[简答题]Relativity theory has had a profound influence on our picture of matter by forcing us to modify our concept of a particle in an essential way. (46) In classical physics, the mass of an object had always been associated with an indestructible material substance, with some "stuff" of which all things were thought to be made. Relativity theory showed that mass has nothing to do with any substance, but is a form energy. Energy, however, is a dynamic quantity associated with activity, or with processes. (47) The fact that the mass of a particle is equivalent to a certain of energy means that the particle can no longer be seen as a static _object, but has to be conceived as a dynamic pattern, a process involving the energy which manifest itself as the particle’s mass.
(48) This new view of particles was initiated by Dirac when he formulated a relativistic equation describing the behavior of electrons. Dirac’s theory was not only extremely