Fundamental Forces

The basic forces in nature Click on image for full size (32K GIF) Image courtesy of Contemporary Physics Education Project

The interactions in the Universe are governed by four forces (strong, weak, electromagnetic and gravitational).

Physicists are trying to derive a unified theory that would describe all the forces in nature as a single fundamental law. So far they have succeeded in producing a unified description of the weak and electromagnetic forces, but a deeper understanding of the strong and gravitational forces has not yet been achieved.

Quantum physics describes the mutual effect of forces on particles by the "exchange" of other particles. For example, electrically charged particles attract or repel each other by emitting and absorbing photons, which carry the electromagnetic interaction.

Table courtesy of University of Guelph, Guelph, Ontario (Cananda)