Black Hole Singularities

  • Thread starter Labguy
  • Start date

A Black Hole "singularity is:

  • A point of infinite mass and density

    Votes: 1 11.1%
  • A sphere of finite size and density

    Votes: 3 33.3%
  • A ring as per Kerr/Newman

    Votes: 0 0.0%
  • Not necessary to be defined as "singularities"

    Votes: 5 55.6%
  • More than one above

    Votes: 1 11.1%

  • Total voters
    9
  • #1
Labguy
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Main Question or Discussion Point

Just checking current thought.
 
Last edited:

Answers and Replies

  • #2
I got 100%, did I win?

Just viewed the poll results, everyone agrees with me, 100% is the poll result for what I picked as the answer.

Yahooooooooooooooooo!

I picked the second one, finite size and density. Infinity is an "inconcievable" so pick that one, and admit to 'fooling yourself'
 
  • #3
marcus
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Hi Labguy,
I am much in favor of checking current thought, as you say,
on this and other things. I notice that you do not
include the possibility of finite mass with infinite density
(that is, finite mass and zero volume).

I will try to guess after I have thought a little----certainly
do not know the answer right off!

Do we really know what singularities are?
String theory is far from proven----isnt even complete yet.
The classical GR geometry is probably just an approximation
to a quantum geometry picture of a singularity, that perhaps
does not yet exist in anyone's mind?

This is very puzzling.

Anyway congrats on posting an interesting poll!
 
  • #4
LURCH
Science Advisor
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Well, I suppose calling it a "singularity" means that it has infinite density by definition, but I'm guessing that "correct definition of the word" is not what you were asking. "Finite mass with zero volume" is what "singularity" means, but for reasons related to time dilation, I don't think true singularities exist.

I chose "Not...Defined...".
 
  • #5
Labguy
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Originally posted by LURCH
Well, I suppose calling it a "singularity" means that it has infinite density by definition, but I'm guessing that "correct definition of the word" is not what you were asking. "Finite mass with zero volume" is what "singularity" means, but for reasons related to time dilation, I don't think true singularities exist.

I chose "Not...Defined...".
A. I agree.
B. Me too.
 
  • #6
marcus
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Originally posted by LURCH
Well, I suppose calling it a "singularity" means that it has infinite density by definition, but I'm guessing that "correct definition of the word" is not what you were asking. "Finite mass with zero volume" is what "singularity" means, but for reasons related to time dilation, I don't think true singularities exist.

I chose "Not...Defined...".
Well I voted for "not necessary to be defined as singularities"
but I would certainly appreciate some more discussion.
Not sure what comfort time dilation gives to one unfortunate to fall into a black hole. May he not encounter all the nastiness
we may reasonably expect and conclude that it is a true singularity. Please provide some detail.
 
  • #7
LURCH
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Originally posted by marcus
Well I voted for "not necessary to be defined as singularities"
but I would certainly appreciate some more discussion.
Not sure what comfort time dilation gives to one unfortunate to fall into a black hole. May he not encounter all the nastiness
we may reasonably expect and conclude that it is a true singularity. Please provide some detail.
Oh yes, all the nastiness would be there. There would be the heartbreak of falling beyond a point from which one could not return, and the ripping in half (such an inconvenience) and all that goes with it. But the use of the term "singularity" implies that the mass at the center of the BH occupies a single point in spacetime. The mass would have dimensions of "zero" in all directions, and that's what I think will be prevented by time dilation.

As you've probably heard, time dilation (according to most BH models) would keep an infalling victim from ever reaching the center. If this model is correct, then the same phenominon should keep the original collapse of the central mass from ever reaching the exact center. As it shrank, time would proceed more and more slowly, causing the final moment before reaching a state of true singularity to take forever.

Of course, at the Event Horizon, things would proceed much more normally. So the rate at which Hawking Radiation removes mass from the BH would eventually equal and then greatly exceed the rate of collapse. This would theoretically result in the reduction of the BH mass to less than three Solar Masses (at which point it should no longer be a BH) long before the central mass reaches true singularity.
 
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