speed of light
noun phrase
: a fundamental physical constant that is the speed at which electromagnetic radiation propagates in a vacuum and that has a value fixed by international convention of 299,792,458 meters per second
—symbol c
Examples of speed of light in a Sentence
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The results reveal jets carrying energy equal to around 10,000 suns while moving at nearly half the speed of light, offering one of the clearest views yet of how black holes pump energy back into the universe.
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Rupendra Brahambhatt, Interesting Engineering, 10 May 2026
Scientists have not, however, been able to converge on a measurement with a level of precision comparable to that of constants such as the speed of light (299,792,458 meters per second) or Planck’s constant, which is known to eight decimal places.
—Katie Hunt, CNN Money, 7 May 2026
There’s no way that an object, any object, can move through space at speeds that exceed the speed of light.
—Big Think, 1 May 2026
Polaritons move relatively sluggishly—around 100 times slower than the speed of light.
—Adam Kovac, Scientific American, 30 Apr. 2026
See All Example Sentences for speed of light
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Rupendra Brahambhatt, Interesting Engineering, 10 May 2026
Scientists have not, however, been able to converge on a measurement with a level of precision comparable to that of constants such as the speed of light (299,792,458 meters per second) or Planck’s constant, which is known to eight decimal places.
—Katie Hunt, CNN Money, 7 May 2026
There’s no way that an object, any object, can move through space at speeds that exceed the speed of light.
—Big Think, 1 May 2026
Polaritons move relatively sluggishly—around 100 times slower than the speed of light.
—Adam Kovac, Scientific American, 30 Apr. 2026
See All Example Sentences for speed of light
Cite this Entry
“Speed of light.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/speed%20of%20light. Accessed 16 May. 2026.
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