Light (or "light" in some languages) is electromagnetic radiation within a certain portion of the electromagnetic spectrum. Light is visible to the human eye and is responsible for the sense of sight. It is one of the fundamental forms of energy along with kinetic and potential energy. Light can be produced in a variety of ways, including combustion, friction, and the movement of charged particles including electrons. Light has a complicated relationship with other forms of energy, including sound, heat, and electricity. Light can move and travel faster than any other form of energy and is often used to carry information over long distances. Light has the ability to excite atoms, cause chemical reactions, and activate electrical circuits. Light can also be used to measure distance, intensity, and location of objects, and to study the movement of celestial bodies. It is used in medicine, manufacturing, engineering, and navigation. It plays an important role in astronomical studies, allowing scientists to study distant stars and galaxies. Light has long been an important source of energy and light sources, such as the sun, stars, fire, and lamps, have been fundamental to human development and advancement. The use of electric light became commonplace in the late 19th century, and has been used ever since. Light plays a key role in our daily lives, providing a means of communication, work, and leisure.