[Note: The edits of this version_28 are typed in magenta color font] Abstract This work develops a quantitative formulation of Push Gravity (PG), a physical framework in which gravitation arises from momentum transfer by an omnipresent flux of discrete particles, rather than from action at a distance or from spacetime curvature. Building on a small set of primary principles, the theory recovers the classical inverse-square law of gravity for stationary bodies in the steady state, while extending gravitational behavior beyond the weak-absorption regime assumed in earlier push-based models. A central result is that gravitational interaction depends not only on total mass but on an absorption-controlled effective mass, which may differ from the real (substantial) mass of a body due to self-shielding effects. The gravitational constant emerges as a derived quantity linked to a mass-attenuation coefficient, allowing the inverse-square law to be locally preserved even when effective mass varies with internal structure and compactness. The theory predicts a universal maximum gravitational acceleration associated with saturation of momentum transfer, beyond which additional mass accretion does not increase surface acceleration, but increases the range of the gravitational field. The framework provides explicit treatments of internal and external gravitational fields of layered spherical bodies, reformulates gravitational superposition, and clarifies the operational meaning of the equivalence principle. Matter, inertia, and mass acquire well-defined physical interpretations rooted in momentum exchange and geometry. Extensions to moving bodies suggest that many empirical relations of special and general relativity may continue to operate as effective descriptions within a broader PG ontology, without being foundational to it. Push Gravity further admits analogous momentum-transfer descriptions for electromagnetic and nuclear interactions, indicating a potential route toward unification of fundamental forces through a common absorption-driven mechanism. Applications developed in this work range from particle structure to astrophysical compact objects and cosmology. In particular, the theory predicts that gravitational redshift can become extremely large for sufficiently compact systems without invoking event horizons or spacetime singularities. This leads to a novel redshift–distance relation and to the existence of a minimum mass threshold for a true black hole, defined operationally by complete suppression of electromagnetic escape. Taken together, these results suggest that gravitational redshift may play a far more significant role in astrophysics and cosmology than conventionally assumed, challenging the necessity of universal expansion as the sole origin of observed cosmological redshifts. The theory is presented as a self-contained physical framework poised for further analytical development and experimental interrogation. Beyond gravitation, the push principle has been extended to other interaction fields within the broader body of work. These developments indicate that a unified push-based description of fundamental forces may be achievable in principle, forming the basis for a prospective quantum push field theory (QPFT).

ERRATUM: In versions v1–v28, a typographical error appeared in Eq. (18), where OM should read PM. The correction is purely notational and does not affect any derivation or result. To assist returning readers, the edits of the current version v28 are typed in magenta color font. The use of different color with every new version makes it easier to follow the timeline of developments. It is recommended to follow this timeline, until a later version is properly compiled to avoid any remaining duplications or even some inconsistencies. The Python codes for various computations are now provided in https://doi.org/10.5281/zenodo.7951860. Please email comments to the author. Feedback on this working book is welcome whether on scientific queries or on editing or oversighted errors to assist in the progress of the work.