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 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.
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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 might be created by the collapse of dust or by a supernova of a fast-spinning star. Studies of pulsars[citation needed] and some computer simulations (1997 by Matthew Choptuik, University of Texas at Austin, for which he was awarded the Xanthopoulos Award in Gravitation and Cosmology by the International Society for General Relativity and Gravitation) have happened.
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 these.
[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. Without an event horizon of any kind, some speculate that naked singularities could actually emit light. [1]
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 the Standard Model would disallow such objects to come into being.
[edit] In Fiction
- A naked singularity almost appears in the six episode OAV series Diebuster. In the final episode, a black hole's event horizon is somehow breached when struck by a powerful force. It is stated that this 'crack' would eventually lead to the singularity inside being exposed to the universe. In the same scene, one character speculates that the Big Bang was the aftermath of such an event.
[edit] See also
[edit] References
- ^ Is a 'naked singularity' lurking in our galaxy?. New Scientist. Retrieved on 2008-03-06.
