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Q & A: Speed of light

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Most recent answer: 02/22/2008
Is the speed of light in a vacuum is infinity speed? And if it is, then does this mean that time has slowed to stop?
- John (age 9)
The speed of light in vacuum is not infinite, it's c = 3x108 meters per second. That's fast but not infinite.  As an example, light will travel 30 centimeters (about 1 foot) in one billionth of a second.   Light going through a transparent medium like glass or water is slower.  V = c/n where V is the speed in the medium and n is the index of refraction of the material.


(published on 02/22/2008)

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