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Pluto's elongated moons

Pluto's elongated moons
Pluto's elongated moons Almost all large or nearby moons in the solar system always keep one face oriented toward their planet; our own moon is one example. This is called "synchronous rotation". It arises because the planet's tidal gravity force—the change in the force across the moon's diameter—damps out the rest of the moon's rotation. Furthermore, when a moon is elongated, the tidal force keeps the moon's long axis pointed toward the planet. This movie illustrates the expected rotation state of one of Pluto's moons. The red moon is enlarged and elongated for illustrative purposes. Mark Showalter, SETI Institute