What is "event horizon"

event horizon \e*vent" ho*ri"zon\n. (Physics, Astron.) the boundary surface surrounding a black hole, from outside of which nothing inside can be observed, because nothing inside that surface, even light, can escape beyond it. See also black hole and escape velocity.

n. 1 (context astrophysics English) The gravitational sphere of a black hole within which the escape velocity is greater than the speed of light. 2 (context by extension English) A point of no return.

Event Horizon is the name of a large-scale public sculpture installation by the English artist Antony Gormley. In 2012, they were installed in downtown São Paulo and Rio de Janeiro, Brazil. Gormley describes his statues as "...showing solitary figures installed in groups yet retaining their sense of solitude and reflection."

Event horizon or Event Horizon may refer to:

• Event horizon, a boundary around a black hole inside which events can not affect an outside observer.
• Event Horizon (film), a 1997 science fiction/horror film
• Event Horizon (sculpture), a site installation by Antony Gormley
• Event Horizon, a story told in the Voyager Simulator at the Christa McAuliffe Space Education Center
• Event Horizon, a fictional company in the novels of the Greg Mandel trilogy by English science fiction writer Peter F. Hamilton.
• "Event Horizon", a 2006 track by Detroit techno moniker Arpanet
• Event Horizon, an 2012 album by metal band I Am I

Event Horizon is a 1997 British-American science fiction horror film. The screenplay was written by Philip Eisner, with an uncredited rewrite by Andrew Kevin Walker, and directed by Paul W. S. Anderson. The film stars Laurence Fishburne and Sam Neill.

Event Horizon received negative reviews upon release with most critics comparing the film to Alien, Hellraiser, The Black Hole, Solaris, Star Trek, and 2001: A Space Odyssey. The film was also a box office bomb, grossing $26.7 million against a $60 million production budget. In recent years though, in a similar fashion to Blade Runner and John Carpenter's The Thing, it has come to be regarded as a unique contribution to the sci-fi genre with positive contemporary reviews.

In general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. In layman's terms, it is defined as "the point of no return", i.e., the point at which the gravitational pull becomes so great as to make escape impossible, even for light. An event horizon is most commonly associated with black holes. Light emitted from inside the event horizon can never reach the outside observer. Likewise, any object approaching the horizon from the observer's side appears to slow down and never quite pass through the horizon, with its image becoming more and more redshifted as time elapses. The traveling object, however, experiences no strange effects and does, in fact, pass through the horizon in a finite amount of proper time. From here to the central singularity will take 0.0002 seconds in proper time, in free fall, for a 30 solar mass black hole. This infall time is proportional to the mass of the black hole.

More specific types of horizon include the related but distinct absolute and apparent horizons found around a black hole. Still other distinct notions include the Cauchy and Killing horizon; the photon spheres and ergospheres of the Kerr solution; particle and cosmological horizons relevant to cosmology; and isolated and dynamical horizons important in current black hole research.

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Event Horizon is the debut studio album by British heavy metal band I Am I, released in 2012. The album was originally released on USB, then onto CD format, making I Am I the first heavy metal band ever to release an album only on USB first. The album has a few traces of the power metal sound of ZP's previous band DragonForce. The album has been described as "old school meets new school" by lead vocalist and co-writer ZP Theart. The album is quite melodic and a bit similar to the AOR of the 1970s and 1980s. The lyrics deal with human emotions, social life, and issues that people struggle with.