Naked singularities, and Hawking

In summary, according to Greene, a naked singularity can theoretically be created in a black hole by continuously injecting high-magnitude angular momentum objects, but this process is unlikely to ever occur in practice.
  • #1
JustinLevy
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I've read that Hawking believes the Universe somehow prevents naked singularities, and made a bet about it with Kip Thorne.

But it seems to me that if you take a static black hole and continually inject material into it with high angular momentum, eventually you would have a naked singularity (since you'd eventually get an extremal black hole). This seems very general to me. Actually, since the momentum of a particle is unbounded, technically you should be able to do this with just a single particle, correct?

Clearly the answer can't be that simple.
What am I missing?
 
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  • #2
JustinLevy said:
I've read that Hawking believes the Universe somehow prevents naked singularities, and made a bet about it with Kip Thorne.

No. Hawking's bet with Thorne (and John Preskill) was concerned with the idea of information loss in black holes.

The idea that the universe prevents the formation of naked singularities refers to any of the various forms of the cosmic censorship conjecture, possibly the single most important unproven conjecture in mathematical relativity.
 
  • #3
JustinLevy said:
But it seems to me that if you take a static black hole and continually inject material into it with high angular momentum, eventually you would have a naked singularity (since you'd eventually get an extremal black hole). This seems very general to me. Actually, since the momentum of a particle is unbounded, technically you should be able to do this with just a single particle, correct?

I think there are some general arguments that you can spin a black hole up to a = M in principle, but not beyond. As matter is injected into the black hole to increase a, M also increases, and the maximum value for a/M is 1. Thorne showed that, in practice, a black hole can be spun up to only a = 0.998M.
shoehorn said:
No. Hawking's bet with Thorne (and John Preskill) was concerned with the idea of information loss in black holes.

Hawking also bet Preskill about the existence of naked singularities; see

http://www.theory.caltech.edu/~preskill/bets.html.
 
  • #5
In THE ELEGANT UNIVERSE (1999) Brian Greene in chapter 13, Black Holes: A string/M theory Perspective, has a great discussion on naked/hidden singularities and how Calabi Yau shapes, perhaps the fundamental description of additional dimensions in our universe, can shield us from them. It turns out there are many ways space tearing transitions can occur, many ways Calabi Yau shapes can continuously transform, and how certain physical configurations appear as either black holes or elementary particles...yes, it appears a massive black hole can transition to a massles particle following a three dimensional sphere collapse to a pinched point...corresponding to a black hole!

Wikipedia at http://en.wikipedia.org/wiki/Conifold_transition has a brief mathematical discussion. In the discussion here, "smooth transitions" I believe means "continuous" shielding/hiding underlying singularities. As usual while Wikipedia may be technically correct, it's descriptions are all too often rather opaque without other sources.
 

FAQ: Naked singularities, and Hawking

1. What is a naked singularity?

A naked singularity is a hypothetical point in space where the curvature of spacetime becomes infinite, but it is not hidden behind an event horizon like a black hole. This means that the singularity can be observed from the outside, unlike a black hole where everything is trapped inside the event horizon.

2. What is the difference between a naked singularity and a black hole?

The main difference between a naked singularity and a black hole is the presence of an event horizon. In a black hole, the event horizon acts as a point of no return where the escape velocity exceeds the speed of light. In a naked singularity, there is no event horizon, so objects can theoretically escape from the singularity's gravitational pull.

3. Are naked singularities real or just theoretical?

Currently, naked singularities are considered to be purely theoretical as there is no observational evidence to support their existence. However, some theories and mathematical models suggest that they could potentially exist in certain circumstances.

4. How do naked singularities relate to Hawking radiation?

Naked singularities and Hawking radiation are both concepts related to black holes. Hawking radiation is a process by which black holes emit radiation and eventually evaporate. Some theories suggest that naked singularities could also exhibit this behavior, leading to the possibility of observing them indirectly through the detection of Hawking radiation.

5. What are the implications of naked singularities for our understanding of the universe?

If naked singularities do exist, they could challenge our current understanding of the laws of physics and the nature of space and time. They could also have important implications for the study of black holes and the behavior of matter at extreme densities. However, until there is solid evidence for their existence, their impact on our understanding of the universe remains uncertain.

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