content long 17-August-2018 18:37:05

Winners Ireland

16-18 years old: Ice plumes at the south pole of Enceladus

Author: Jack Kennedy

I think the icy plumes of Enceladus will yield incredible scientific results. Saturn's largest Moon, Titan was of particular interest to scientists because they thought it was the most able body of harbouring life in our solar system besides Earth. Since then Enceladus has grasped the scientific enthusiasm that Titan once held. In contrast to Titan, Enceladus is a lot smaller, 10.2 times smaller. Although it is small and exerts quite a week gravitational force, scientists believe that it has the greatest potential in the Solar system for harbouring extra-terrestrial life. The 30-kilometer thick ice sheets that cover the surface of Enceladus float on top of an ocean that is likely 10 kilometres deep. This would explain the slight wobble that Enceladus has. It is still hard to determine whether this ocean is a global body of water or just an ocean confined to the south pole of Enceladus. Cryovolcanoes expel large amounts of water vapour travelling at a speed of 0.556 km/s. This is a sufficient speed for the contents of the expulsion to escape Enceladus's gravity as the escape velocity is only 0.239 km/s. The particles are then caught in the gravitational pull of Saturn where they have become the primary contributor to Saturn's E-ring, a much fainter ring compared to the rest. Enceladus's atmosphere is composed of 91% water vapour which may have once been part of the subsurface ocean but was ejected from the cryovolcanoes. When Cassini performed a daring flyby of Enceladus it analysed the particles discharged from the cryovolcanoes and determined that they contained the mineral salt. This further supports the claim of a subsurface salt water ocean. As many of us know liquid water must maintain a temperature of between 0 and 99 degrees celsius in order to maintain it's liquid state. This would require Enceladus to possess a source of heat or have it generated by other means. New evidence, thanks to the Cassini mission, suggests that Enceladus's ocean floor could be at near-boiling temperatures. It would be the first evidence of hydrothermal vents on a solar body other than our home, Earth. This is one plausible theory. However, there is another more likely theory. It is could all be down to what we call tidal heating. Heat can be generated by tidal forces as a result of orbital resonance between Enceladus and another Saturnian moon twice as large called Dione. The heat would be no greater than 1.1 gigawatts. That's enough power to power 750,000 homes. The presence of radioactive material could add an extra 0.3 gigawatts to the total power generated on Enceladus. The possibility of a subsurface ocean being heated to the point of boiling is incredibly fascinating on its own, but maybe there could be life. It may only be microbial but it would be revolutionary. There may even be remnants of past life frozen in the ice waiting to be found. These are questions we hope to answer and can answer with further investigation.

Last Update: 19 May 2017

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