The Medium Underlying Lorentz Symmetry reconstructs the full mathematical structure of Einsteinian relativity from a physical medium: a frictionless scalar-pressure ether described by the field Ψ(x,t). Instead of postulating the invariance of c and Lorentz symmetry, the analysis shows that both emerge from the finite reorganisation speed of this medium. The Lorentz factor, relativistic kinematics, energy–momentum relations, and gravitational weak-field optics are recovered without invoking mass or geometric axioms. Einstein’s formalism remains valid, but its ontology is reversed: relativity becomes the macroscopic behaviour of a coherent pressure medium rather than a primitive geometric postulate.
Date: Dec 1, 2025
Author: Carlos Omeñaca Prado
ORCID: https://orcid.org/0009-0001-9750-5827
Resource type: Preprint
Publisher: Zenodo
License: CC BY-SA 4.0 International