Saturn hosts a system of 22 satellites, the largest of which is Titan (smaller than Ganymede, larger than Mercury). Titan has a low density which means it is any icy world.

Titan has a thick, N₂ atmosphere containing a dense smog layer which blocks our view of the surface. The surface pressure is 1.5 x Earth's. Atmospheres are favored in worlds with strong gravity (massive) and with slow moving molecules (cold, heavy molecules).

The atmosphere does not contain water or oxygen (at 94^oK it is too cold for H₂O ices to sublimate), but there are large quantities of methane, CH₄, which forms ethane, C₂H₆, and other organic molecules through reactions powered by solar UV light and energetic particles carried by Saturn's magnetic field.