The Restless universe
|Introduction to The restless Universe|
1 The lawful Universe2 The clockwork Universe
5 The uncertain Universe
Other titles in the Physical World series
Answer and comments
Faraday introduced fields in the context of magnetism and electricity, and Maxwell established the reality of these fields by showing that wave-like disturbances of electric and magnetic fields can travel through space at the speed of light. He interpreted light as an electromagnetic wave and predicted the existence of longer wavelength electromagnetic waves (radio waves). Einstein's general theory of relativity is a field theory of gravitation in which the field describes the curvature of space-time.
A quantum theory of fields was developed which incorporates ideas from quantum mechanics and special relativity. Quantum electrodynamics is an example of a quantum field theory, in which the electromagnetic field is quantized and the quanta are photons. Quantum field theory also applies to ordinary matter - there are electron fields for example, with the quanta interpreted as the electrons. In quantum field theory, quanta may be created or destroyed as the field becomes more or less excited.
Relevant LinksA note on powers of ten and significant figures
|S207 The Physical World|