Prospects of Life on This Moon 'Are Getting Better and Better'

Scientists previously discovered the six essential ingredients of life spewing from Enceladus, one of Saturn's 146 moons, which is considered to have one of the best chances of hosting life of any known planetary body in the solar system besides Earth. Now, they've discovered evidence of a poisonous gas "which—perhaps counter-intuitively—is a sign that the ocean that lies beneath the surface of this icy moon of Saturn could be capable of hosting life," per New Scientist. A reanalysis of data from the Cassini spacecraft, which performed several flybys of Enceladus before its 2017 demise, showed evidence of previously undetected compounds including the poisonous gas hydrogen cyanide, acetylene, propene, ethane, and an alcohol like methanol.

"All of these compounds could be part of chemical reactions that are crucial for life, but hydrogen cyanide is particularly promising," per New Scientist. "It's the starting point for most theories on the origin of life," Jonah Peter, a Harvard biophysics graduate student and co-author of a study on the findings published Thursday in Nature Astronomy, tells the New York Times. "It can be combined in different ways to produce amino acids, which are precursors for proteins as well as nuclear bases and sugars which are needed to make RNA [ribonucleic acid]and DNA [deoxyribonucleic acid]." Peter and colleagues constructed models of 10 to 15 compounds from a list of 50 compounds they thought might be present at Enceladus, then compared the models to what Cassini observed.

"The more we tried to poke holes in our results by testing alternative models, the stronger the evidence became," Peter tells NASA. "Eventually, it became clear that there is no way to match the plume composition without including hydrogen cyanide." The findings "indicate there may be much more chemical energy inside this tiny moon than previously thought," according to NASA. In the words of Frank Postberg, a planetary scientist who led a recent study describing the discovery of phosphorous, one of the essential ingredients of life, on Saturn's moon, the study shows "the prospects for the development of life are getting better and better on Enceladus," per the Times. (More Saturn stories.)