Black holes (split from Is it possible to change the spin of a proton?)

[lucks_021]

A thing that I want to know, using this topic which comes to this subject, is:

If in a singularity, the time passes so slowly that for us (out of it) it would be infinite (since the singularity has infinite density) how can we observe the effects of the black hole angular momentum? (if you don't understand something, please ask me, my english isn't good)

[Strange]

11 minutes ago, lucks_021 said:

A thing that I want to know, using this topic which comes to this subject, is:

If in a singularity, the time passes so slowly that for us (out of it) it would be infinite (since the singularity has infinite density) how can we observe the effects of the black hole angular momentum? (if you don't understand something, please ask me, my english isn't good)

It is at the event horizon, not the singularity that time dilation becomes infinite. I guess we could determine the angular momentum of a black hole by looking for evidence of frame dragging affecting the orbits of things near the event horizon. We are a long way from being able to do that, however.

(You should really have started a new thread for your question.)

[lucks_021]

7 minutes ago, Strange said:

It is at the event horizon, not the singularity that time dilation becomes infinite.

But the singularity isn't "inside" of the event horizon? And I was thinking that the event horizon is just the limit which the light can "scape" from the black hole, and if its right, this place (event horizon) does not suffer the same time alteration in comparison with the singularity. (I may have been confused by the concepts)

20 minutes ago, Strange said:

(You should really have started a new thread for your question.)

Sorry about that, if more people reply I can start a new one.

[Strange]

10 minutes ago, lucks_021 said:

But the singularity isn't "inside" of the event horizon?

Yes. Although, as Markus said, there singularity doesn’t exist except as a mathematical artefact because we don’t have a theory that describes what happens. 

12 minutes ago, lucks_021 said:

And I was thinking that the event horizon is just the limit which the light can "scape" from the black hole, and if its right, this place (event horizon) does not suffer the same time alteration in comparison with the singularity. (I may have been confused by the concepts)

Because we are causally disconnected from the space inside the event horizon we can’t compare the rate of time inside and out.