# Speed of light

###### About the speed of light
• The speed of light, 299,792,458 meters per second, is the maximum speed at which information can be transmitted through space.
• The fact that the speed of light is invariant for all observers, regardless of their relative motion, has important implications for our understanding of the behaviour of matter and energy in the universe.
• The first consequence of E=mc² is that if the speed of light (c) never changes then it is also true that m=E/c² so matter and energy are not distinct and separate entities but are instead different manifestations of the same underlying substance.
• The fact that the speed of light is invariant forms a key part of Einstein’s theory of relativity, which describes how the behaviour of space, time, and matter are interrelated.
• The invariance of the speed of light means that the relationship between mass and energy, as described by Einstein’s famous equation E=mc², is a universal relationship that holds true for all observers, regardless of their relative motion.
• The fact that the speed of light is invariant also forms a key part of Einstein’s theory of relativity, which describes how the behaviour of space, time, and matter are interrelated.
• The square of the speed of light (c2) appears in the equation because it relates the energy of an object to its mass and shows that a small amount of mass can be converted into a large amount of energy, and vice versa.
• If the speed of light were different, then the (c2) factor in the equation would be different as well. So the value of (c2) in the equation is a consequence of the nature of energy and mass, and the fact that the speed of light is a fundamental constant in the universe.
• The square of the speed of light (c2) serves as a conversion factor that relates the mass of an object to its energy content and shows the enormous amount of energy that can be released when a small amount of mass is converted into energy, as in nuclear reactions.
• The speed of light multiplied by itself = 299,792,458^2 = 89,875,517,873,681,764