Black hole questions

[EdwardRo]

TL;DR

Random blackhole questions.

To start off, please understand that as much as I love physics and try to keep myself immersed in everything, my education in it doesn't extend past high school courses. I'm aware that I have a lot of holes in my knowledge and understanding, so please be gentil with me.

Today I was watching an episode from the world science festival on YouTube about black holes. I was letting the information mull around in my brain when I realized a few things...

1. Has anyone ever tried to build a black hole from the inside out?
I come from an engineering background, and sometimes you need to build things in reverse to get them to work.
What if you started at the plank length, determine the maximum amount of mass/energy that could be contained in that space. Then you can expand that out to cu mm, cu cm, cu m. That would then give you the minimum size the singularly would be.

2. If we imagine the singularly as a sphere, could there be a space within it where the gravity of the outer "crust" and inner core balance out? This could potentially create a zone within the singularly itself where it is re exposed to normal space time.
I'm thinking that if yes, then this could help explain the information paradox created.

Are these valid lines of thought? Where are the holes in my understanding?

 

[Ibix]

1. Has anyone ever tried to build a black hole from the inside out?
I come from an engineering background, and sometimes you need to build things in reverse to get them to work.
What if you started at the plank length, determine the maximum amount of mass/energy that could be contained in that space. Then you can expand that out to cu mm, cu cm, cu m. That would then give you the minimum size the singularly would be.

Classically, a black hole can have any size. There's a minimum mass for one to form by stellar collapse, because smaller stars don't leave enough mass in their remnants to collapse under their own weight, but smaller black holes (including microscopic ones) that formed in the early universe have been hypothesised. We've never seen evidence of them, though.

The singularity doesn't have a size. It's a breakdown of the model and lies outside the manifold, which is the entity that provides notions of things like size. We assume a working theory of quantum gravity will explain what actually happens where classical gravity fails.

2. If we imagine the singularly as a sphere,

The singularity is more like a moment in time than a place in space. It isn't anything like a sphere.

 

[Ibix]

2. If we imagine the singularly as a sphere, could there be a space within it where the gravity

On a re-read, are you using "singularity" and "black hole" as synonyms? They're not the same thing. The singularity is inside the black hole, but it is not all of it.

could there be a space within it where the gravity of the outer "crust" and inner core balance out?

Nothing we are aware of can stop gravitational collapse once neutron degeneracy pressure is overcome. Black hole interiors are vacuum as far as we know - everything that enters them hits the singularity in short order and nothing can stop that.

 

[PeterDonis]

Has anyone ever tried to build a black hole from the inside out?

You can't, because a black hole is not made of anything you can build something from. A black hole is just spacetime geometry. It's not made of parts.

 

[PAllen]

Well I can think of a recipe for building one Just start accumulating cold iron filings in one place, continue till you’ve added about 2 to 3 solar masses. Voila, it will collapse to a black hole.