Why Is the Moon Synchronously Rotating?

If the Moon s spin evolved from faster prograde rates, it could have been captured into a higher spin orbit resonance than the current 11 resonance. At the current value of orbital eccentricity, the probability of capture into the 32 resonance is as high as 0.6, but it strongly depends on the temperature and average viscosity of theMoon s interior. A warmer, less viscous Moon on a higher eccentricity orbit is even more easily captured into supersynchronous resonances. We discuss two likely scenarios for the present spin orbit state a cold Moon on a low-eccentricity orbit and a retrograde initial rotation.