c 1 c 2 c 1 + L ′2 . For nonvanishingñ, E, andL the maximum of the parabola is no longer located at ξ = 0 or, equivalently, the zeros are no longer symmetric with respect to ξ = 0. Only for vanishingñ, E, orL both cones are symmetric with respect to the equatorial plane.The ϑ-motion can be classified according to the sign of c 2 − L ′2 :1. If c 2 − L ′2 < 0 then Θ ξ has 2 positive zeros for L ′ Eñ > 0 and ϑ ∈ (0, π/2), so that the particle moves above the equatorial plane without crossing it. If L ′ Eñ < 0 then ϑ ∈ (π/2, π). TO CEO EO D 0 C B O BO EO ⋆ ⋆ ⋆ EO D 0 CBO ⋆ ⋆ ⋆ ⋆ ⋆ BO EO (b) Taub-NUT space-time II. The CEO (red) starts at the horizon r−, the CBO (blue) starts at the horizon r− and terminates at the horizon r+. FIG. 10: Topology of orbits in Carter-Penrose diagrams of Taub-NUT space-time. The orbits drawn in black are standard orbits with infinite proper time, the orbits in red, blue, and green are geodesically incomplete.crossing one of the horizons r − or r + , it cannot cross this horizon a second time, because ψ(γ) diverges there. At