Derivation of the Essence of Gravitation and Interpretation of the Gravitational Constant - Based on the First-Principle Unified Theory of Light Strings

Based on the First-Principle Unified Theory of Light Strings, this paper presents a first-principle derivation of the physical essence of universal gravitation and the origin of the gravitational constant G. Without empirical fitting or additional hypotheses, it explains gravity as an elastic rebound squeezing effect of the light string field disturbed by particles, clarifies the proportional relationship between rest mass and bound frequency, and reveals that G is a derived constant from the light string field's elastic properties.