the.com/tidal locking
why the moon shows you one face and never the other, like a shy date at dinner.
means a moon's rotation and orbit sync up so the same side always faces its planet.
from named for tidal forces: a planet's gravity stretches its moon into a slight egg shape, and friction from that bulge drags the moon's spin until it matches its orbit, then stops changing.
moon's speedtakes 27.3 days to spin once, same as orbit
earth's fateearth is slowly tidal locking to the moon too
far side myththeres no permanent dark side, just a far one
pluto and charonboth locked to each other, mutual staring contest