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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 ...
The ergosphere of a black hole is a volume bounded by the black hole's event horizon and the ergosurface, which coincides with the event horizon at the poles but is at a much greater distance around the equator.
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.
(Supermassive black holes up to 21 billion (2.1 × 10 10) M ☉ have been detected, such as NGC 4889.) [16] Unlike stellar mass black holes, supermassive black holes have comparatively low average densities. (Note that a (non-rotating) black hole is a spherical region in space that surrounds the singularity at its center; it is not the ...
The first image (silhouette or shadow) of a black hole, taken of the supermassive black hole in M87 with the Event Horizon Telescope, released in April 2019. The black hole information paradox [1] is a paradox that appears when the predictions of quantum mechanics and general relativity are combined.
Extremal black hole – black hole with the minimal possible mass that can be compatible with a given charge and angular momentum. Black hole electron – if there were a black hole with the same mass and charge as an electron, it would share many of the properties of the electron including the magnetic moment and Compton wavelength.
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.
The black hole event horizon bordering exterior region I would coincide with a Schwarzschild t-coordinate of + while the white hole event horizon bordering this region would coincide with a Schwarzschild t-coordinate of , reflecting the fact that in Schwarzschild coordinates an infalling particle takes an infinite coordinate time to reach the ...