Answers to Beginner Questions about Black Hole Event Horizons

In summary: All conceptual drawings I have seen leave out one or more components.Yes, it is possible to fit all the components of a black hole theory into a single detailed drawing. However, doing so would require a very high level of mathematical sophistication and understanding of the relevant physical concepts.
  • #1
K. Doc Holiday
32
13
I have searched the threads. Got some great insight but didn't find the answers to some of my questions

Questions about Event Horizons

Most of the textbooks and papers I have read no longer picture or talk about Einstein's original concept of a black hole; the Einstein - Rosen bridge. First question: is this universal?

Many texts say the event horizon is a sphere. Is this universally accepted? Or does it only apply to non rotating black holes?

Does an EH sphere eliminate the need for an accretion disk since matter can flow into a sphere from every angle?

Are black holes still considered "infinite singularities"? I ask because a sphere is finite with a measurable volume.

Does a 3 billion solar mass black hole like M87 have a greater volume than a 10 solar mass black hole?

Which sides of the sphere do the relativistic jets shoot out of?

If it isn't a sphere then where are the jets in relation to the accretion discs? Do the jets disrupt the disc?

All conceptual drawings I have seen leave out one or more components. Is it possible to fit all the components of a black hole theory into a single detailed drawing?

Thanks ahead of time for your patience.
Doc
 
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  • #2
K. Doc Holiday said:
Does an EH sphere eliminate the need for an accretion disk since matter can flow into a sphere from every angle?
There is no "need" for an accretion disc.
However, event horizon is small. If the infalling matter were in small amounts, most infalling particles would not fall in the black hole because they would pass the vicinity of black hole on hyperbolic or relativistic open orbits - only matter very directly falling towards the hole would enter the event horizon.
If larger amounts of matter fall in, particles near the black hole on a flyby may collide with other particles flying by black hole in different directions, be slowed down by such collision and caught into orbit around the hole.
Now, if there is some direction/half-plane in which slightly more matter happens to fall in than from other direction, the matter falling in from that direction would concentrate in an accretion disc. The matter falling in from other directions would be slowed down by colliding with accretion disc and would fall in the hole - only (some of the) matter in the disc would be left over orbiting.
 
  • #3
The particles that comprise black hole jets are believed to originate from their accretion disc. The jets themselves emanate from the magnetic poles of a black hole where the magnetic field is weak enough to allow sufficiently energetic particles to escape - much like Earth's auroras originate from the magnetic poles of earth. The magnetic poles of Earth and black holes are aligned with their spin axis. See http://www.sciencemag.org/news/2014/11/what-powers-black-holes-mighty-jets for discussion
 
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1. What is an event horizon?

An event horizon is a boundary in space around a black hole, beyond which the gravitational pull is so strong that nothing, not even light, can escape.

2. How is an event horizon formed?

An event horizon is formed when a massive star collapses and its gravity becomes so strong that it traps all matter and energy within its boundaries.

3. Can anything pass through an event horizon?

No, once an object crosses the event horizon, it is pulled into the black hole and cannot escape.

4. Is an event horizon visible?

No, an event horizon cannot be seen as it is a boundary in space. However, scientists can detect its presence through the effects it has on surrounding matter and light.

5. Can event horizons be found in places other than black holes?

Yes, event horizons can also be found in other cosmological objects such as white holes and wormholes, but they have not been scientifically proven to exist yet.

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