Methane in the Plumes of Saturn's Moon Enceladus: Possible Signs of Life

Science time:

Even though this site is mostly for political science, at times I feel the need to observe scientific events. This article looks at the possibility that we may not be alone in the universe. Any life from this moon  will not be intelligent and probably very primitive. But it would show that we are not alone in the Universe.

-Steve Otto

From News Univercity of  Arizona:

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.

"We wanted to know: Could Earthlike microbes that 'eat' the dihydrogen and produce methane explain the surprisingly large amount of methane detected by Cassini?" said Régis Ferrière, an associate professor in the University of Arizona Department of Ecology and Evolutionary Biology and one of the study's two lead authors. "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."

Ferrière and his team took a different, easier route: They constructed mathematical models to calculate the probability that different processes, including biological methanogenesis, might explain the Cassini data.

The authors applied new mathematical models that combine geochemistry and microbial ecology to analyze Cassini plume data and model the possible processes that would best explain the observations. They conclude that Cassini's data are consistent either with microbial hydrothermal vent activity, or with processes that don't involve life forms but are different from the ones known to occur on Earth.

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This cutaway view of Saturn's moon Enceladus is an artist's rendering that depicts possible hydrothermal activity that may be taking place on and under the seafloor of the moon's subsurface ocean, based on results from NASA's Cassini mission.NASA/JPL-Caltech