A recent study published in Nature indicates that Saturn’s sixth largest moon, Enceladus, may have ongoing oceanic hydrothermal activity, prompting an interest in whether it may be capable of supporting life. Prior to this, hydrothermal vents had never been found outside of Earth’s oceans, where they are speculated to have allowed life to originate.
In 2005 Enceladus was found to have geysers jettisoning material from its southern pole, supplying Saturn’s most outermost ring, the E-ring, with water vapour and ice. Astrophysicists working with NASA’s Cassini spacecraft used mass spectrometry to carry out an analysis of dust nanoparticles caught in the E-ring; most of these stream particles were identified as silicon dioxide.
The team took the composition and limited diameter range of the particles as evidence of thermal reactions happening at over 90oC between the rocky floors and water of Enceladus’s oceans. This heat is thought to be, at least in part, a result of tidal heating caused by the gravitation pull of Saturn and its other moons.
The data collected also placed an estimate on the salinity and pH of the water. These conditions, combined with the presence of chemical components deemed vital to organic compound synthesis such as nitrogen, methane and carbon dioxide, makes Enceladus biologically viable.
Plans for more specialised investigations into Enceladus’ habitability are already being made. Due to the availability of more up-to-date equipment, these missions are expected to be even more informative and may even be able to return samples to Earth for further testing.