NASA Guppy Airplane

However, Dr. Thomas explained to the press in May 2013 that the ring arcs are much more tenuous than the fully formed rings of Saturn. As a matter of fact, the ring arcs are so delicate and thin that it would take about ten billion years for just 1 meter of blowing icy snow to collect within the craters of Methone. The existence of such powerful roaring winds kicking up violent and powerful dust storms suggests that the underlying sand can be set in motion, too, and that the giant dunes covering Titan's equatorial regions are still active and continually changing. 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."