A New Gravitational Model of Spiral Galaxies Based on Newtonian Mechanics

Abstract

　In the spiral galaxies, including the Milky Way, a flat rotation curve V(r) thatdoes not obey Kepler's law was discovered in the early 1930s and became a great mystery. Initially, this could not be explained correctly by Newtonian mechanics, and a hypothesis was proposed that there was a new, unidentified dark matter that increased the gravity. However, there is still no conclusive evidence, although the indirect studies of cosmic background radiation and gravitational lensing effect support this hypothesis. In this study, I focus on the characteristic spiral shape of galaxies and propose a new gravity model (basic equation) based on Newtonian mechanics. This model predicts the existence of a new centripetal force, the interstellar force T(r), which is different from the conventional gravity in the spiral motion. In the verification, an analytical solution V(r) was derived based on the new basic equation and compared with the observed data. As a result, the new model was successfully verified for the first time with perfect agreement within ±5% for the entire region from the bulge edge to the solar system. It was found that the centripetal force of the disk part forms a new force, "spiral force" by the spiral motion in addition to the conventional gravity, and that these two forces are generated simultaneously in unison. The spiral force is generated by the macroscopic interaction of Universal gravitation between the stars and manifested by the expansion of the scale to the galactic system, and I believe that it represents a new principle for the generation of gravity that does not exist in the conventional concept. I hope that this new gravitational model (gravity theory) will be utilized as a useful tool for the deeper understanding of the spiral galaxies in the universe in the future.