Under the hypothesis that the physical space consists in a finite, continuous, fluid, incompressible substance, and that such a substance (the plenum), though destitute of mass, is made cohesive by an intrinsic kinetic viscosity, a simple analysis of possible oscillations of the plenum leads to conclude that the oscillatory motion is transmitted by transverse waves, whose propagation speed and frequency along with the wave amplitude decrease with the distance from the source-wave.
    Besides, the analysis suggests that the wave propagation occurs through discrete "pulsating packets" of semi-waves spaced by semi-wave intervals, and that the distances traveled by the waves cannot exceed limits fixed by the joint influence of gravitational fields and the plenum's kinetic viscosity.