Medium Earth Orbit



Titan has three large seas. However, the seas of Titan are not filled with water, but are filled instead with swirling liquid hydrocarbons. All three of Titan's exotic seas are close to its north pole, and they are surrounded by many smaller hydrocarbon-filled lakes in the northern hemisphere. Simply put, resistance to the creation of a space frontier originates with the insecurities of Western leaders. First, it is clear that everything changes with the emergence of a frontier. Established power structures are usually shaken, not reinforced. (If this is not clear, try reading Walter Prescott Webb's The Great Frontier, particularly the last chapter, and Divided We Stand: The Crisis of a Frontierless Democracy, by the same author.) 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."