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Mass of Black Holes?

  1. Sep 28, 2006 #1
    Sorry if this is in the wrong topic area but I'm really wondering this. Would there be any way to measure the mass of a black hole? This is a really interesting thing that I would like to know about. Thanks to anyone that helps!:smile:
    Last edited: Sep 28, 2006
  2. jcsd
  3. Sep 28, 2006 #2


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    Welcome to PF!

    There are many ways to measure the mass, and some are deceptively simple.

    A black hole of a given mass behaves gravitationally just like any other kind of object with the same mass.

    All you need is to do is put a test mass -- say, 1 kg lump of metal -- into orbit around the hole. By observing the lump's orbit, you can calculate the black hole's mass.

    You can also use what Nature gives you: stars. By watching the speeds at which stars orbit a suspected black hole, we can estimate the mass of that black hole.

    - Warren
  4. Sep 28, 2006 #3
    Thank you vey much for that. I've been looking everywhere and now I finally know and I can ace my report! Thanks!:smile: :smile:
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