Dr. Porco further believes that Enceladus's orbit could have been much more eccentric in the past. The greater the eccentricity, the greater the tidal squeezing, and the resulting structural variations produce heat. In this case, the heat would have been saved inside the icy moon, melting some of the ice to replenish the liquid water sea. Dr. Porco continued to explain that "(T)he tidal flexing occurring now is not enough to account for all the heat presently coming out of Enceladus. One way out of this dilemma is to assume that some of the heat observed today was generated and stored internally in the past... (N)ow that the orbit's eccentricity has lessened, the heat emanating from the interior is a combination of heat produced today and in the past."
The Kuiper Belt. Dark, distant, and cold, the Kuiper Belt is the remote domain of an icy multitude of comet nuclei, that orbit our Sun in a strange, fantastic, and fabulous dance. Here, in the alien deep freeze of our Solar System's outer suburbs, the ice dwarf planet Pluto and its quintet of moons dwell along with a cornucopia of others of their bizarre and frozen kind. This very distant region of our Star's domain is so far from our planet that astronomers are only now first beginning to explore it, thanks to the historic visit to the Pluto system by NASA's very successful and productive New Horizons spacecraft on July 14, 2015. New Horizons is now well on its way to discover more and more long-held secrets belonging to this distant, dimly lit domain of icy worldlets.
Cassini is an unmanned spacecraft sent to the Saturn system. It is the fourth space probe to visit the ringed planet, as well as the first to enter orbit. It has been studying Saturn and its many moons since arriving there in 2004.