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naked singularity

In general relativity, singularities – environs of infinite curvature – that form in the collapse of massive bodies or in similar processes are typically hidden inside black holes, in other words: spacetime in their vicinity is distorted so much that no information about the singularity can ever reach the outside world. Hypothetical singularities which are not cloaked in this way, and thus are visible to the rest of the cosmos, are called “naked”. By the cosmic censorship hypothesis, no realistic kind of collapse can lead to the formation of a naked singularity.

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singularity

Irregular boundary of spacetime in general relativity - region where spacetime simply comes to an end. Often, such boundaries are associated with spacetime curvature growing beyond all bounds and becoming infinitely large - so-called curvature singularities (notably Ricci singularities or Weyl singularities - but there are exceptions (for instance a conic singularities). According to general relativity, a singularity exists inside every black hole, and the starting point of any universe described by a big bang model is a singularity as well. The occurrence of singularities is a failure of general relativity - and a strong indication that the theory is incomplete. Instead, one could describe the earliest universe and the interior of black holes using a theory of quantum gravity. More information about singularities can be found in the spotlight texts Spacetime singularities and Of singularities and breadmaking.

naked singularity

In general relativity, singularities - environs of infinite curvature - that form in the collapse of massive bodies or in similar processes are typically hidden inside black holes, in other words: spacetime in their vicinity is distorted so much that no information about the singularity can ever reach the outside world. Hypothetical singularities which are not cloaked in this way, and thus are visible to the rest of the cosmos, are called "naked". By the cosmic censorship hypothesis, no realistic kind of collapse can lead to the formation of a naked singularity.

lead

Chemical element with the symbol Pb; each lead nucleus contains 82 protons. Lead nuclei, stripped of their electrons, are among the types of heavy ions which are brought into collision in particle accelerators such as the Relativistic Heavy Ion Collider in order to recreate the state of matter in the early universe shortly after the big bang.

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naked singularity

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