A liquid ocean is suspected under the ice sheet of Saturn’s moon Enceladus. Researchers are now describing possible traces of life on Saturn’s moon. On the celestial body there are fountains of water vapor that contain methane. Based on an extensive statistical analysis, researchers have now found that microbes are the most likely cause of the methane. At the bottom of the ocean, hidden under a thick layer of ice, there are presumably hot springs with a life-friendly environment. If no life has arisen there, there must be a previously unknown source for the methane, according to the scientists in the journal “Nature Astronomy”.
The Cassini space probe even succeeded in snapping up some water ice in its flyby, which was escaping from these structures known as “tiger stripes”. The analyzes showed that the water is salty and contains organic molecules. This makes the moon a potential extraterrestrial habitat. Just recently, a study provided new evidence that the methane detected in the water vapor fountains could actually come from microbes. An obvious explanation would be that there are hydrothermal vents at the bottom of Enceladus ocean that can produce methane.
On the ocean floor of earth there are ecosystems that feed on the available chemical energy instead of sunlight. Possibly these hot springs also played an important role in the creation of life on earth. In order to clarify whether it could be similar on Enceladus, Antonin Affholder from the Université PSL in Paris and his colleagues analyzed the data collected by Cassini about geophysical, geochemical and biological processes in a complex statistical procedure.
“The observed amount of methane cannot be explained solely by non-biological changes in the rocky subsurface,” is how the researchers summarize the result of this analysis.
Assuming that the origin of life on earth is not an coincidence, one would have to assume that microbes are the most likely source of methane on Enceladus. The researchers estimate that the life-friendly conditions on Saturn’s moon have existed for several billion years, which is “sufficient time for life to develop”.
However, it is also known that life does not inevitably arise under suitable conditions, making it an extremely unlikely and rare event. Still, the data from the Cassini space probe suggests that the conditions at the bottom of the Enceladus ocean are friendly to life.