Humanity may not need to look far to find the presence of life “elsewhere in the universe,” said researchers Tuesday. Enceladus, the moon of Saturn, has the ideal living conditions for the presence of unicellular microorganisms.
Along with Europa, the moon of Jupiter, Enceladus is perhaps our best chance to discover one day extraterrestrial life. It shelters a liquid ocean beneath its surface that could actually harbor unicellular microorganisms known as archaeans, found in some of Earth’s most extreme environments, according to a report published this week in the journal Nature Communications. A methanogenic archaean – a methane producer – called Methanothermococcus okinawensis would have flourished in the laboratory under conditions simulating the environment of the icy moon.
On Earth, you will find this type of Archean evolving at very high temperatures near deep hydrothermal vents. They convert carbon dioxide and hydrogen into methane. What we must remember here is that traces of methane were also detected by the Cassini probe in the vapors emanating from the cracks of the Enceladus surface. “We have concluded that some of the CH4 (methane) detected in Enceladus plumes could, in principle, be produced by methanogens,” explain the researchers, noting in passing that enough hydrogen could be produced to support such microbes, in particular by geochemical processes ongoing in the rock nucleus of the moon.
The data collected in the laboratory does not affirm that there is indeed life on Enceladus, but that the conditions seem on the other hand favorable to allow the presence of methanogenic archaeans. “Our study only concerns micro-organisms, I would like to avoid any speculation on intelligent life,” says Simon Rittmann, from the University of Vienna. Concerning Enceladus’ methane, further research will obviously be needed to exclude a geochemical and not a biological origin.