Speed of light
speed-of-light-1753219826380-68b6fe
Description
The speed of light in vacuum, commonly denoted c, is a universal physical constant exactly equal to 299,792,458 metres per second. It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time interval of 1⁄299792458 second. The speed of light is the same for all observers, no matter their relative velocity. It is the upper limit for the speed at which information, matter, or energy can travel through space.
ID: speed-of-light-1753219826380-68b6fe
