Alternative of event horizon first suggested by Stephen Hawking
In general relativity, an apparent horizon is a surface that is the boundary between light rays that are directed outwards and moving outwards and those directed outward but moving inward.
Apparent horizons are not invariant properties of spacetime, and in particular, they are distinct from event horizons. 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.
The notion of a horizon in general relativity is subtle and depends on fine distinctions.
In general relativity, an apparenthorizon is a surface that is the boundary between light rays that are directed outwards and moving outwards and those...
referred to as elevation (el.) or apparent height, is the angle between the object and the observer's local horizon. For visible objects, it is an angle...
The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near...
Apparent magnitude (m) is a measure of the brightness of a star or other astronomical object to an observer on Earth. An object's apparent magnitude depends...
angle between the apparenthorizon as seen by an observer and the geometric (or sensible) horizon. This is known as the dip of the horizon and varies from...
absolute horizons and apparenthorizons; the notion of a horizon in general relativity is subtle, and depends on fine distinctions. An absolute horizon is only...
create an apparenthorizon (which in reality will not be horizontal) against an appropriate background, and the eye relies on the apparent relative height...
limb, rather than its center, appears to cross the horizon. The apparent radius of the Sun at the horizon is 16 arcminutes. These two angles combine to define...
is called an apparenthorizon. A related term trapped null surface is often used interchangeably. However, when discussing causal horizons, trapped null...
century. An apparent distance theory evidently was first clearly described by Cleomedes around 200 A.D. The theory proposes that the horizon Moon looks...
The British Post Office scandal, also called the Horizon IT scandal, involved Post Office Limited pursuing thousands of innocent subpostmasters for shortfalls...
geometrically below the horizon. Refraction also affects the apparent shape of the Sun when it is very close to the horizon. It makes things appear higher...
Moon on the eastern horizon at one moment sees it on the western horizon about 12 hours later. This adds an oscillation to the apparent progression of the...
Log Horizon (Japanese: ログ・ホライズン, Hepburn: Rogu Horaizun) is a Japanese novel series written by Mamare Touno and illustrated by Kazuhiro Hara. It began...
slightly greater than the apparent diameter of the Sun, so when the bottom of the sun's disc appears to touch the horizon, the sun's true altitude is...
theft, false accounting and fraud because of apparent shortfalls at their branches due to flaws in the Horizon accounting software used by the Post Office...
the apparent positions of stars slightly when they are close to the horizon and makes the sun visible before it geometrically rises above the horizon during...
"Equipartition of energy and the first law of thermodynamics at the apparenthorizon". International Journal of Modern Physics D. 20 (4): 553–559. arXiv:1001...
The Event Horizon Telescope (EHT) is a large telescope array consisting of a global network of radio telescopes. The EHT project combines data from several...
Sun always rises and sets vertically, following an apparent path nearly perpendicular to the horizon. Due to the axial tilt of Earth, Sun always lies within...
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