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 Neutron stars are some of the densest objects in the universe, with intense gravitational fields—but not as intense as black holes, whose gravity is so strong that not even light can escape their event horizons. Isaac Schultz / Gizmodo, Quartz, 7 Apr. 2024 White holes also have a singularity, but their event horizons act differently. Paul M. Sutter, Discover Magazine, 26 July 2023 Only within a spherical boundary surrounding the black hole known as the event horizon would a person or object get pulled inexorably inward. Adam Mann, Scientific American, 14 Feb. 2023 My personal theory is that 1994 represents the event horizon. Rory Smith, New York Times, 22 Dec. 2023 The group has now developed a more sophisticated theory of gravity that can handle the region just inside the event horizon and doesn’t violate any current experimental data. Quanta Magazine, 21 Dec. 2023 Hair on the Horizon The idea that event horizons gather information and cause decoherence isn’t new. Thomas Lewton, Quanta Magazine, 7 Mar. 2023 They are surrounded by a boundary called the event horizon. Paul M. Sutter, Discover Magazine, 26 July 2023 Under the classical theory, an accreditation disk rotates in sync with a black hole and gradually falls below its event horizon, the point beyond which no light can escape. Matt Hrodey, Discover Magazine, 25 Sep. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'event horizon.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1956, in the meaning defined above

Time Traveler
The first known use of event horizon was in 1956

Dictionary Entries Near event horizon

Cite this Entry

“Event horizon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/event%20horizon. Accessed 24 Apr. 2024.

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