Mechanism of Planetary Orbital Precession

For over a century, the residual deviation in Mercury’s orbital precession has been regarded as key observational evidence supporting the spacetime curvature view of General Relativity. Within the Newtonian mechanics framework, researchers have incorporated the gravitational contributions from major planets, yet a residual drift of 43 arc seconds per century remains unaccounted for. This residual deviation has long been taken as empirical proof of spacetime curvature around the Sun. Based on the orbital steady state mechanism of the Light Origin Theory, this paper proposes an alternative explanation: the residual deviation originates from intermittent dynamic gravitational perturbations by Earth and Venus. Mercury orbits the Sun in 88 Earth days, Earth in 365 days, and Venus has its own distinct orbital period. The periods of the three bodies are incommensurate. Within one hundred years, only a limited number of close encounter events occur between Mercury and either Earth or Venus. Gravitational perturbation peaks when the two bodies reach their relative minimum separation and becomes negligible at larger distances. These episodic, strongly varying gravitational tugs repeatedly impose lateral torques on Mercury’s orbit. Tiny individual effects accumulate over a century to produce the observed orbital precession. Although traditional perturbation calculations include the gravity of Earth and Venus, they adopt time averaging treatment. Time averaging smooths out intermittent variations in gravitational strength and yields constant, regular external forces. Such averaged forces only alter the geometric shape of the orbit and cannot produce orbit deflecting precession; only instantaneous peak gravitational torques during planetary close encounters can drive precession. While gravitational influences are formally included in the equations, the core physical mechanism generating precession is effectively lost. This hypothesis permits quantitative verification. Astronomers can use long term orbital observational data and known celestial masses to locate the few critical time windows within a century when Mercury reaches relative closest approaches to Earth and Venus, and compute the orbital deflection effect of instantaneous gravitational torques at these encounter moments. If validated by calculation and observation, Mercury’s orbital precession would no longer serve as robust evidence for spacetime curvature, removing this major observational support for that concept. Mercury’s precession could then be fully explained by dynamic planetary gravitational perturbations without invoking the spacetime curvature postulate.