Black hole inside a larger black hole.

  • Context: Graduate 
  • Thread starter Thread starter Meatbot
  • Start date Start date
  • Tags Tags
    Black hole Hole
Click For Summary

Discussion Overview

The discussion revolves around the concept of a smaller black hole potentially existing within the event horizon of a larger black hole, exploring theoretical implications and scenarios. Participants examine the nature of black holes, event horizons, and gravitational interactions, with a focus on both theoretical and conceptual aspects.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants propose that a smaller black hole could orbit a larger black hole, questioning the implications of such a scenario.
  • Others argue that as black holes approach each other, their orbits become nonlinear, leading to merging rather than stable orbits.
  • A participant suggests that a swarm of stars could exist within its own Schwarzschild radius, potentially allowing for a black hole to be part of this configuration.
  • There is a discussion about the definitions of event horizons, with some participants noting that the standard definition may not apply to inner bodies within a black hole.
  • Some participants assert that concepts of time and space lose meaning inside a black hole's event horizon, while others challenge this view, suggesting that they remain meaningful except near the singularity.
  • One participant raises the issue of how a black hole could be perceived from within another black hole's event horizon, introducing the need for different coordinate charts.
  • There are references to gravitational time dilation and the effects of mass both inside and outside a black hole, with implications for the nature of black holes in such configurations.
  • Some participants express caution regarding assumptions about the creation of a common event horizon from multiple black holes, noting a lack of supporting theorems.

Areas of Agreement / Disagreement

Participants do not reach a consensus; multiple competing views remain regarding the nature of black holes, event horizons, and the implications of one black hole existing within another.

Contextual Notes

Discussions include limitations related to definitions of event horizons, the stability of configurations involving multiple black holes or stars, and the applicability of Schwarzschild solutions to non-empty black holes.

  • #31
hurk4 said:
Unless someone is inside a BH??

Look at the reply, post #6, by xantox.
 
Space news on Phys.org
  • #32
Doesn't the universe satisfy the conditions of Almanzo's postulated star cluster inside its own schwarzchild radius? If so then every black hole is within the event horizon of a larger black hole. cf

http://www.mathpages.com/home/kmath339.htm
 
Last edited by a moderator:
  • #33
The orbital velocity at the event horizon is the speed of light.
Your black hole cannot orbit inside the event horizon of the other black hole because it cannot go faster than the speed of light. It instead falls in and does not orbit.
 
  • #34
Haelfix said:
The problem with having a black hole inside a black hole is several fold.

Xantox is right, there is a problem with the horizon definition.

Worse, there is a problem with the asymptotics. The asymptotics of the interior black hole/star solution does not have minkowski space as a limit, so the very metric itself is poorly joined. In fact, it has some god awful time varying thing as an asymptote.

The problem has indeed been looked at before, and its apparently one of the most excruciatingly complex things to do numerically in all of physics. The last time I talked with someone about it (I believe the state of the art is in Germany), they're still in rarefied extremal D != 4 situations with a bunch of highly technical assumptions which would take a specialist to explain, and even then, the computer returns junk most of the time.

Any references to their work?

Excuse me bumping this thread.
 

Similar threads

Undergrad Question on halos of matter made from massive and stable particles?
  • · Replies 53 ·
2
Replies
53
Views
6K
Undergrad Why didn't the Big Bang form a Black Hole?
  • · Replies 7 ·
Replies
7
Views
3K
High School What happens to information inside a black hole?
  • · Replies 4 ·
Replies
4
Views
905
High School Questions about the Eddington Limit and Super - Eddington black holes
  • · Replies 0 ·
Replies
0
Views
2K
Undergrad Seeking Visualization Tools for Hypothetical Black Hole Concept
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Falling into a massive black hole is not necessarily noticeable
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Does Hawking Radiation Cause Black Holes to Evaporate?
  • · Replies 24 ·
Replies
24
Views
3K
Undergrad Black Hole Diameter: Is It Finite or Infinite?
  • · Replies 36 ·
2
Replies
36
Views
7K
Undergrad DeSitter cosmological horizon stability?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Brian Cox and the end of the Universe?
  • · Replies 13 ·
Replies
13
Views
6K