How singularity in black hole works?

[Eren]

Hey everyone,

So, we know black hole has a singularity in middle of itself and it has infinite mass and no volume. But why we saying that? And if it has infinite mass on one point why it doesn't have infinite gravity? If so, why not everything going inside it?

[MigL]

Infinite density, not infinite mass, and so, no infinite gravity.

The mathematical solution is singular, the 'reality', most likely not.

[Strange]

5 hours ago, Eren said:

But why we saying that?

It is based on an extrapolation of what general relativity says. But we are fairly sure that a theory of quantum gravity is needed to provide a more realistic description. It is almost certain that the singularity has no physical meaning/existence. 

[Sensei]

6 hours ago, Eren said:

So, we know black hole has a singularity in middle of itself and it has infinite mass and no volume. But why we saying that?

Only layman can say so. Black hole has no infinite mass, no infinite volume (one could ask for how many dimensions Universe you are talking about.. ?), no infinite density...

If it would have infinite mass, it would suck in the entire Universe..

 

Black holes are categorized by their mass. f.e. BH inside of some galaxy is typically the most massive object.

BH is made of particles that have been sucked in during its lifetime.

Newly born BH, after supernova explosion, has smaller mass than previously existing star that exploded. Because mass has been ejected from it in the all directions, just core collapsed.

 

 

 

6 hours ago, Eren said:

And if it has infinite mass on one point why it doesn't have infinite gravity? If so, why not everything going inside it?

Did you read any scientific article about some black hole.. ? f.e. they mention "black hole with mass XXX Sun masses joined with YYY Sun masses together and we know it because of gravitational waves we just detected"...

 

[beecee]

6 hours ago, Eren said:

Hey everyone,

So, we know black hole has a singularity in middle of itself and it has infinite mass and no volume. But why we saying that? And if it has infinite mass on one point why it doesn't have infinite gravity? If so, why not everything going inside it?

The singularity is the realm at which our current theories fail or are not applicable. A singularity need not be infinite but may lead to infinite quantities of spacetime curvature and density, mass certainly is not one of them. Most physicists do not believe the singularity exists, (other then that as defined where our current theories break down) which means a surface of sorts of matter/energy in some unknown state should exist at around the quantum/Planck level.

[Endy0816]

Density = Mass / Volume 

Hypothetically in the center you have a finite Mass with Zero volume. The term "mathematical singularity" sums it up better now, as we don't know if this what actually occurs. Someday someone will figure out a more descriptive Theory, until then we can wonder.

Black holes can be massive, but ultimately still limited in how much gravitational force they can produce. Does make for a very impressive and much more active accretion disk though. 

Otherwise yes, we would all be heading down the proverbial drain

Edited October 7, 2017 by Endy0816