PHYSICS:THEORY OF RELATIVITY Space time tells matter how to move;matter tells space time how to curve-John Archibald wheeler Time is an illusion ,albeit a very persistent one- Albert Einstein Special theory of relativity This was the first theory given by Albert Einstein about relativity. It can be understood clearly if we consider the universe to consist of fields in a background of space time. The fields undergo wave motion and create particles according to the rules of quantum field theory. According to the theory the velocity of light waves is the maximum velocity allowed in space time. All matter waves have velocity less than light waves which is massless. A consequence of this is that as matter waves gain velocity and energy and approach speed of light the velocity cannot increase further. Now extra energy given to the waves decreases the momentum and wavelength. This leads to length contraction. Again frequency of the wave decreases leading to slowing of time. ...