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Blackhole gravity dilemma

  1. Dec 16, 2011 #1
    when massive stars run out of fuel for nuclear fusion it loses the electromagnetic outward force to negate the inward pull of gravity so gravity gets an upperhand over outward force and thus gravity jampack the rest of matter so tightly that one spoon of Blakhole matter (nuclear fusion residue) weighs 5 tons

    if this is the theory of formation of blackhole gravity must be very strong in order to cram tons of matter of former sun to the size of a planet and I'm wondering what stops earth's gravity to squish our planet to the size of watermelon

    if gravity is solely depend on mass i think people like hawking and prof kaku are exaggerating power of black hole ,i think a blackhole would be just be a half shredded compact sphere of matter composed of nuclear fission residue ,it cant gulp anything more MASSive than its mass
     
  2. jcsd
  3. Dec 16, 2011 #2

    Drakkith

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    Staff: Mentor

    The outward pressure is due to kinetic energy of the particles in the plasma, not just the EM force. Also, there is no such thing as "Blackhole Matter", as it is unknown what happens to matter that is inside the event horizon of a black hole.

    Simple. We aren't massive enough. The key to a black hole is DENSITY. Massive stars have their cores collapse into black holes and neutron stars because the final stage of fusion builds up Nickel. Since fusing nickel with itself requires energy instead of releasing it, you have a buildup of a huge amount of dense material that isn't generating energy anymore. At a certain point the nickel builds up to such huge amounts that it's gravity is simply too much and it collapses into a black hole or neutron star and generates a massive supernova. The important thing is that the density of the core increased after it produced nickel, as it cannot replace the energy released after being compressed into a smaller volume by gravity. This is the key to fusion inside stars. Initially they are powered and heated up by gravity. It is only after they have collapsed enough to heat their cores up to very high temperatures that fusion starts to happen. Once this occurs the rate of fusion reactions counterbalances gravity. If the fusion rate slows down then gravity compresses the star slightly which then causes the rate of fusion to increase to counter it again.

    This is not how a black hole works. There is no difference between a black hole and any other object other than the amount of mass. If you were to replace the Sun with an equal mass black hole nothing in the Solar System would notice. Well, other than that pesky lack of sunlight. But in regards to the gravitational field it would be the same. It is only when you get closer to the black hole that it changes.
     
    Last edited: Dec 16, 2011
  4. Dec 16, 2011 #3

    Chronos

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    There are volumes of math that assert [and constrain] the compactification of matter required to form a black hole.
     
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