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
However, general relativity also predicts that when objects accelerate in spacetime, this generates ripples that radiate outward at the speed of light.
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Robert Lea, Space.com, 2 Mar. 2026
But signals don’t go from the generating source to the observer instantaneously; all physical signals propagate at a finite speed, with the fastest possible speed being the speed of light in a vacuum, c, or 299,792,458 m/s.
—Big Think, 25 Feb. 2026
For the launch colorway, a vivid graphic may initially bring to mind heat maps with its application of blue, green, yellow and red — but the choice was actually made to invoke a temporal fold, a theoretical concept of bending spacetime to move faster than the speed of light.
—Ian Servantes, Footwear News, 13 Feb. 2026
That conversion is governed by Einstein’s most famous equation, E = mc2, where m is the mass of the black holes lost to energy and c is the speed of light.
—Phil Plait, Scientific American, 13 Feb. 2026
See All Example Sentences for speed of light
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Robert Lea, Space.com, 2 Mar. 2026
But signals don’t go from the generating source to the observer instantaneously; all physical signals propagate at a finite speed, with the fastest possible speed being the speed of light in a vacuum, c, or 299,792,458 m/s.
—Big Think, 25 Feb. 2026
For the launch colorway, a vivid graphic may initially bring to mind heat maps with its application of blue, green, yellow and red — but the choice was actually made to invoke a temporal fold, a theoretical concept of bending spacetime to move faster than the speed of light.
—Ian Servantes, Footwear News, 13 Feb. 2026
That conversion is governed by Einstein’s most famous equation, E = mc2, where m is the mass of the black holes lost to energy and c is the speed of light.
—Phil Plait, Scientific American, 13 Feb. 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 12 Mar. 2026.
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