Fundamental force

There are four fundamental forces in the universe, sometimes called fundamental interactions. They are called 'fundamental' because they cannot be reduced to anything simpler.

• Gravity and electromagnetism are experienced by people in their everyday life. A complete description of the forces requires advanced physics.
  • The gravitational force is due to the curvature of spacetime, described by Einstein's general theory of relativity.
  • Electromagnetic force is due to electric charge. Charge causes electric force and movement of charge causes magnetic force.

• The strong and weak interactions produce forces at minute, subatomic distances and govern nuclear interactions. These forces are the
  • The strong force binds protons and neutrons together, keeping atoms intact.
  • The weak force causes beta decay.

It is thought by most physicists that three of these forces (electromagnetism, the weak force, and the strong force) become a single force under very high temperatures. This idea is known as the grand unification theory.