Saturn's Icy Moon Shows Increasing 'Potential for Life,' Study Claims

Saturn's icy moon made headlines after the joint NASA/ESA/ASI Cassini mission first carried out close flybys in 2005. The Cassini spacecraft orbited Saturn for over a decade, offering remarkable insights, with subsequent analysis of data making Enceladus one of the most fascinating worlds in our solar system for astrobiologists.

Yet another startling discovery has been made about Saturn’s intriguing moon Enceladus in the relentless search for habitable worlds beyond Earth.

Previous studies enabled by NASA’s Cassini mission, which ended in 2017, revealed this modest-sized moon’s subsurface ocean is likely the most habitable place in the outer solar system. Now, hydrogen cyanide may be one of the most important compounds discovered in the plumes of vapor and ice shooting from fractures near the moon’s south pole.

Jonah Peter, a biophysics graduate student at Harvard, and his collaborators, Tom Nordheim and Kevin Hand of NASA’s Jet Propulsion Laboratory in California, reported their findings in a paper published in the journal Nature Astronomy. According to the team, they were analyzing data gathered by Cassini's flybys of Saturn from 2004 to 2017, specifically, one of its instruments - the Ion and Neutral Mass Spectrometer (INMS). What the researchers did was write up a list of 50 compounds they suspected might be found on Enceladus. They proceeded to construct models of compounds, and compare the data, drawing the conclusion that among the spray of molecules emanating from the moon was hydrogen cyanide.

“It’s the starting point for most theories on the origin of life,” study lead author Jonah Peter was cited as saying, adding:

“Searching for compounds in the plume is a bit like putting the pieces of a puzzle back together in that we look for the right combination of molecules that reproduce the observed data. Information theory allows us to determine how much detail we can extract from the data without missing important features or overfitting to statistical noise.”

And that is not all, as the study discovered the possible presence of additional compounds and molecules, such as acetylene, ethane, methanol, propylene, and molecular oxygen. The team also potentially detected sulfur and phosphorus - all important elements for life on Earth.

In previous studies, water, ammonia, carbon dioxide, and methane had previously been found in analyses of Cassini data. Enceladus has a salty "soda ocean" beneath a thick layer of ice, with the particles from it migrating through cracks in the ice and spewing jets, or plumes.

"We now really have found that Enceladus’s subsurface ocean is the most habitable place in the solar system, at least as far as we know," lead author of an earlier study, Frank Postberg, wrote in June.

Together, all these discoveries hint that Enceladus could harbor an environment favorable to life within its ocean. While subsequent laboratory experiments could help find out whether these discovered elements and compounds could form "building blocks of life," constructing a robotic mission might be the next step towards studying Enceladus, Peter added.