This story sounds a little similar to one we covered last year, up to and including the media hype. Phosphine on Venus! Signs of life! Only this time, the gas is methane and the planet is a moon – Saturn’s moon Enceladus, to be specific. 

In new work published in Nature Astronomy, researchers used mathematical models to try to understand the reason for the large amount of methane found in the plumes of Enceladus by the Cassini spacecraft. These models combined geochemistry and microbial ecology, looking at the amounts of dihydrogen, methane, and carbon dioxide in the plumes. As co-author Regis Ferriere explained: We wanted to know: Could Earthlike microbes that ‘eat’ the dihydrogen and produce methane explain the surprisingly large amount of methane detected by Cassini? Searching for such microbes, known as methanogens, at Enceladus’ seafloor would require extremely challenging deep-dive missions that are not in sight for several decades.

The team tested a variety of different models to assess just how much methane could be produced depending on the conditions, including hydrothermal production of dihydrogen, possible population dynamics, and temperature. The results don’t say there is life. What they do say is that the amount of methane could be explained by biological processes but more data is required to know for certain. Basically, it could be life, but to find out if it is life, well, we need to go there and get a sample.

More Information

University of Arizona press release

Methane mystery on Saturn’s icy moon Enceladus: Could it be a sign of life? (CNET)

“Bayesian analysis of Enceladus’s plume data to assess methanogenesis,” Antonin Affholder et al., 2021 June 7, Nature Astronomy