Jumat, 01 Oktober 2010

The Mystery Behind Saturn's Moon Enceladus

The Cassini-Huygens exploration of Saturn, a seven-year joint venture of NASA, the European Space Agency, and the Italian Space Agency, is getting a closer look at its current subject of attention, the small moon of Enceladus. Enceladus is one of the most innermost moons of Saturn which scientists had assumed to be largely dead. With a very bright surface it reflects nearly 100 per cent of its heat and thereby has a very cold temperature, minus 330 degrees Fahrenheit. A surprising discovery was that Enceladus, unlike nearby similar moon Mimas, is geologically active due to the emission of ice particles propelled by water vapor into the atmosphere from its south pole. Enceladus is a small moon of approximately 300 miles radius and the existence of any geological activity for a moon that size has scientists pleasantly baffled. Discovery of geological activity on any moon has been a rare phenomenon so far. The wonderful unexplained mystery behind Enceladus is the cause of the tremendous heat source that is warming the ice. Scientists can only guess that it is due to tidal activity or radioactive mechanisms for now. At one time it was believed that the heat was being emitted from the mid-latitude tectonic gashes that circumscribe the south polar region. This was what Cassini's approach in July seemed to imply. However in contrast to that orbit of 286 miles, Cassini's more recent closer approach of 109 miles confirmed that the heat was actually being emitted from what are known as the tiger stripes of Cassini. The tiger stripes of Cassini are 80 mile long fissures running parallel to each other spaced about 25 miles apart. Cassini is only 314 miles across. The hottest spots were found in the south polar region of the tiger stripes. Cassini determined there were two types of ice on Enceladus. An older amorphous variety was due to the constant characteristic of the surface of the planet. However the ice particles vented through the tiger stripe fissure were fine crystalline particles. This ice averaged ten microns in size. It is these tiny ice particles escaping the moon's atmosphere that are making up the composition of Saturn's broadest ring, the E ring. In March of 2008, Cassini is scheduled to visit Enceladus again. Perhaps then more light will be shed on the mystery behind Enceladus. 1) Enceladus Erupting – A Nasa Report – 12-7-05 2) Enceladus Plume – Jet Propulsion Laboratory – 12-6-05 3) Possible Source of E Ring – Bill Arnett – 2-17-05 4) Saturn: Moons: Enceladus – Nasa: Solar Systems Exploration – 10-6-03 5) Enceladus's Tiger Stripes are Really Cubs – Nasa Release

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