speed of light (in vacuum)

What is speed of light (in vacuum)?

speed of light (in vacuum) definition and meaning on Science terms:
The speed at which electromagnetic radiation propagates in a vacuum; it is defined as 299 792 458 m/s (186,282 miles/second). Einstein’s Theory of Relativity implies that nothing can go faster than the speed of light.


reference: https://imagine.gsfc.nasa.gov/resources/dictionary.html