Infinite Gravity of a Black Hole(or not)

[IResnick]

In the center of a black hole sits it's singularity. An infinitely dense point. I question, because this singularity is said to be infinitely dense, then shouldn't it's mass be infinite as well. Well this cannot be so, seeing that gravity is based on mass and distance, and we are not currently being sucked into a black hole. But imagine that this black hole does have infinite mass. We could expect that distance between us and black holes would regulate this much gravity, but even lessening infinity is impossible. Thus, there would have to be some sort of energy or force that regulates this gravity and keeps it at bay. SOmething that breaks the laws of physics that we know of. Howhever this is all speculation, seeing that we will never know the explaination of "infinite" density until we venture into a black hole.

[MigL]

If you take a gram of something and compress it to within its Swartzchild radius, it will be a microscopic black hole.

If you take a ton of something and similarily compress it, it will also be a ( slightly bigger ) micro black hole.

If you compress a star ten times the size of our sun, it will be a black hole.

None of these masses are infinite !

[pavelcherepan]

In the center of a black hole sits it's singularity. An infinitely dense point. I question, because this singularity is said to be infinitely dense, then shouldn't it's mass be infinite as well. Well this cannot be so, seeing that gravity is based on mass and distance, and we are not currently being sucked into a black hole. But imagine that this black hole does have infinite mass. We could expect that distance between us and black holes would regulate this much gravity, but even lessening infinity is impossible. Thus, there would have to be some sort of energy or force that regulates this gravity and keeps it at bay. SOmething that breaks the laws of physics that we know of. Howhever this is all speculation, seeing that we will never know the explaination of "infinite" density until we venture into a black hole.

 

The fact that density appears to be infinite is just the sign that it's the extent to which General Relativity is applicable. Obviously, as you correctly pointed out the density can't be infinite as it would imply infinite mass which is not true. So there is something we don't understand, maybe it will be solved with Quantum Gravity, maybe M-theory, but definitely some update to out theories is needed.

 

On the side note - there is a theoretical description of the black hole in superstring theory that doesn't feature singularities. See <Fuzzball>.

[Endy0816]

Should actually be an undefined density(Finite Mass / Zero Volume). Note that present scientific thought is leaning away from singularities having any real existence.

[ajb]

The mass of a black hole is defined as that observed by a far away observer. The question of the mass of a singularity is a bit moot from this perspective. As far as we know, the mass of a black hole will always be finite in accordance with the laws of physics.