V3.75 Unified Spacetime Theory Foundations: The Mechanical Origins of Spacetime - Unifying Forces and Deriving Lorentz Symmetry

I will be removing ALL instances of language used to describe gravity as sourced only in bulk compression. This does not change the equations or math. It is an error on my part after working on the bulk sector of the moduli for the theory. I conflated the description of gravity with the bulk moduli, and this is not correct. I will need to update my papers to reflect this clearly. I apologize for the error, and will be updating all papers posted thus far. - This resulted in the V5.0 new version:  https://doi.org/10.5281/zenodo.17887509

-NEW Version 4.10, old V3.75- Removed any equations and content with logitudinal waves and wave speeds. There are no longitudinal waves in UST, Gravity waves are shear sector only. Gravity is the refractive index/metric pattern of the continuum that encodes the USEMP-induced softening of the elastic moduli, sourced by mass-energy in the bulk, shear, and torsional sectors of the configuration field. Compression is the state, softening is the response, and “gravity” is the emergent geometry defined by that response, not a fluctuating wave field and not a graviton-mediated force. This is why, in UST, gravity is not an additional force sector alongside electromagnetism with its own particles or propagating waves; it is the constitutive softening of the same medium whose transverse/torsional excitations form the EM sector.

Abstract
Unified Spacetime Theory (UST) treats spacetime as one continuous medium. Its behavior explains gravity and electromagnetism (and all forces and physics of the Universe to be revealed in future work), and it does so with a single, common wave speed (the light-cone speed).

The framework is deliberately simple: it uses only measurable quantities and adds no extra dimensions, no speculative symmetry stacks, and no exotic particles. UST is not a patchwork of existing theories; it aims to reproduce known physics mechanically, within today’s measurement reach and within its own framework (built from scratch). In familiar limits, the usual laws reappear. Stable, localized patterns in the medium act like sources by carrying energy and momentum in ways we normally attribute to mass, charge, and current.

What this paper does
It spells out the assumptions and scope, build a clean time-evolution system, and proves two essentials: causality and positive energy. We then recover standard weak-field gravitational tests and Maxwell’s equations in a vacuum, with causal propagation at c. Finally, we provide technical and numerical checks so others can audit and reproduce the results.

Minkowski emerges: UST doesn’t start by assuming a Minkowski spacetime (the usual flat, geometric backdrop). Instead, it begins with a single continuous medium that has ordinary material properties, stiffness and inertia, described by bulk, shear, and torsion moduli (a generalized Hooke’s law via the Unified Spacetime Elastic Modulation Principle, USEMP) and by density. These properties set how fast signals move and how disturbances behave. When the medium is uniform and gently excited, its waves share a single universal speed and familiar Lorentz behavior appears on its own. In that calm limit, the coordinate description you’d use to track those waves is indistinguishable from Minkowski’s, so flat spacetime emerges as a consequence, not an assumption. When the medium’s properties vary, softening or stiffening with energy and configuration, paths bend and clocks shift; that’s gravity in this picture. In short, UST starts from measurable material parameters of a spacetime medium and derives the Minkowski picture as the simplest, low-stress limit, rather than building the theory on Minkowski from the start.

Coming Next: The foundational series “The Mechanical Foundations of a Unified Spacetime” from UST is organized as a ten-paper series, all built on the same mechanical medium developed here. After the foundations (USEMP) and the Lorentz-invariant formulation, and Spin 1/2 paper, the next papers, in order, are Black Holes and Quantum Gravity: The Mechanical Origin of Hawking Radiation, Dark Mass, History of the Universe, The Strong Force, The Weak Force, Emergence of Quantum Dynamics: Deriving the Schrödinger Equation from Continuum Mechanics, and finally The Particle Zoo: Deriving the Mass Spectrum from Solitonic Resonance. Together they extend the same underlying medium to black holes and Hawking radiation, dark mass, cosmology, the strong and weak interactions, the emergence of quantum dynamics, and the full particle zoo, always with the goal of giving a minimal, reproducible and testable mechanical account of observed physics rather than stitching together separate theories by hand.

Spin 1/2 paper

https://doi.org/10.5281/zenodo.17795865

Black Hole and Quantum Gravity paper

https://doi.org/10.5281/zenodo.17804079

Contact: jared@ustphysics.org