Modern physics has suffered a century-long fatal misconception: it fails to strictly distinguish between the body of a force field and its field source, and mistakenly regards the speed of field intensity variation generated by source motion as the propagation speed of the field itself. This error has led to a complete set of flawed theories including the claim that electromagnetic and gravitational waves propagate at the speed of light, as well as the hypothesis of various force-carrying messenger particles. This paper clarifies the fundamental physical logic: there exist only three fundamental forces in the universe, corresponding to three types of force fields respectively—the gravitational field, the electric charge field, and the strong nuclear field. A field is defined as the spatial range over which a fundamental force acts. All force fields exist instantaneously across all space without propagation processes or intrinsic motion speed, and force interactions occur with zero delay. The intensity of every force field obeys the inverse-square law of distance; the greater the distance from the source, the faster the force attenuates. A field source is the entity that generates a corresponding force field. Macroscopic field sources include all celestial bodies and massive bulk matter, while microscopic field sources consist of three elementary particles: protons, electrons, and neutrons. Field sources are material entities, yet they are physically distinct from the force fields they produce. Each field source possesses an independent, variable motion speed. The field itself has no speed and only shifts synchronously and instantaneously following the position of its source. The observed speed of field disturbances is exactly equal to the motion speed of the source. Charge sources such as electrons and protons can move at speeds approaching the speed of light, whereas celestial body sources travel far slower. Such disparities in disturbance speed originate solely from the sources rather than the fields themselves. Distinctions based on action scale: gravitational fields only produce observable macroscopic effects; charge fields (electromagnetic fields) exist universally across both micro and macro scales, underlying atomic and molecular structures as well as macroscopic phenomena such as generators and planetary magnetic fields; the strong nuclear field only exerts measurable effects within the tiny scale of atomic nuclei. When analyzing physical systems, forces are selected according to scale: macro analysis prioritizes gravitation and electromagnetic force, while nuclear microanalysis focuses on electromagnetic force and the strong nuclear force. This paper delineates clear boundaries between fields, field sources, and field disturbances, correcting long-standing fundamental paradigm errors.
Jiaqing Yan (Sun,) studied this question.