All electrons, nucleons, and other particles or quanta (because quantum mechanics is applied to all particles, these should be known as quanta) undergo a persistent spin motion without possessing any infinite energy source, and therefore, they should have a unique structure that provides their persistent spinning, as well as their other properties that they display. Additionally, because nothing in nature occurs without a reason or purpose, there should be an explanation for the persistent spinning motion. This study determines the purpose behind the persistent spinning motion of quanta, their unique structures, and properties. The results of the determination of the purpose, named “a new quantum theory”, provide very clear and complete explanations for all the phenomena generated due to quanta. Some such phenomena included in this study are: 1) the interference and diffraction of photons and electrons; 2) spectroscopy; 3) transmittance T, which is finite for particles possessing energy E < V0, when V0 is the energy of the potential barrier; 4) rate reduction of increasing velocity in accelerating electrons after they have attained their relativistic velocity; 5) acquisition of elliptical orbits by orbiting electrons despite moving in a spherically symmetric field, and conservations of their energy, momentum, and spin angular momentum.