The theoretical description of light as electromagnetic waves has had an enormous impact on physics in the past two centuries. It was the first example of unification, i.e. the notion that electric and magnetic phenomena have a common origin. Besides, it led to the discovery of a new relativity principle called special relativity, and it disproved the existence of aether as a medium that was supposed to carry light as an elastic excitation. Perhaps the detection of gravitational wave will further confirm our fundamental ideas of space, time and mass.
Wave phenomena can be found everywhere in nature and the waves as described by classical mechanics are part of our daily experience. A wave is a propagating excitation of a medium – for example a mass of air or water – with the property that the medium counteracts the excitation: this counteraction is in fact the very reason for the propagation of waves.
View original post 1,174 more words