The Cassini-Huygens exploration of Saturn, a seven-year joint venture of NASA, the European Space Agency, and the Italian Space Agency, is realizing more surprising discoveries. The Cassini space probe achieved its closest approach of any Saturn moon with a 109 mile orbit of one of the most innermost moons of Saturn, Enceladus on November 26, 2005.

Enceladus is a small moon of 314 miles across that is so bright it reflects nearly one hundred percent of its heat. For this reason, it is a very cold moon, with a temperature of minus 330 degrees Fahrenheit. Its orbit is influenced under the large gravitational pull of Saturn as well as the gravitational influence of large nearby moons Tethys and Dione. Previous voyages by Voyager as well as Cassini have shown it to have at least five different geological terrains across its small surface.

What was discovered that makes Enceladus so unique for such a cold moon is that unlike nearby moon Mimas, which is basically a completely dead moon, Enceladus is currently geologically active. An emission of water vapor and minute ice particles from its south pole from some sort of internal heat source on Enceladus has been confirmed. The cause of the tremendous heat source that must be present to heat the ice of such a cold moon to emit such a plume of ice and water vapor into the atmosphere is unkown. On its nearest approach to Enceladus of 109 miles, Cassini was able to use infrared detection to prove the existence of this column of ice into the atmosphere and beyond.

Saturn