Matches in DBpedia 2014 for { <http://dbpedia.org/resource/Penrose–Hawking_singularity_theorems> ?p ?o. }
Showing items 1 to 23 of
23
with 100 items per page.
- Penrose–Hawking_singularity_theorems abstract "The Penrose–Hawking singularity theorems are a set of results in general relativity which attempt to answer the question of when gravitation produces singularities.A singularity in solutions of the Einstein field equations is one of two things: a situation where matter is forced to be compressed to a point (a space-like singularity) a situation where certain light rays come from a region with infinite curvature (time-like singularity)Space-like singularities are a feature of non-rotating uncharged black-holes, while time-like singularities are those that occur in charged or rotating black hole exact solutions. Both of them have the following property:geodesic incompleteness: Some light-paths or particle-paths cannot be extended beyond a certain proper-time or affine-parameter (affine parameter is the null analog of proper time).It is still an open question whether time-like singularities ever occur in the interior of real charged or rotating black holes, or whether they are artifacts of high symmetry and turn into spacelike singularities when realistic perturbations are added.The Penrose theorem guarantees that some sort of geodesic incompleteness occurs inside any black hole, whenever matter satisfies reasonable energy conditions. (It does not hold for matter described by a super-field, i.e., the Dirac field) The energy condition required for the black-hole singularity theorem is weak: it says that light rays are always focused together by gravity, never drawn apart, and this holds whenever the energy of matter is non-negative.Hawking's singularity theorem is for the whole universe, and works backwards-in-time: in Hawking's original formulation, it guaranteed that the Big Bang has infinite density. Hawking later revised his position in A Brief History of Time (1988) where he stated that "there was in fact no singularity at the beginning of the universe" (p50). This revision followed from quantum mechanics, in which general relativity must break down at times less than the Planck time. Hence general relativity cannot be used to show a singularity.Penrose's theorem is more restricted, it only holds when matter obeys a stronger energy condition, called the dominant energy condition, which means that the energy is bigger than the pressure. All ordinary matter, with the exception of a vacuum expectation value of a scalar field, obeys this condition. During inflation, the universe violates the stronger dominant energy condition (but not the weak energy condition), and inflationary cosmologies avoid the initial big-bang singularity, rounding them out to a smooth beginning.".
- Penrose–Hawking_singularity_theorems wikiPageID "294408".
- Penrose–Hawking_singularity_theorems wikiPageRevisionID "599312536".
- Penrose–Hawking_singularity_theorems subject Category:General_relativity.
- Penrose–Hawking_singularity_theorems subject Category:Mathematical_methods_in_general_relativity.
- Penrose–Hawking_singularity_theorems subject Category:Physics_theorems.
- Penrose–Hawking_singularity_theorems subject Category:Theorems_in_general_relativity.
- Penrose–Hawking_singularity_theorems comment "The Penrose–Hawking singularity theorems are a set of results in general relativity which attempt to answer the question of when gravitation produces singularities.A singularity in solutions of the Einstein field equations is one of two things: a situation where matter is forced to be compressed to a point (a space-like singularity) a situation where certain light rays come from a region with infinite curvature (time-like singularity)Space-like singularities are a feature of non-rotating uncharged black-holes, while time-like singularities are those that occur in charged or rotating black hole exact solutions. ".
- Penrose–Hawking_singularity_theorems label "Penrose–Hawking singularity theorems".
- Penrose–Hawking_singularity_theorems label "Singularitäten-Theorem".
- Penrose–Hawking_singularity_theorems label "Teoremas de singularidade Penrose-Hawking".
- Penrose–Hawking_singularity_theorems label "Teoria osobliwości Penrose'a-Hawkinga".
- Penrose–Hawking_singularity_theorems label "Théorèmes sur les singularités".
- Penrose–Hawking_singularity_theorems label "特異点定理".
- Penrose–Hawking_singularity_theorems sameAs Penrose%E2%80%93Hawking_singularity_theorems.
- Penrose–Hawking_singularity_theorems sameAs Singularitäten-Theorem.
- Penrose–Hawking_singularity_theorems sameAs Théorèmes_sur_les_singularités.
- Penrose–Hawking_singularity_theorems sameAs 特異点定理.
- Penrose–Hawking_singularity_theorems sameAs Teoria_osobliwości_Penrose'a-Hawkinga.
- Penrose–Hawking_singularity_theorems sameAs Teoremas_de_singularidade_Penrose-Hawking.
- Penrose–Hawking_singularity_theorems sameAs Q1452678.
- Penrose–Hawking_singularity_theorems sameAs Q1452678.
- Penrose–Hawking_singularity_theorems wasDerivedFrom Penrose–Hawking_singularity_theorems?oldid=599312536.