A New Anomaly of Keplerian Motion

A new anomaly of Keplerian motion, projective anomaly, is derived. The anomaly is derived from a resolution of one of the singularities of Keplerian motion from the viewpoint of projective geometry. Using the projective anomaly, every kind of Keplerian orbit—circular, elliptical, parabolic, hyperbolic, and two-body collisional linear orbit—can be treated in a unified way as a quadratic curve in the projective space in two dimensions. The projective anomaly is further shown to be an instance of a generalized anomaly.