time dilation


: a slowing of time in accordance with the theory of relativity that occurs in a system in motion relative to an outside observer and that becomes apparent especially as the speed of the system approaches that of light

called also time dilatation

Examples of time dilation in a Sentence

Recent Examples on the Web Researchers have confirmed that the effects of time dilation are present in the very early universe. Jackie Appel, Popular Mechanics, 6 July 2023 This slowing down of time due to travel, which is known as time dilation, has been verified through multiple experiments. Kat Friedrich, Popular Mechanics, 25 July 2023 The confirmation of time dilation back to the Cosmic Dawn brings with it another confirmation—one of Einstein’s Theory of Relativity. Jackie Appel, Popular Mechanics, 6 July 2023 To illustrate the effect of time dilation, Einstein proposed an example—the twin paradox—that is arguably the most famous thought experiment in relativity theory. Ronald C. Lasky, Scientific American, 24 Oct. 2014 Optical lattice clocks have been used at the University of Wisconsin–Madison and at the University of Colorado Boulder to measure this gravitational time dilation on sub-centimeter scales. Paul Lipman, Forbes, 27 Mar. 2023 The experimental strategies of the first section (the light-bulb flashes, the time dilation) that paradoxically made G and B’s relationship so believable all disappear, and the last section of the play becomes a long, naturalistically depicted conversation. Helen Shaw, Vulture, 21 Sep. 2021 This bending of space-time avoids the perils of time dilation. Kyle Hill, Discover Magazine, 31 May 2013 However, each four-minute trip equals four years on their space colony due to the effects of time dilation. Ariana Garcia, Chron, 17 June 2022 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'time dilation.' 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

1934, in the meaning defined above

Time Traveler
The first known use of time dilation was in 1934

Dictionary Entries Near time dilation

Cite this Entry

“Time dilation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/time%20dilation. Accessed 28 Feb. 2024.

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