Space is a combination of small and large planets

“Braiding defies the laws of orbital me¬chanics for several reasons,” he says. “But obviously these rings are doing the right thing. I guess we just don’t understand the laws very well.”

Attention is about to be drawn away from the rings. Overnight the closest images of Titan have come in. Faces are long. Clouds totally veil the surface. The Titan story will not be told in pictures. But today begins a dizzying series of closest encounters with Saturn’s other named moons.

Planets2013 Mimas, Enceladus, Tethys, Dione, Rhea. Not to mention Hyperion, Iapetus, and Phoebe. “Too many moons,” grumbles moon specialist Larry Soderblom. Until this week most of Saturn’s named moons were merely points of light through a telescope. Project scientists cannot even agree on pro¬nunciation. Some say Mee-mas, some say My-mas. Some make Enceladus (En-SELL¬a-dus) sound like a Mexican dish.

These bodies are much smaller than Earth’s and Jupiter’s large moons, or their brother satellite Titan, yet larger than most asteroids and the tiny moons around Mars, Jupiter, or Saturn.
They should be made from roughly the same material—dust and ices—as comets. They should be too small to have much of the radioactive rocky material that in larger bodies heats up the interior and generates geologic processes such as volcanism. These watery moons should have frozen fast soon after forming. They should be heavily pocked with craters, the scars of countless random collisions with celestial debris. There is no reason to suspect they are any¬thing but big dirty snowballs.

space full of stars

Voyager will not come close enough to Hyperion and Iapetus to reveal much. It will not even photograph Phoebe, the farthest out. Phoebe has long been known to travel in the opposite direction from Saturn’s other moons. It is most likely debris captured by Saturn’s gravity as it passed by.

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