black hole question

[hoola]

I heard Kip Thorne say that the matter falling into a black hole gets completely destroyed. If gravity can exist essentially on it's own, and no longer requires the matter which created the field, presumably having converted all matter energy into gravitational energy, is there any thinking on how to build a black hole directly, with some process needing no mass to "get it started", but by directly manipulating space ? If the black hole horizon is the place that virtual particles separate, could some induced "splitting" of a single virtual particle pair mimic some properties of a microscopic BH?

[mathematic]

"is there any thinking on how to build a black hole directly, with some process needing no mass to "get it started", but by directly manipulating space ?"

 

No.

[MigL]

Matter gets 'destroyed'.

Mass/energy doesn't, it is conserved.

[ajb]

All the matter that falls into a black hole will reach the singularity in finite proper time. What happens then is just not understood. Nor is the final state of a black hole after evaporation. Black holes really do push our understanding of space-time and seemingly simple questions are not yet answered.

 

As a side remark, Kip Thorne is here in Warsaw this week. I may bump into him tonight...

[hoola]

his remarks seemed to indicate there was no interior, and if so, no singularity. It seems as though once a large gravitation field gets established, matter is not needed to sustain the field.

[Strange]

his remarks seemed to indicate there was no interior, and if so, no singularity. It seems as though once a large gravitation field gets established, matter is not needed to sustain the field.

 

I believe that is possible, in principle, because the gravitational field itself has energy. I'm not sure it can happen in practice. As far as is known, black holes always contain the mass that created them.

 

I don't think anyone thinks that singularities actually exist.

[MigL]

The property 'mass/energy' which previously belonged to the ingested matter, becomes a property of the event horizon, after ingestion.

What, if anything, is 'inside' the Black Hole has very little to do with it.

[hoola]

in considering the analogy to the electric field, which is ordinarily thought of as needing some associated material substrate in the macro world, but on the microscopic level the electron whirling around a nucleus doesn't have any carrier entity, and appears as a free agent....in considering black hole interiors, don't virtual particles appear everywhere, including that region? Why wouldn't they and if they did, how would that environment affect them? I suppose it would matter where within the interior they appeared. Doesn't the center of a BH have gravitational neutrality analogous to you standing in a hollowed out region at the center of the earth and being weightless? If so, they would separate at the horizon and there only, and be less affected if appearing either towards the center, or away into surrounding space?..Of course, what about dark matter? Wouldn't that get stuck in the field and contribute to overall field strength? If so, wouldn't the overall parameters of a BH need to include the dark matter contribution? Twin holes with identical geometric size might have identical overall masses, but the dark matter contribution could vary between them, so they wouldn't be truly identical. From what I have read about dark matter and it's lack of self interaction, it can never manifest into a BH by itself, and become a "dark black hole"...

Edited November 22, 2015 by hoola

[MigL]

Electric charge ( and ang. momentum ) are also conserved by the event horizon.

That doesn't mean that the mass is actually localized in the spherical ( mathematical ) shell defining the event horizon.

The horizon conserves the information.

So even inside the horizon you will still reach the centre as its the only thing in your future.

 

And dark matter interacts gravitationally.