The existence of ample amounts of hydrogen in the subsurface ocean of Enceladus indicates that microbes--if any exist there--could use it to obtain energy by mixing with carbon dioxide dissolved in water. This particular chemical reaction, termed methanogenesis, because it manufactures methane as a byproduct, may have been of critical importance in the emergence of life on our planet.
Therefore, the results of the new study support the idea that primitive life could potentially have evolved on Ganymede. This is because places where water and rock interact are important for the development of life. For example, some theories suggest that life arose on our planet within hot, bubbling seafloor vents. Before the new study, Ganymede's rocky seafloor was believed to be coated with ice--not liquid. This would have presented a problem for the evolution of living tidbits. The "Dagwood sandwich" findings, however, indicate something else entirely--the first layer on top of Ganymede's rocky core might be made up of precious, life-sustaining salty water.
Titan: Titan, the tormented, hydrocarbon-slashed largest moon of Saturn--and the second largest moon in our Solar System, after Ganymede--could possess a subsurface, salty ocean that may well be as salty as the Dead Sea on Earth. The salty water could begin approximately 31 to 62 miles beneath Titan's icy shell, according to recent estimates. Meanwhile, on Titan's smog enshrouded surface, "life as we do not know it" could swim in alien lakes and rivers that flow with liquid methane and ethane hydrocarbons--instead of water.