Is Enceladus habitable?

- Cassini found **molecular hydrogen (H₂)** in the south-polar plumes — a hallmark of water–rock reactions like those that power Earth’s hydrothermal-vent ecosystems. - Cassini also detected **nanograins of silica**, best explained by hot (>90 °C) water circulating through rock at the seafloor. - Most strikingly, reanalysis of Cassini dust data revealed **sodium phosphates** — direct evidence that **bio-essential phosphorus** is available in Enceladus’s ocean, likely at concentrations ≳100× those of Earth’s oceans. - Together with abundant organics and a salty global ocean, Enceladus checks many boxes for potential habitability.

# Sources - Cassini detections of phosphates, silica nanograins, and H₂ (Nature 2023; Nature 2015; *Science* 2017) - nature and science - European Space Agency’s Enceladus priority under Voyage 2050 (ESA) - esa.int