What are the four fundamental forces and how are they related? How do they differ?

Maxwell united electricity and magnetism to form electromagnetism, which has a long range and describes both light and the forces between charged particles. The electromagnetic force describes the interactions between charged particles.

The weak nuclear force operates at a very short range and describes radioactive beta decay, which is the process by which a proton is converted into a neutron, an electron, and an electron anti-neutrino. It also describes the conversion of a positron into a neutron, an electron, and an electron neutrino.

The electroweak theory unites the weak nuclear force and electromagnetic forces, which are highly disparate at low energies and unified at very high energies.

The strong nuclear force that remains after protons and neutrons are bonded into atomic nuclei is known as the residual strong nuclear force. This force is short-lived because it is essentially a component of the color force that binds quarks into baryons and mesons.

The unification of the electroweak and color forces into a Grand Unified Theory (GUT) is one of the objectives of contemporary physics.

According to General Relativity, gravity is the curvature of four-dimensional spacetime, but it is not a force per se—as long as masses and velocities are not too high.

The creation of a Theory of Everything (TOE) that unifies gravity and a GUT is an even greater objective in physics.

The four fundamental forces are gravity, electromagnetism, weak nuclear force, and strong nuclear force. Gravity acts on mass, electromagnetism involves charged particles, weak force mediates particle decay, and strong force binds quarks within protons and neutrons. They differ in their respective mechanisms, ranges, and strengths.