Synchronous, Nonsynchronous and Negative Rotations: How Spin and Gravity Orchestrate Planetary Motions

Abstract

This study identifies the unique features accompanying the phenomenon of synchronous rotation of the major (proximal) satellites of the gas giants and the earth’s moon, and the special features leading to the ‘negative’ rotation of Venus, Uranus and Pluto, as well as the most peripheral small satellites of the gas giants. Such features help us understand how these phenomena occur but also, by combining all of the observations help explain other (regular) planetary motions as well. In the synchronously rotating satellites, the salient features are the satellites’ low axial tilts and both the orbital speed and the axial rotation speed increasing with proximity to the mother body. In “negative” rotation, axial tilts are in excess of 120° and the axial rotation speeds are significantly delayed; this delay is most pronounced in Venus, which has an axial tilt of -174°. A scrutiny of the orbital parameters of all the satellites of the gas giants alone will yield sufficient data to propose a working hypothesis of how mutual gravitation, combined with spin (axial rotation and orbital motion), the distance from the mother, and centrifugal force can explain all motions. It confirms our belief that the process of planetary motions is a continuum from the synchronous, through degrees of non-synchronicity (or regular orbits), to the negative rotations, all depending on the degree of influence from mother bodies, as a product of distances from them. Thus, the nearest large satellites with the least axial tilts display synchronous rotation. Those satellites that are intermediate in distance from the mother show nonsynchronous axial rotation and correspondingly slower orbital speeds. The small peripheral satellites display axial tilts over 120 degrees and rotate negatively. In all these orbital motions, centrifugal force is the crucial restraining influence; lest, the orbiting bodies will tend to fall into the mother bodies. How all these pieces of the puzzle fit together in the orderly movements of bodies in the universe is the underlying theme of this article.