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Black hole parameters

  1. Nov 17, 2008 #1
    Ive taken a general relativity course and in it we learned about how black holes are characterized by the parameters of mass, angular momentum, and charge. I have some questions about other parameters though.

    1) Can a black hole have a vibrational parameter? This would really only be applicable in a rotating black hole, where the singularity is a ring rather than a point. It seems to me that some massive object could cause vibrations in this ring by exerting a greater force on the close end than on the far end. Even if this scenario isn't the explanation, can black holes vibrate? And if so, what are the modified equations using this vibration?

    2) In a frame of reference that is moving relative to a black hole, does the black hole appear differently? i.e. are the equations describing the black hole modified at all? Since the relativistic mass gained by the black hole is not uniform in all directions (I recall seeing a picture of an ellipsoid to describe it), it seems like the black hole might appear differently in a moving frame and Id be interested to see the limit of this difference as the speed approaches c.

    3) Are there any other parameters of black holes besides mass, angular momentum, charge (and possibly vibration and speed)?
     
    Last edited: Nov 17, 2008
  2. jcsd
  3. Nov 18, 2008 #2
    None is known..but I wonder if mass, charge and momentum are purely theoretical limits??

    Charge remains constant, momentum and mass should reflect different observed velocity

    I have read repeatedly thats all!! But you might also count the entropy displayed on the event horizon area "discovered" by Beckenstein and Hawking...and temperature can be infered from the usual three characteristics. But if any information leaks out via radiation...no consensus, I don't believe. Also, Strominger and Vafa started new string theories...many additional studies since...additional information maybe can be stored and recovered from constituent branes....

    I don't believe black holes have even been experimentally proven, but there is lots of evidence..it is strong, but indirect.....is it conclusive?? Given that we have no complete theory inside the event horizon, QM and GR breakdown, I'd not be surprised if other things are discovered.
     
  4. Nov 18, 2008 #3
    well the reason Im asking is to determine if there any any additional properties that could affect temperature and entropy. I have seen a few equations of the form dM = TdS + phi * dQ + omega*dJ ... (where the ... is included to include any additional parameters). However I have never seen any explicitly defined additional parameters.

    Also, the black body radiation of a black hole does not provide any extra information. The radiation is a function of the temperature, which is a function of the parameters of the black hole (mass, charge, spin).

    As for velocity, I was really wondering if it would change the shape of the singularity, or of the event horizon (not just the observed mass).

    Also, Im talking about the theoretical black holes predicted by GR here, not whatever might exist in reality.
     
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