How can a black hole be created, any model

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    Black hole Hole Model
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Discussion Overview

The discussion revolves around the formation of black holes (BH) from a classical perspective, excluding quantum effects. Participants inquire about dynamic models of BH formation, characteristic times for the appearance of a finite Schwarzschild radius, and growth rates based on initial mass density.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks an introduction to classical models of black hole formation and questions the sense of their inquiries regarding dynamic models, characteristic times, and growth rates.
  • Another participant references the Oppenheimer-Snyder model for non-rotating, spherically symmetric black hole collapse, noting that this model may not accurately represent real black hole formation due to rotation and lack of perfect symmetry.
  • The Oppenheimer-Snyder model's interior solution resembles Friedmann-Robertson-Walker cosmology, while the exterior solution is Schwarzschild, with a finite proper time to reach the singularity.
  • Realistic black hole collapse is described as more complex and still under investigation, with a suggestion to search for "Poisson-Israel" for further discussion.
  • Participants share links to resources, including animations and articles, that illustrate stellar evolution and black hole formation, with varying degrees of mathematical detail.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of classical models to real black hole formation, indicating that multiple competing perspectives exist regarding the complexity and realism of these models.

Contextual Notes

The discussion highlights limitations in the classical models, such as assumptions of symmetry and rotation, and acknowledges that the mathematical details of realistic collapse scenarios remain unresolved.

lalbatros
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I would like to read an introduction text about how BH can be be formed, with a pure classical point of view (no quantum effects).

Is there some dynamic model of BH formation?
What are the main conclusions?
Is there a characteristic time for the appearance of a finite Scharchild radius? (as seen from far away from the BH)
Is there a known grow rate for some given initial mass density?

Or do these questions have little sense?

Any comment or refences welcome.
 
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Non-rotating spherically symmetric black hole collapse is discussed in the literature in http://prola.aps.org/abstract/PR/v56/i5/p455_1 (the Oppenheimer-Snyder model, this is the Oppenheimer-Snyder paper).

This is probably not how real black holes form, because they rotate, and because they won't have perfect spherical symmetry.

The same material is in MTW pg 851 $32.4. Highlights are that the interior solution is just like a Friedmann-Robertson-Walker cosmology, while the exterior solution is Schwarzschild. The proper time to reach the singularity is finite. There are some gif movies of this process and some discussion at http://casa.colorado.edu/~ajsh/collapse.html#collapse

I recall some online homework sets that discussed this problem as well, but I couldn't find them.

Realistic collapse is a lot more complicated, and is still under study. Do a search for "Poisson-Israel" for some discussion.
 
This looked pretty good, Lalbatros:

http://outreach.atnf.csiro.au/education/senior/astrophysics/stellarevolution_deathhigh.html

I would recommend you watch the "movie" if you haven't already before you start reading the text. IMHO the rotating material looks awfully like water going down a plughole! I'll check out the one pervect posted (thanks pervect} and if it's different I'll see if I can dig up the one I was looking at.

Edit: the one I was looking at last week isn't the one pervect posted. The collapsing material was coloured brown, and the rotation flattened it and threw it around. But darn, I can't find it. I'm at work so I'll have to go now. This one didn't work too well on my PC:

http://www.nasa.gov/centers/goddard/universe/swift_multimedia.html
 
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