I saw the term spinning black hole popping up everywhere so my question do spinning black hole behave similarly to say a planet where it bulge in the equatorial and compress at the poles? what fundamental force is causing the bulging because in the case of planet it is the electrostatic force?

  • $\begingroup$ Equatorial bulging of rotating planets is not from electrostatic force. $\endgroup$ – G. Smith Dec 28 '18 at 6:16
  • $\begingroup$ @G.Smith: I meant to say that when planet spins the momentum is carry away to the equator by electrons $\endgroup$ – user6760 Dec 28 '18 at 6:18
  • $\begingroup$ No, it isn’t. Where did you get that idea? $\endgroup$ – G. Smith Dec 28 '18 at 6:43
  • $\begingroup$ @G.Smith: binding energy is result from gravitational force and when planet spin there is a centrifugal force pushing outward and this force transfer from atoms to atoms via electrostatic force no? I know it is the inertial but I can't visualize that. $\endgroup$ – user6760 Dec 28 '18 at 6:46
  • $\begingroup$ Electrostatic repulsion between atoms keeps the planet from collapsing under gravity. Is that what you're talking about? But to calculate the equatorial bulge due to centrifigual force, you don’t have to think about inter-atomic forces. $\endgroup$ – G. Smith Dec 28 '18 at 6:54

The angular momentum of a Kerr or Kerr-Newman black hole causes the event horizon to have an equatorial bulge. It emerges from solving the Einstein field equations for gravity and has nothing to do with any of the other three fundamental forces.

You can picture it as being similar to the bulging of a rotating planet due to centrifugal force.

  • $\begingroup$ I thought is was ringularity because point cannot spin so obvious I was deeply mistaken. $\endgroup$ – user6760 Dec 28 '18 at 6:29
  • $\begingroup$ Point particles can have angular momentum in the form of quantum spin. $\endgroup$ – G. Smith Dec 28 '18 at 6:32
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    $\begingroup$ The angular momentum of the black hole is simply equal to the angular momentum of the matter and radiation that first creates and later falls into the hole. Angular momentum must be conserved. $\endgroup$ – G. Smith Dec 28 '18 at 6:36

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