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 According to the equations of relativity, information that travels past the event horizon into a black hole is forever lost—erased, as far as any outside observer is concerned. James Gleick, The New York Review of Books, 13 Apr. 2021 In the region of the event horizon, fluctuations in the vacuum would lead to a stream of particles away from the black hole. James Gleick, The New York Review of Books, 13 Apr. 2021 The telescope is named after the point of no return around a black hole; beyond the event horizon, all light and matter is consumed. New York Times, 24 Mar. 2021 The event horizon is defined as the boundary marking the limits of a black hole, which means nothing can cross that threshold and then escape it -- including light. Ashley Strickland, CNN, 24 Mar. 2021 Now, a second special case could do kind of the same thing, but from the opposite end: Black holes that spin fast enough end up creating a kind of vortex of hairs that link it across the event horizon as well. Caroline Delbert, Popular Mechanics, 14 Dec. 2020 The bad news is that the event horizon marks the edge of the abyss. Chris Impey, The Conversation, 30 Oct. 2020 Recently, scientists released new observations about aging black holes, a special case in which the black holes appear to slacken and begin belching information back over the event horizon. Caroline Delbert, Popular Mechanics, 14 Dec. 2020 This conjecture asserts that all singularities are hidden behind an event horizon so that matter approaching them has no causal effect on what happens outside the horizon. Avi Loeb, Scientific American, 7 Nov. 2020

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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Time Traveler for event horizon

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The first known use of event horizon was in 1956

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Statistics for event horizon

Last Updated

2 May 2021

Cite this Entry

“Event horizon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/event%20horizon. Accessed 23 Jun. 2021.

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