Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Another Black Hole Question

  1. May 21, 2008 #1
    Hello all,

    I was wondering if anyone could answer this question and I apologize if it's a rudimentary question but, is there a maximum size that a black hole can get to? Given an infinite amount of mass, would it ever reach a point where it could grow no larger, at least from a mathematical stand point. I realize something like this is damn near impossible to observe but I was wondering if the equations pointed to any wacky happenings once a certain size is reached.

  2. jcsd
  3. May 21, 2008 #2
    From the "standard" theories regarding black holes, they can always get bigger. There isn't infinite mass in the universe, and if there was - it would be a huge conservation of energy violation, so its hard to even look at it theoretically.

    I know little to nothing about the details regarding non-standard theories, but i seem to recall hearing that in string theory (because the center has a finite size) there is an upper mass limit... but i can't even imagine what they'd claim would happen if you surpassed that limit. Not sure about that.
  4. May 22, 2008 #3
    They recently have found a correlation between the mass of a galaxy and the mass of the black hole within it. Accordingly you would find the largest possible black holes inside the largest galaxies. If a black hole is rapidly spinning however there may be a lower limit to their size. If say two of the largest sized galaxies were to merge it would not be unlikely that eventually their black holes would also merge. Would the resulting huge black hole be unstable? different theories would have different answers.
  5. May 22, 2008 #4


    User Avatar
    Science Advisor
    Gold Member

    A black hole already tips the scale for maximum density permitted by modern physics. Size become irrelevant once a singularity [black hole] forms. Gargantuan black holes have already been detected in other galaxies. Some are believed to be many billions of solar masses in size.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook