There are five forces of nature known so far:
- Gravity (a universal force that pulls and pushes on energy and momentum [according to Einstein, who generalized Newton’s notion that gravity pulls on mass], and which holds planets, stars, planetary systems and galaxies together). Gravity is associated with the gravitational field and a not-yet-observed particle called the “graviton”.
- Electromagnetism (including both electric and magnetic forces, which pull and push on particles that carry electric charge, and holds atoms together). Electromagnetism is associated with electric and magnetic fields and with the particle of light, the “photon”.
- The Strong Nuclear Force (a force that pulls and pushes on quarks, anti-quarks and gluons, and holds protons and neutrons together; a residual version of this force holds atomic nuclei together). This force is associated with the fields and particles called “gluons”.
- The Weak Nuclear Force (a force which affects most known particles but is too weak to hold any known thing together; its main effect is to cause many types of particles to decay to other particles, and to allow production and observation of neutrinos.) This force is associated with the fields and particles called “W” and “Z”.
- The Higgs Force (an extremely weak force, not yet observed, which we expect to be present, now that a [and perhaps the] Higgs particle has been discovered and the existence of the Higgs field thereby confirmed.) The Higgs force is of course associated with the Higgs field and particle.
So here are some relevant links:
- The strengths of the forces — what do “strong” and “weak” really mean to particle physicists?
- Why is there a particle and a field associated with each force? (Coming soon)