1. Summary 2. The law of difference of gravitational potentials 3. The effect of the law of difference of gravitational potentials 4. Gravity-space-time reference system 1. Summary For centuries, scientists have been preoccupied with the search for a reference frame in the Universe that could unambiguously determine, for example, the Earth revolves around the Sun, or vice versa. Neither the Ptolemy system nor the Copernican system possess such uniqueness. Kepler’s laws also do not clarify this issue. Einstein's theory of relativity suggests the equality of both points of view. But for many researchers, the question remained open. And finally, uniqueness, as if, appeared. Uniqueness is formed by the difference of gravitational potentials 2. The law of difference of gravitational potentials It is known that a system of two cosmic bodies moving in a gravitational field forms a rotation point called the center of mass, where a body with a larger mass is closer to the rotation point than a body with a smaller mass. And this behavior of bodies is a known fact. But this fact still has not received due consideration. If 99.866% of the mass of the solar system is concentrated in the mass of the sun, then it is clear that the sun is the center of rotation for everything that revolves around it. Moreover, the center of rotation is not a relative, but an absolute center of rotation, meaning that not a single body of the solar system, under any circumstances, can become the center of rotation of the solar system. Thus, the difference of gravitational potentials forms an objective and absolute (for a given system) center of rotation, forming a privileged reference frame, a privileged state of motion, where bodies with less mass rotate around bodies with more mass, and there are no such systems where it could be vice versa. In view of the importance of this phenomenon (the formation of privileged reference frames by the difference of gravitational potentials), we have elevated thi ... Read more