Electromagnetic External Stress as a Dominant Gravitational Source in Baryonic Matter A Matter-Side Resolution of Dark-Matter Phenomenology Within General Relativity

Gravitational phenomena commonly attributed to dark matter are inferred through dynamical and lensing analyses rather than directly observed. These inferences rely on the implicit assumption that baryonic matter sources gravity solely through its coarse- grained rest-mass energy density. In a nonlinear theory such as general relativity, however, gravitational response need not commute with coarse-graining when matter exhibits long-range correlations. In this work we demonstrate, within standard general relativity, that correlated electromagnetic stress–energy generically produces a non-vanishing variance contri- bution to gravitational sourcing under coarse-graining. By formulating gravitational averaging explicitly and classifying matter stress–energy by interaction range, we show that confined and collisionless contributions are parametrically suppressed, while elec- tromagnetically mediated stresses uniquely survive in the large-scale limit. This result establishes electromagnetic external stress–energy as a derived, rather than imposed, source of effective gravitational enhancement. We further show that, in ionized baryonic matter, electromagnetic coupling natu- rally realizes the conditions required for such external stress–energy, leading to an ef- fective gravitational response exceeding that associated with baryonic rest mass alone. The resulting framework reproduces the phenomenology commonly attributed to colli- sionless dark matter in all observed regimes where gravitational anomalies arise, with- out introducing new matter components or modifying gravitational dynamics. The analysis is conservative in scope, mathematically explicit, and admits clear falsifiabil- ity conditions.