The heat inside Enceladus...

This image shows the warmest places in the South Polar Region of Enceladus. The unexpected temperatures were discovered by Cassini's Composite Infrared Spectrometer during a close flyby on July 14, 2005. The image shows how these temperatures correspond to the prominent, bluish fractures dubbed "Tiger Stripes". Such "warm" temperatures (91 and 89° Kelvin - about minus 296 and minus 299° Fahrenheit - are unlikely to be due to heating of the surface by the feeble sunlight striking Enceladus' South Pole. They are a strong indication that internal heat is leaking out of Enceladus and warming the surface along these fractures. Evaporation of this relatively warm ice probably generates the cloud of water vapor detected above Enceladus' South Pole by several other Cassini instruments. Scientists are unsure how the internal heat reaches the surface. The process might involve liquid water, slushy brine, or soft but solid ice.