The fundamental forces, also known as the fundamental interactions, are the interactions through which particles affect one another. They are foundational to our understanding of the physical world.

As of the latest understanding, there are four fundamental forces:

Gravitational Force:

  • Gravitation is a universal force that acts between all masses. Described by Einstein’s General Theory of Relativity, gravitational interactions result from the warping of spacetime caused by mass and energy. Gravity is the weakest of the four forces but dominates at astronomical scales due to its long-range nature.

Electromagnetic Force:

  • The electromagnetic force includes both electricity and magnetism. It acts between charges and is carried by photons. It’s responsible for chemical reactions, the behavior of solid, liquid, and gaseous matter, as well as electromagnetic waves like light and radio waves. It is immensely stronger than gravity and operates at infinite range, though its effects can be shielded or canceled.

Weak Nuclear Force:

  • The weak nuclear force is responsible for beta decay, a type of radioactive decay. It acts at sub-atomic distances and is mediated by W and Z bosons. The weak force is crucial for the nuclear fusion processes in stars, including the Sun.

Strong Nuclear Force:

  • The strong nuclear force, or strong interaction, is the strongest of the four fundamental forces. It binds protons and neutrons together in the nucleus of atoms. It’s mediated by gluons and acts only at very short distances, on the order of nuclear sizes. It overcomes the electromagnetic repulsion between positively charged protons in the nucleus.

Each of these fundamental forces is characterized by its own force-carrier particle and unique governing equations. While the electromagnetic, weak, and strong forces have been unified in the framework of quantum mechanics, gravity remains separate, described by the classical equations of general relativity. A major goal in modern physics is to find a way to unify gravity with the other three forces, leading to a Theory of Everything.