Methane in the plumes of Saturn's moon Enceladus: Possible signs of life?

[beecee]

https://phys.org/news/2021-07-methane-plumes-saturn-moon-enceladus.html

An unknown methane-producing process is likely at work in the hidden ocean beneath the icy shell of Saturn's moon Enceladus, suggests a new study published in Nature Astronomy by scientists at the University of Arizona and Paris Sciences & Lettres University.

Giant water plumes erupting from Enceladus have long fascinated scientists and the public alike, inspiring research and speculation about the vast ocean that is believed to be sandwiched between the moon's rocky core and its icy shell. Flying through the plumes and sampling their chemical makeup, the Cassini spacecraft detected a relatively high concentration of certain molecules associated with hydrothermal vents on the bottom of Earth's oceans, specifically dihydrogen, methane and carbon dioxide. The amount of methane found in the plumes was particularly unexpected.

more at link.....................................

the paper:

https://www.nature.com/articles/s41550-021-01372-6

Bayesian analysis of Enceladus’s plume data to assess methanogenesis:

Abstract:

Observations from NASA’s Cassini spacecraft established that Saturn’s moon Enceladus has an internal liquid ocean. Analysis of a plume of ocean material ejected into space suggests that alkaline hydrothermal vents are present on Enceladus’s seafloor. On Earth, such deep-sea vents harbour microbial ecosystems rich in methanogenic archaea. Here we use a Bayesian statistical approach to quantify the probability that methanogenesis (biotic methane production) might explain the escape rates of molecular hydrogen and methane in Enceladus’s plume, as measured by Cassini instruments. We find that the observed escape rates (1) cannot be explained solely by the abiotic alteration of the rocky core by serpentinization; (2) are compatible with the hypothesis of habitable conditions for methanogens; and (3) score the highest likelihood under the hypothesis of methanogenesis, assuming that the probability of life emerging is high enough. If the probability of life emerging on Enceladus is low, the Cassini measurements are consistent with habitable yet uninhabited hydrothermal vents and point to unknown sources of methane (for example, primordial methane) awaiting discovery by future missions.

[joigus]

Enceladus has been on the spotlight for quite some time now, as to possibilities of primitive life.

Thanks for the update.

The most exciting aspect for me is the possibility of tidal forces as mechanism of geothermal activity.