Topology in the Solar System via projective geometry
          C.A. Altavista
          Facultad de Cienoias Astronomicas y Geofisicas



  It is shown in this paper that the so called cross-ratio relationship
of the Projective Geometry can be applied within the context of the
instantaneous motion of the two-body problem. Topology is introduced,
then, in view of the topological character of the projective space.