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  2. Event horizon - Wikipedia

    en.wikipedia.org/wiki/Event_horizon

    In 1958, David Finkelstein used general relativity to introduce a stricter definition of a local black hole event horizon as a boundary beyond which events of any kind cannot affect an outside observer, leading to information and firewall paradoxes, encouraging the re-examination of the concept of local event horizons and the notion of black ...

  3. Dynamical horizon - Wikipedia

    en.wikipedia.org/wiki/Dynamical_horizon

    In theoretical physics, a dynamical horizon (DH) is a local description (i.e. independent of the global structure of space–time) of evolving black-hole horizons.In the literature there exist two different mathematical formulations of DHs—the 2+2 formulation developed first by Sean Hayward and the 3+1 formulation developed by Abhay Ashtekar and others (see Ashtekar & Krishnan 2004). [1]

  4. Apparent horizon - Wikipedia

    en.wikipedia.org/wiki/Apparent_horizon

    Within an apparent horizon, light does not move outward; this is in contrast with the event horizon. In a dynamical spacetime, there can be outgoing light rays exterior to an apparent horizon (but still interior to the event horizon). An apparent horizon is a local notion of the boundary of a black hole, whereas an event horizon is a global notion.

  5. Kruskal–Szekeres coordinates - Wikipedia

    en.wikipedia.org/wiki/Kruskal–Szekeres_coordinates

    The event horizons bounding the black hole and white hole interior regions are also a pair of straight lines at 45 degrees, reflecting the fact that a light ray emitted at the horizon in a radial direction (aimed outward in the case of the black hole, inward in the case of the white hole) would remain on the horizon forever. Thus the two black ...

  6. Reissner–Nordström metric - Wikipedia

    en.wikipedia.org/wiki/Reissner–Nordström_metric

    Although charged black holes with r Q ≪ r s are similar to the Schwarzschild black hole, they have two horizons: the event horizon and an internal Cauchy horizon. [8] As with the Schwarzschild metric, the event horizons for the spacetime are located where the metric component diverges; that is, where + = =

  7. Isolated horizon - Wikipedia

    en.wikipedia.org/wiki/Isolated_horizon

    The local nature of the definition of an isolated horizon makes it more convenient for numerical studies. The local nature makes the Hamiltonian description viable. This framework offers a natural point of departure for non-perturbative quantization and derivation of black hole entropy from microscopic degrees of freedom. [11]

  8. Outline of black holes - Wikipedia

    en.wikipedia.org/wiki/Outline_of_black_holes

    Jacob Bekenstein - for the foundation of black hole thermodynamics and the elucidation of the relation between entropy and the area of a black hole's event horizon. Karl Schwarzschild - found a solution to the equations of general relativity that characterizes a black hole.

  9. De Sitter–Schwarzschild metric - Wikipedia

    en.wikipedia.org/wiki/De_Sitter–Schwarzschild...

    It has two horizons, the cosmological de Sitter horizon and a Schwarzschild black hole horizon. For small mass black holes, the two are very different — there is a singularity at the center of the black hole, and there is no singularity past the cosmological horizon. But the Nariai limit considers making the black hole bigger and bigger ...