Ruxandra Icleanu

Year: 2018-19

Ruxandra Icleanu

School: “Tudor Vianu” National High School of Computer Science

City: Bucharest

"The chosen target is Saturn’s geysers possessing moon, Enceladus. Explored by the Voyager and Cassini spacecrafts, it started to raise interest after the spectacular findings of the last mission.

One of the unique characteristics of Enceladus is the presence of so-called “tiger stripes”found in the south polar region of the moon. These four 130-kilometres long depressions are considered to be fissures of lithosphere and are the only place on Enceladus where organic materials were detected. Further observations revealed a cryovolcanically active region positioned in the tiger stripes zone: a plume formed of a mixture of water vapor, ice, methane, carbon dioxide, nitrogen, simple and complex organics, along with silica, is emanated continuously from the depressions. These eruptions create a fine-grained ice dust around Enceladus, forming Saturn’s E-ring, but a considerable fraction of this icy particles fall back. The ice coating on its surface makes Enceladus one of the most reflective bodies in the Solar System. An inevitable question quickly appeared: where is the water coming from? To discover that an underground liquid ocean is hidden under the icy crust was the truly promising discovery which leads us to the question: could life on Enceladus be possible?

Another reason that makes this icy moon so scientifically interesting is the internal heat. The temperature measured at its equator, the place that receives the most sunlight, is -316 °F. It would be expected that any other region has lower temperatures, but it was revealed that the tiger stripes region is on average 70°F hotter than the equator, with places that reach -135 °F. Previously, it was thought that the internal heat is mostly generated by tidal forces that appear between Enceladus and another Saturn’s moon, Dione. The expected value was calculated at approximately 1.5 gigawatts, while the measured value was, surprisingly, 15.8.

Moreover, there have been published results that confirm the existence of complex macromolecular organic materials, with molecular masses above 200 atomic mass units, compared to the ones previously found which are below 40 atomic mass units.

These astounding features of Enceladus encourage us to explore deeper in order to find a response to the problem of finding a habitable planet. Another mission would be necessary to get a better view of the facilities the moon dispose of. One of the problems that should be solved is to find if there is geothermal heating by hydrothermal vents and what forms of life are possible in those conditions. Another question is caused by the presence of pure 2 to 8 nanometers silica crystals, which are known to be formed only if they are exposed to very high temperatures, of nearly 200 °F - so what is the highest temperature that Saturn’s moon can reach?

All in all, taking into consideration its undersurface liquid ocean, the presence of complex organic molecules and the yet-unexplained internal heat, Enceladus represents a fascinating world that reveals more and more evidence it is capable of sustaining life in any form, human or not."

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