We present a novel interpretation of dark matter within the five-dimensional hydrodynamic spacetime framework. Rather than exotic particles or modifications to gravity, we propose that dark matter consists of ordinary matter temporally displaced from our "present"—matter that exists at slightly different time coordinates due to local variations in time density during the early universe. The key insight is that gravity and electromagnetism couple differently across temporal displacement. Gravity, as spacetime curvature, operates across all time coordinates—mass curves spacetime regardless of "when" it exists. Electromagnetic interaction, however, requires particles to share the same temporal moment for photon exchange. Matter displaced from our "present" is therefore gravitationally interacting but electromagnetically invisible. We derive the observed ratio of visible matter to total matter (5: 27, or approximately 5/32 = 15. 6%) from a Gaussian distribution of temporal displacements. The distribution width σₜ and the electromagnetic interaction window τₒbs (equal to the electron Compton time τₑ = ℏ/ (mₑ c²) ) determine this ratio through the error function. A cosmological restoring force with characteristic timescale τₖ ≈ 2/ (3H₀) causes the distribution to narrow over cosmic time, explaining why the visible fraction has increased since the early universe. We trace the origin of temporal displacement to quantum fluctuations in time density during the early universe, with freezing occurring at temperatures around 100 TeV. This framework makes the striking prediction that dark matter direct detection experiments will never succeed, as temporally displaced matter cannot physically collide with detectors in our "present. " Only gravitational effects remain observable. We also propose a geometric interpretation of lepton generations (electron, muon, tau) as bound states involving different degrees of w-compression, explaining both their mass hierarchy and their instability through the weak binding of neutrino-like components. This is the third paper of a trilogy. The foundational framework is developed in "Five-Dimensional Hydrodynamic Spacetime: Time Density and Dark Energy Complementarity. " The quantum mechanical implications are developed in "Quantum Mechanics from Five-Dimensional Spacetime: A Geometric Origin of Probability. "
Shota Kisida (Fri,) studied this question.