Naked singularity
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In general relativity, a naked singularity is a gravitational singularity without an event horizon. The singularities inside black holes are always surrounded by an area which does not allow light to escape, and therefore cannot be directly observed. A naked singularity, by contrast, is a point in space where the density is infinite and which is observable from the outside.
The theoretical existence of naked singularities is important because their existence would mean that it would be possible to observe the collapse of an object to infinite density.
Computer simulations of the collapse of a disk of dust have indicated that these objects can exist, and thus the cosmic censorship hypothesis (stating that singularities are always hidden) does not hold. Stephen Hawking famously lost a bet about this question. [1]
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[edit] Predicted formation
From concepts drawn of rotating black holes, it is shown that a singularity, spinning rapidly, can become a ring-shaped object. This results in two event horizons, as well as an ergosphere, which draw closer together as the spin of the singularity increases. When the outer and inner event horizons merge, they shrink toward the rotating singularity and eventually expose it to the rest of the universe.
A singularity rotating so fast could be created by the collapse of dust or by a supernova of a fast-spinning star. Studies of pulsars and the usage of computer simulations have shown that a collapsing star could make a structure spinning fast enough to become such a naked singularity.
This is, of course, an example of a mathematical difficulty (divergence to infinity of the density) which reveals a more profound problem in our understanding of the relevant physics involved in the process. A workable theory of quantum gravity should be able to solve problems such as this.
[edit] Effects
A naked singularity could allow scientists to observe an infinitely dense material, which would under normal circumstances be impossible by the cosmic censorship hypothesis. A singularity, without a theory of quantum gravity, would break down the laws of physics and supposedly cause chaos among the cosmos if unshielded by an event horizon. In addition, without an event horizon of any kind, some predict that naked singularities would actually emit light, rather than consume it voraciously as normal black holes do.
If a naked singularity occurred, any random event of the cosmos may, theoretically, be possible, and normally impossible occurrences may be triggered, ultimately altering what we now know as the laws of physics altogether.
Because no such objects have been found in the universe, and no such effects have been observed, many scientists are convinced that a theory of quantum gravity that coincides with electromagnetism would disallow such objects to come into being.
[edit] See also
- List of astronomical topics
- List of physics topics
- Singularities in relativity
