Galaxy Rotational Dynamics and the Logical Inconsistency of the Dark Matter Hypothesis (Revised)

Traditional galaxy rotational dynamics directly applies the Suncentric singlecenter gravitational model of the solar system, ignoring the inversesquare law of gravitational attenuation and the basic characteristics of the spatial mass distribution in galaxies. It incorrectly assumes that stars in the outer regions of galaxies are governed solely by the gravitational pull of the galactic core, and thus introduces “dark matter” to compensate for the theoretical gravitational deficit. This paper theoretically demonstrates that the mass of the solar system is highly concentrated, and gravitational interactions among planets are negligible, whereas galactic mass is diffusely distributed, so the gravitational effects of all matter in the galaxy cannot be ignored. Galactic rotation is maintained by the combination of shortrange chain gravity and universal gravitational superposition, with no theoretical need to introduce dark matter. The dark matter hypothesis suffers from internal logical inconsistencies and conflicts with established gravitational theory, arising essentially from theoretical bias due to oversimplified modeling. The outermost stars in a galaxy are mainly attracted by their immediately inner neighboring stars as the primary gravitational source; therefore, the speed of outer stars should not exceed that of their inner sources. They can move slightly slower or at nearly uniform speed, ensuring longterm structural stability of the galaxy. This constraint also explains why galaxies exhibit spiral arm structures rather than rigidly rotating structures.