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From what I understand, the mass of a black hole should be nearly infinite, how much more massive can something get?

  • Is the name to be literally interpreted such that a Supermassive Black Hole just has more mass?
  • Or rather, is a Supermassive Black Hole just a regular Black Hole with nearly infinite mass that is larger in diameter?
  • If the difference is in fact a change in diameter, how are the changes in size with the retention of the immense mass reflected in the Supermassive Black Hole's gravitational field?
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The density is infinite - not the mass, IIRC. –  Undo the Snowman Sep 24 '13 at 20:04
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Just the supermassive :P –  Afzaal Ahmad Zeeshan Nov 7 '13 at 15:54
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The density at the singularity is believed to be infinite. Typically a black hole's size is defined by it's event horizon, so it could be considered to have a finite density. –  Aaron Jul 6 at 10:20
    
Have to agree with Aaron. And add that, since we don't know what goes on inside a black hole, we can hypothesize that it's a sort of mini-universe. And perhaps our own universe may be a black hole inside some other universe... –  Rodrigo Jul 17 at 15:36

4 Answers 4

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Stellar mass black holes form from the collapse of massive stars at the end of their lives. You can then find them scattered throughout galaxies, just like you find massive stars. They typically have a mass a few times the mass of the sun.

Supermassive black holes are found at the centers of galaxies. They typically have mass of millions of Suns.

Recently they have started to discover Intermediate Mass Black Holes which blur the lines between a stellar black hole and supermassive black hole. The typically have a mass in the range 100 to one million solar masses.

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I have heard Black Holes described as a "Single point of immense mass in space," does this hold true, or are there Black Holes of varying diameter? –  David Freitag Sep 24 '13 at 20:07
    
They vary in diameter. What you're referring to has to do with the effects of the laws of physics breaking down once you pass the event horizon. –  John Conde Sep 24 '13 at 20:09

The mass of a black hole is not infinite. In fact, if a black hole is created that is big enough to survive evaporation, its mass will be its starting mass, plus any mass swallowed up, minus the radiation that leaves it.

Which is why you hear phrases such as "A black hole with ten times the mass of our sun" or in the case of a supermassive black hole, "...of millions of suns"

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Stellar mass black holes and supermassive black holes likely form from very different mechanisms. While we have a pretty good idea how stellar mass black holes form, we're still not sure about how supermassive black holes form because they occur very early on in the Universe.

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Black Holes do not have infinite mass; they have presumably infinite density at the point of singularity. The mass of the black hole plays a large role in the diameter of the event horizon (the sphere where escape velocity required exceeds the speed of light. The 'black' part.)

A supermassive black hole, as you suggested, just has more mass; It has a lot more mass than a stellar mass black hole. Supermassive black holes are usually at the center of galaxies and can have gravitation influences across the entire galaxy, while stellar mass black holes will have the gravitation influence of the size of the former large star they formed from.

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