The Einstein-Aether limit

Any theory with a physical vacuum must explain why experiments have not detected it. In RSI's Preferred-Frame effective field theory, two stiffness coefficients, A and B, describe how the medium responds to disturbances in time and in space. They set the speed of light through c = √(B / A), so B/A = c², which is unity in units where c = 1. Because LIGO saw gravitational waves and light arrive nearly together, gravity and light must share this speed to about one part in 10¹⁵.

RSI recovers the standard Post-Newtonian test values. It reproduces the 1.75 arcsecond deflection of starlight by treating mass as a density shadow. The preferred frame of the medium is hidden from detectors like Michelson-Morley because rulers and clocks built of knots adjust to uniform motion through it, as in the theory of Lorentz and FitzGerald completed by Henri Poincaré. Measurements limit the preferred-frame parameters α₁ and α₂ to a few parts in 10⁵ and 10⁹, and RSI must stay within those limits.

Whether there are deviations at extreme speeds or cosmic scales, such as extra Field-Drag on particles moving against a 1.5° universal torque, is an open question. Precision tests have found no such effect, so any deviation must be extremely small, and RSI does not state one as a prediction.