What Is Gravity? From Emergent Mass to Thermodynamic–Geometric Dynamics in the DK-RD2 Framework

Gravity is commonly understood as a purely attractive interaction acting universally on all forms of mass–energy and governing the large-scale structure of the Universe. Despite its empirical success, the fundamental question, What is gravity? remains unresolved. In this work, we propose a unified framework in which gravity is not a fundamental interaction, but an emergent phenomenon arising from the interplay between mass formation, spacetime geometry, and thermodynamic evolution. Within the DK-RD2 framework1, gravity is described through a thermodynamic–relativistic effective coupling: Gₐᵦ(T, v) ≈ G₀ · 1 + α · (v²/c²) · (T₀/T) In which the gravitational strength depends on both the thermodynamic state and relativistic dynamics of the cosmic medium. The factor α represents an effective geometric projection coefficient arising from the layered structure of spacetime, encoding the partial coupling of multiple underlying configurations to the observable large-scale dynamics. This formulation naturally reproduces late-time cosmic acceleration without invoking a cosmological constant or additional dark components, and is consistent with multiple independent observational probes, including Type Ia supernovae, DESI expansion measurements, cosmic microwave background angular structure, gravitational lensing, and compact gravitational systems exhibiting highly localized dynamical behavior. Within this framework, mass corresponds to scale-localized geometric structures, while gravity emerges when these structures lose isolation and couple to the global geometry of spacetime. Cosmic acceleration is interpreted not as the effect of an external component, but as the large-scale thermodynamic limit of a continuous mass–energy–temperature cycle. The DK-RD2 framework, therefore describes gravity as a macroscopic manifestation of evolving thermodynamic and geometric conditions, in which the observed interaction reflects a projected and scale-dependent coupling of underlying configurations, rather than being fundamental, gravity emerges as a projected macroscopic interaction arising from the thermodynamic organization of energy This approach provides a coherent and testable reinterpretation of gravity, linking microphysical structure, spacetime geometry, and cosmological dynamics, and offering clear observational signatures that make the model directly falsifiable. in this sense, gravity is not a pre-existing force acting on mass, but an emergent interaction that becomes physically meaningful when energy attains sufficient localization and stability An important aspect of this work is that all figures, statistical calibrations, thermodynamic reconstructions, and observational comparisons were implemented directly through reproducible Python source code developed for the DK-RD2 framework.