The External Stress–Energy Principle: A General-Relativistic Framework for Understanding Why Long-Range Fields Determine Observable Gravity A Conceptual Clarification, Not a Modified-Gravity Theory

This work presents a general-relativistic principle explaining how the external gravitational field of a physical body is determined by the support structure of its stress–energy tensor. By separating confined microscopic stresses from externally supported long-range stresses, the paper shows that only the latter contribute appreciably to gravitational multipoles beyond the monopole term. The analysis is fully consistent with Einstein’s equations and relies on standard multipole expansion, compact-support arguments, and linearized curvature. Examples include atoms, solids, plasmas, and astrophysical matter distributions. The principle provides a unified and physically intuitive interpretation of why macroscopic electromagnetic rigidity, rather than confined QCD stresses, controls the shape of gravitational fields.