Are Black Holes Truly 3D Phenomena?

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Discussion Overview

The discussion revolves around the dimensionality of black holes, specifically whether they are truly three-dimensional phenomena or can be represented in simpler models. Participants explore various models and analogies related to black holes, including the event horizon and gravitational effects, while considering implications for how objects interact with black holes.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that a black hole must be a three-dimensional phenomenon, questioning the validity of two-dimensional models like the whirlpool analogy.
  • Others argue that the event horizon is indeed three-dimensional and that the two-dimensional whirlpool depiction is inaccurate.
  • A participant questions how gravity operates in three dimensions and whether mass influences this behavior, expressing uncertainty about how objects can orbit a black hole without being drawn in from all directions.
  • One participant explains that gravity from a black hole functions similarly to that of the Sun, stating that black holes do not "suck in" objects but exert gravitational force that increases as one approaches.
  • Another participant suggests that black holes represent stable systems rather than constantly consuming everything around them, using a metaphor to illustrate this idea.

Areas of Agreement / Disagreement

Participants express differing views on the nature of black holes, particularly regarding their dimensionality and behavior. While some agree on the three-dimensional nature of the event horizon, others challenge the implications of this understanding, leading to unresolved questions about gravitational interactions.

Contextual Notes

Participants rely on various models and analogies, which may depend on specific definitions and assumptions about gravity and black holes. There are unresolved aspects regarding the behavior of objects near black holes and the implications of gravitational forces in three dimensions.

Bujon
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So having considered the classical depiction of a black hole resembling a whirlpool, my thought process is that a black hole must be a 3-d phenomenon. Therefore I can not see how a event horizon/swirlpool model could be plausible unless the centre of a black hole was spinning and literally was only attracting matter on a 2-d plane. Is it possible a black is more like a bubble in the bath water, an empty vacuum which doesn't actually have an even horizon as such, perhaps magnetic in nature in the 3-d. Be interested to hear your thoughts.
 
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The event horizon of a black hole is 3d, not 2d. The 2d whirlpool depiction is completely inaccurate. It is not magnetic in nature, but gravitational.
 
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Can gravity pull from a centre point equally 3dimensionally? And is that just down to the mass? If that was the case then whatever your approach to a black hole would mean you were going to be sucked toward it, and the event horizon would be your point of no return, which I can grasp. Just not sure how something could orbit a black hole without seeing stuff from above and below and beyond that black hole on every point on the x and y and z axis being sucked in.
 
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Bujon said:
Can gravity pull from a centre point equally 3dimensionally?

Of course! That's exactly how it works. Take for example the Earth. Every single point-like portion of the Earth exerts a gravitational force on all objects in all directions, with the force being inversely proportional to r2, where r is the distance between the object and that portion of the Earth. The total gravitational force exerted by the Earth on an object is just the sum of the force exerted by all of these portions.

Bujon said:
If that was the case then whatever your approach to a black hole would mean you were going to be sucked toward it

Contrary to what you've heard or read, black holes do not "suck in objects". Gravity from a black hole works just like the gravity from the Sun. The planets are not being sucked into the Sun, are they? Gravity from a 1-solar mass black hole would be identical to gravity from the Sun until you were closer than one solar radii to the black hole, at which point the gravitational force is simply larger than that of the Sun, increasing further as you get closer to the black hole. Objects still do not get sucked in.
 
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Ok well explained, so a black hole in that case represents a stable system. They are not necessarily 'growing' eating up everything in sight, but more have finished the main course and are now sat bulging on the sofa so to speak.
 
You could think of it that way, sure.
 

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