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
Recent Examples on the Web
Additionally, this quasar is also producing jets of particles moving at nearly the speed of light, a rare feature among quasars.
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Rupendra Brahambhatt, Interesting Engineering, 21 Sep. 2025
Meanwhile, lasers travel at the speed of light, can engage with multiple targets, and are famous for their dollar-a-shot ammunition costs.
—New Atlas, 18 Sep. 2025
Cosmic winds produced at or around the Eddington limit can flow as fast as 124 million miles per hour and even up to about 30% the speed of light.
—Robert Lea, Space.com, 18 Sep. 2025
That’s more than 1 percent of the speed of light!
—Phil Plait, Scientific American, 11 Sep. 2025
See All Example Sentences for speed of light
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Rupendra Brahambhatt, Interesting Engineering, 21 Sep. 2025
Meanwhile, lasers travel at the speed of light, can engage with multiple targets, and are famous for their dollar-a-shot ammunition costs.
—New Atlas, 18 Sep. 2025
Cosmic winds produced at or around the Eddington limit can flow as fast as 124 million miles per hour and even up to about 30% the speed of light.
—Robert Lea, Space.com, 18 Sep. 2025
That’s more than 1 percent of the speed of light!
—Phil Plait, Scientific American, 11 Sep. 2025
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 24 Sep. 2025.
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