Originally Posted by Monsieur_DeLarge
Tidal locking is a consequence of distance, the bodies' masses, and time. Although the moon is much smaller than the sun, its closer proximity means it exerts a greater tidal influence overall (about 2.5x greater, as far as I remember), so the moon has been locked to the earth first.
I see, this is a consequence of the tides. In addition, given the same tidal force, it is much easier to phase lock the Moon to the Earth, than the Earth to the Sun since the moon has only 1% of the mass. Makes sense.
That actually suggests that eventually Earth will be phase-locked to the Sun and the seasons will disappear. In fact, now I remember reading that somewhere, perhaps some sci fi.