[ExI] Enceladus

[Stuart LaForge]

Last week was a pretty exciting week for astrobiologists because NASA
reported in the journal Nature that the Cassini space probe found complex
organic molecules in the geyser plumes of Saturn's ice-moon Enceladus.
Specifically the article mentions pyrenes which are multiple aromatic
carbon rings bonded together.

If Enceladus has sufficient tidally induced volcanism to harbor volcanic
vents and liquid water beneath the ice, an entire ecosystem of
extremophiles could thrive down there!

https://www.jpl.nasa.gov/news/news.php?feature=7174
https://www.nature.com/articles/s41586-018-0246-4

Abstract:
Saturn’s moon Enceladus harbours a global water ocean1, which lies under
an ice crust and above a rocky core2. Through warm cracks in the crust3 a
cryo-volcanic plume ejects ice grains and vapour into space4,5,6,7 that
contain materials originating from the ocean8,9. Hydrothermal activity is
suspected to occur deep inside the porous core10,11,12, powered by tidal
dissipation13. So far, only simple organic compounds with molecular masses
mostly below 50 atomic mass units have been observed in plume
material6,14,15. Here we report observations of emitted ice grains
containing concentrated and complex macromolecular organic material with
molecular masses above 200 atomic mass units. The data constrain the
macromolecular structure of organics detected in the ice grains and
suggest the presence of a thin organic-rich film on top of the oceanic
water table, where organic nucleation cores generated by the bursting of
bubbles allow the probing of Enceladus’ organic inventory in enhanced
concentrations.

Stuart LaForge