speed of light

physics
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Share
Share to social media
URL
https://mainten.top/science/speed-of-light
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

Also known as: c, electromagnetic constant, velocity of light

speed of light, speed at which light waves propagate through different materials. In particular, the value for the speed of light in a vacuum is now defined as exactly 299,792,458 metres per second.

The speed of light is considered a fundamental constant of nature. Its significance is far broader than its role in describing a property of electromagnetic waves. It serves as the single limiting velocity in the universe, being an upper bound to the propagation speed of signals and to the speeds of all material particles. In the famous relativity equation, E = mc2, the speed of light (c) serves as a constant of proportionality, linking the formerly disparate concepts of mass (m) and energy (E).

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Adam Augustyn.