Tidal Evolution of the Moon 2: Cassini State Transition

Animation of relative orientations of lunar figure and orbit during the Cassini state transition. The Moon is seen from the direction of the ascending node of lunar orbit, with the ecliptic plane (i.e. the Moon’s Laplace plane at this time) parallel to the horizontal axis. The red arrow shows the orientation of the Moon’s orbit normal. At first the Moon’s orbit normal and spin axis are on the same side of the normal to the ecliptic, indicating that the Moon is in Cassini state 1. Once the Cassini state 1 is