Planetary Science: Looking below the surface of Enceladus

The core of Enceladus, one of Saturn’s moons, is thought to be similar to that of primitive meteorites, according to experiments presented in Nature Communications this week. The southern hemisphere of this moon is geologically active and, based on the observed hydrothermal activity, it has been possible to model the conditions beneath the crust.

The recent detection of plumes of ice and silica-rich particles originating inside Enceladus’ icy crust has suggested that water-rock interactions are currently occurring deep inside the moon. In order to simulate the generation of the tiny silica-rich particles, Yasuhito Sekine and colleagues experimented with gases similar in composition to those in the observed plumes. In the laboratory, they were able to create liquids at the conditions found on Enceladus and suggest that they are consistent with the formation of serpentine and saponite, minerals also found in primitive meteorites. If the core of Enceladus has this primitive composition, it is likely that the moon formed very early in Solar System history. The reaction conditions also suggest that hydrogen production is taking place, which could provide energy for possible life forms beneath the surface.

NASA’s Cassini mission around Saturn will begin its ‘Grand Finale’ phase late next year , conducting some of its most daring manoeuvres before it runs out of fuel in 2017. The final flybys of Enceladus, including a dive through the water-rich plumes from the active geysers, will take place late October and December 2015 and may help corroborate the current study.

doi: 10.1038/ncomms9604

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