From every angle, what is the complete shape of a black hole?

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Discussion Overview

The discussion explores the shape of black holes, considering various perspectives on their geometry and appearance from different angles. Participants examine theoretical models, visual representations, and the influence of surrounding matter such as accretion disks.

Discussion Character

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

Main Points Raised

  • Some participants propose that black holes have a spherical event horizon, while others suggest they may appear as 2D circular voids depending on the observer's frame of reference.
  • There is a discussion about the influence of accretion disks on the perceived shape of black holes, with some arguing that these disks could alter the appearance from a spherical to a more complex shape.
  • One participant mentions that rotating black holes might create different visual effects, potentially leading to a perception of rotation from the observer's perspective.
  • Concerns are raised about the theoretical nature of singularities within black holes and how this complicates accurate modeling of their shapes.
  • Some participants express curiosity about the possibility of using computer simulations to visualize black holes from all angles, questioning the current understanding of their physics.
  • There is mention of the potential for black holes to appear slightly stretched at the equator due to spin and surrounding matter.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the exact shape of black holes, with multiple competing views and uncertainties remaining about their geometry and visual representation.

Contextual Notes

Limitations include the dependence on theoretical models and the unresolved nature of singularities, which complicates the understanding of black hole shapes.

Astroboy123
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Is it shaped like a tornado, or a sphere, or is it flat like a disk? If there was a way to view a black hole, dimming the brightness around it to get a clear look, what would be its full shape if you could view all around the outside of it from every possible angle?
 
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Astroboy123 said:
Is it shaped like a tornado, or a sphere, or is it flat like a disk? If there was a way to view a black hole, dimming the brightness around it to get a clear look, what would be its full shape if you could view all around the outside of it from every possible angle?

This is an interesting question. From outside it would resemble a black 3d sphere rather than a "hole". However most black holes are actually bright at a distance due to the matter which consists of the accretion disk.

This is my current understanding but I am sure you will get some more feedback from more knowledgeable PF members.
 
Astroboy123 said:
Is it shaped like a tornado, or a sphere, or is it flat like a disk? If there was a way to view a black hole, dimming the brightness around it to get a clear look, what would be its full shape if you could view all around the outside of it from every possible angle?

Black holes have a spherical event horizon however they can be surrounded by accretion discs or in the case of rotating black holes you can get an http://en.wikipedia.org/wiki/Rotating_black_hole" .
 
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ryan_m_b said:
Black holes have a spherical event horizon however they can be surrounded by accretion discs or in the case of rotating black holes you can get an http://en.wikipedia.org/wiki/Rotating_black_hole" .

Rotating Universes are also the theoretical environments required for naked singularities. Which is very interesting - although these have never been observed and are theoretical only.

I think black holes would appear to the observer as 2D circular void - it would not have any dimension other than 2D from FoR of the observer? It would just look like a completely black "hole" and if you could move around it at relatavistic speeds in any direction (outside of the EH) it would look as if the "hole" were rotating with you. This is assuming the BH has no large accretion discs, can anyone advise if the disc is a disc in the traditional sense or a
3D envelopment?

I just imagine a void, with total information exchange breakdown - almost like a pre-universe void; like the opposite of the Big Bang... Maybe too many sci fi books!
 
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Cosmo Novice said:
Rotating Universes are also the theoretical environments required for naked singularities. Which is very interesting - although these have never been observed and are theoretical only.

Or http://en.wikipedia.org/wiki/Ring_singularity" which are equally as interesting.

Cosmo Novice said:
I think black holes would appear to the observer as 2D circular void - it would not have any dimension other than 2D from FoR of the observer? It would just look like a completely black "hole" and if you could move around it at relatavistic speeds in any direction (outside of the EH) it would look as if the "hole" were rotating with you.

Indeed though you may still perceive it to be a sphere by virtue of orbiting it and always seeing a circle.

Cosmo Novice said:
This is assuming the BH has no large accretion discs, can anyone advise if the disc is a disc in the traditional sense or a 3D envelopment?

http://en.wikipedia.org/wiki/Accretion_disc" are 3d but they are disc shaped.
 
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Thank you everyone. Do we know enough about the physics of a black hole to accurately model it on a computer? If so, I would think the software would allow a user to rotate around it from all angles to see its full shape.
 
Astroboy123 said:
Thank you everyone. Do we know enough about the physics of a black hole to accurately model it on a computer? If so, I would think the software would allow a user to rotate around it from all angles to see its full shape.

Probably is such sofftware but as black holes should contain a singularity by their very nature and a singularity is mathematical nonsense and not considered a real singularity (an object with zero volume and infinite mass) but a point where current mathematics theory breaks down and general relativity no longer holds true - this is where a theory of quantum gravity is required.

Their shape is pretty much as described - a 2D looking spherical hole in 3d space that looks the same from all dimensions - unless surrounded by an accretian disc.
 
I would figure a sphere but slightly streched at the equatord due to the spin and all the other matter around the disc
 

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