The speed of light in vacuum, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately...

Faster-than-light (superluminal or supercausal) travel and communication are the conjectural propagation of matter or information faster than the speed of light (c)...

speed of light in Wiktionary, the free dictionary. The speed of light is a physical constant, the rate at which light travels in a vacuum. Speed of Light...

"the speed of light" it is sometimes necessary to make the distinction between its one-way speed and its two-way speed. The "one-way" speed of light, from...

also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization. Its speed in vacuum...

A variable speed of light (VSL) is a feature of a family of hypotheses stating that the speed of light may in some way not be constant, for example, that...

Rømer's determination of the speed of light was the demonstration in 1676 that light has an apprehensible, measurable speed and so does not travel instantaneously...

differential measurement of the speed of light in water versus its speed in air. In 1862, he used a similar apparatus to measure the speed of light in the air. In...

The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in vacuum c = 299792458...

used a toothed wheel apparatus to perform an absolute measurement of the speed of light in air. Subsequent experiments performed by Marie Alfred Cornu in...