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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. Ergosphere - Wikipedia

    en.wikipedia.org/wiki/Ergosphere

    An implication of this dragging of space is the existence of negative energies within the ergosphere. Since the ergosphere is outside the event horizon, it is still possible for objects that enter that region with sufficient velocity to escape from the gravitational pull of the black hole.

  4. Trapped surface - Wikipedia

    en.wikipedia.org/wiki/Trapped_surface

    Closed trapped surfaces are a concept used in black hole solutions of general relativity [1] which describe the inner region of an event horizon. Roger Penrose defined the notion of closed trapped surfaces in 1965. [2] A trapped surface is one where light is not moving away from the black hole.

  5. Black hole - Wikipedia

    en.wikipedia.org/wiki/Black_hole

    The term "black hole" was used in print by Life and Science News magazines in 1963, [61] and by science journalist Ann Ewing in her article " 'Black Holes' in Space", dated 18 January 1964, which was a report on a meeting of the American Association for the Advancement of Science held in Cleveland, Ohio. [62] [63]

  6. Malament–Hogarth spacetime - Wikipedia

    en.wikipedia.org/wiki/Malament–Hogarth_spacetime

    This effect is even more pronounced near the inner horizon due to the extreme curvature of spacetime in this region. The energy of the infalling radiation increases as it approaches the inner horizon because of this blueshifting. The energy appears to become infinite from the perspective of an observer falling into the black hole.

  7. 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 ...

  8. Kerr metric - Wikipedia

    en.wikipedia.org/wiki/Kerr_metric

    The Kerr metric or Kerr geometry describes the geometry of empty spacetime around a rotating uncharged axially symmetric black hole with a quasispherical event horizon.The Kerr metric is an exact solution of the Einstein field equations of general relativity; these equations are highly non-linear, which makes exact solutions very difficult to find.

  9. 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.