event horizon


Definition of event horizon 

: the surface of a black hole : the boundary of a black hole beyond which nothing can escape from within it

Examples of event horizon in a Sentence

Recent Examples on the Web

One of the main features of black holes is the event horizon, a region of space-time beyond which nothing can escape, not even light. Marcus Woo, Scientific American, "Gravitational “Echoes” Could Reveal Colliding Wormholes," 19 June 2018 But because any information that goes into a black hole is gone for good, an event horizon doesn’t jibe with quantum mechanics. Marcus Woo, Scientific American, "Gravitational “Echoes” Could Reveal Colliding Wormholes," 19 June 2018 Which means the guy not only knows about event horizons and gravitational lensing but stuff like tidal forces (what!), x-ray binaries (hey now!), and active galactic nuclei (oh my god!). Robbie Gonzalez, WIRED, "An Astronomer Explains Black Holes at 5 Levels of Difficulty," 5 July 2018 The gasses falling into the black hole experience high amounts of energy and glow brightly around the event horizon. David Grossman, Popular Mechanics, "The Fastest-Growing Black Hole Could Swallow the Sun in Two Days," 16 May 2018 At the event horizon, Hawking realized in 1974, one particle in a pair can fall into the black hole while the other escapes. Adrian Cho, Science | AAAS, "Hawking’s final quest: saving quantum theory from black holes," 20 Mar. 2018 The shoe-shop event horizon Lobb, and firms like it, make shoes using patterns called lasts. The Economist, "Shoemakers bring bespoke footwear to the high street," 22 May 2018 The black hole is demarcated by an event horizon, a point of no return: matter that falls in cannot get back out. George Musser, Scientific American, "What Is Spacetime?," 8 May 2018 That event horizon will likely be surrounded by an accretion disc, a bright, incredibly energetic ring of matter that swirls around the black hole. Brian Resnick, Vox, "Most images of black holes are illustrations. Here’s what our telescopes actually capture.," 6 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'event horizon.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of event horizon

1956, in the meaning defined above

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Last Updated

5 Oct 2018

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The first known use of event horizon was in 1956

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evasion of direct action or statement

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