This note reports flat galactic rotation curves coinciding with observation and originating in Laplace's classical field equation. Dark matter, identified with a primordial fluid populating the entire universe, is represented by the homogeneous Klein–Gordon equation (KGE). The key element is the novel solution for the KGE discovered by the leading author in 1994, expressed as a permanent background -potential plus an entangled -potential where time and distance appear as a ratio. The -potential may be viewed as solution to a non-homogeneous Laplace equation, for which the general solution contains in addition to Newton's 1/r potential a new logarithmic Zwicky potential overlooked thus far. The ensuing 1/r-Zwicky force predicts the observed flat galatic rotation curves exhibiting the observed limiting speed at long distance.