The imaging team's conclusion was supported by the temperature readings from Cassini's infrared spectrometer: Although the surface temperatures were far below freezing, the readings showed relatively warm spots in the south polar region, centering on the tiger stripes. Scientists traced the internal heating patterns that could create such warm spots, and concluded that temperatures could be above freezing mere yards beneath the surface.
"It can be warm enough 10 meters or so beneath the surface," Porco explained, "and there's enough pressure to keep liquid water stable at that depth."
Still more supporting evidence came from an analysis of the ice surrounding the "tiger stripe" cracks. That ice was amorphous and virtually crater-free, indicating that it welled up relatively recently.
Cassini's images showed that the geysers rose hundreds of miles above the surface. Based on the imagery, researchers concluded that most of the ice crystals fell back to the surface as snow. Some of the ice escaped Enceladus' gravity field to become part of a wide, thin ring of Saturn known as the E ring.
