Tidal acceleration is an effect of the
tidal forces between an orbiting
natural satellite (i.e. a moon), and the
planet (called the primary) that it orbits. It causes a gradual recession of the satellite's orbit away from the primary, and a corresponding slowdown of the primary's rotation. The process eventually leads to
tidal locking of first the smaller, and later the larger body. The Earth-Moon system is the best studied case.
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The frictional heating of the interior of a satellite (e.g. the moon) due to flexing caused by the gravitational pull of the parent planet (e.g. Earth). It is the reason the moon gradually stopped spinning and now presents one face to the earth.