The four fundamental forces that govern all interactions of matter and energy are:
Gravity: Gravity is the force that attracts objects with mass towards each other. It is responsible for the interactions and motions of astronomical bodies, such as planets, stars, and galaxies. Gravity is a long-range force, meaning it acts over large distances. It is described by Einstein's general theory of relativity.
Electromagnetic Force: The electromagnetic force is responsible for interactions between electrically charged particles. It encompasses both electric and magnetic interactions. Electric charges can attract or repel each other, and electrically charged particles can create electric fields around them. Moving charges also create magnetic fields. The electromagnetic force is long-range and is described by classical electromagnetism and quantum electrodynamics (QED).
Strong Nuclear Force: The strong nuclear force, also known as the strong interaction, binds protons and neutrons within an atomic nucleus. It is a short-range force, acting only within the nucleus. The strong force is responsible for holding the positively charged protons together despite their mutual electrostatic repulsion. It is described by the theory of quantum chromodynamics (QCD).
Weak Nuclear Force: The weak nuclear force is involved in processes such as radioactive decay and neutrino interactions. It is responsible for certain types of particle decays, where one type of particle transforms into another. The weak force is short-range, similar to the strong force. It is described by the electroweak theory, which unifies the weak force with the electromagnetic force.
Each of these fundamental forces has distinct characteristics, including their range, strength, and the types of particles they interact with. The four forces are unified in the framework of the Standard Model of particle physics, which combines three of the forces (electromagnetic, weak, and strong) into a single theoretical framework. However, gravity remains separate and has not yet been successfully unified with the other three forces in a complete theory.