The End of the Einstein Era. The Death of Spacetime Geometry.

We present a unified hydrodynamic alternative to Dark Matter and Dark Energy based on Material Space Theory (MST)[1]. By treating the gravitational field as an accelerated flow of a viscous, quasi-superfluid medium into mass-sinks, we demonstrate that galactic rotation curves are the result of an azimuthal viscous drag (vortex). We derive a non-linear scaling law for the effective kinematic viscosity, νₑff ∝ Φ¹.³⁴, which successfully accounts for the diversity of galactic dynamics: from the ”dark-matter-deficient” dwarf galaxies (NGC 1052-DF2) to the declining rotation curve of the Milky Way and the flat curves of massive spirals like M31. Furthermore, gravitational lensing is redefined as a dynamic refraction within the space-velocity field, offering a mechanical explanation for the Bullet Cluster’s mass-offset. Finally, we propose that cosmic expansion is a manifestation of the medium’s negative bulk modulus, where space reacts to compression by expanding. This framework replaces geometric abstractions with a single physical substrate, providing a purely mechanical foundation for modern cosmology.