.
    Ten atoms have ten times more gravity than one atom.

    Ten thousand trillion trillion trillion trillion atoms has 10^52 tiems more gravity. That's about the size of a large star.


    What does this have to do with the price of tea in China?

    No necessarily true. But so what?

    Are we still talking about "all mass"?

    What illusion?

    Mass was there before it collapsed into a black hole.
     
  20. river

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    So BB started with just stars ?
     
  21. DaveC426913 Valued Senior Member

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    Indeed. And the people who change it are people who are educated in science.

    You have to know what the box is before you can think outside it.
     
  22. DaveC426913 Valued Senior Member

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    No. Why are we talking about the Big Bang? We were talking about back holes.
     
  23. river

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    Indeed

    So what is the singularity based on ?
     
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