For more than a decade one of Saturn’s moons has captured the attention of scientists and, why not say it, the world. This little satellite, called Enceladus, has an ocean under its frozen surface, making it one of the main candidates in the Solar System to host life. Now, a study shows that indeed the Sea of Enceladus has the necessary conditions for microscopic life to develop.
Cassini probe has been studying Saturn and its satellites since 2004 and your mission is about to end. But before doing so, it seems that he wants to give his last blows. Of course, this latest study has returned to focus on Enceladus, the sixth largest moon on that planet and which has captured most of the attention since we learned that it could host an ocean under its icy surface.
The existence of this ocean has been suspected from the beginning of the mission. It was in 2005 when some images taken by Cassini they showed some huge geysers that released steam at the south pole of this satellite. But it took several years until, in 2014, the first tests that demonstrated the presence of this ocean were published.
From then on, speculation began about the possibilities that this ocean could harbor some form of life, despite the fact that the thick layer of ice that covers it prevents light from reaching its interior. So the next step was try to determine the composition of that ocean And, for this, the quickest way was to analyze one of those gas columns that emerged between the cracks in the ice crust.
On this occasion, the scientists used the data collected by the Cassini probe in 2015, when the spacecraft made the deepest dive on the satellite. During this dive the spacecraft headed at a speed of 8.5 kilometers per second towards the south pole of this moon, where data was collected from a large steam column.
Conditions for life
The team of researchers, led by Hunter Waite of the Southwest Research Institute, suspected that these geysers could hydrothermal systems similar to those of our planet and, if this was so, the expelled gases should contain molecular hydrogen. “We have used the mass spectrometer on board the Cassini spacecraft to detect molecular hydrogen in the gas column,” the study authors explain.
The results, which have been published today in the journal Science, not only demonstrate the presence of this compound in the gas columns, but also show that the only plausible source of this hydrogen is, indeed, hydrothermal reactions similar to those that occur on Earth. “We believe that the most plausible source of this hydrogen is hydrothermal reactions that take place in contact with hot rock,” the scientists explain.
According to the researchers, this is of utmost importance, because the detection of molecular hydrogen in the gas column “indicates that the temperatures and sources of chemical energy necessary for the interior of Enceladus to have habitable conditions are being given“. Under these conditions, scientists say, living organisms based on molecular hydrogen can emerge, just like some of the oldest life forms on Earth.
As in the hydrothermal systems of our planet, where water reacts with hot rocks to form columns of various materials, researchers have shown that conditions exist in Enceladus for a process known as metanogénesis, a reaction that facilitates the appearance of microorganisms in the deepest regions of the Earth. According to the authors in the study, “the relatively high abundance of hydrogen measured in the geyser indicates that the thermodynamic processes that favor the formation of methane are taking place.”
The researchers assure that their results support the feasibility of methanogenesis in a wide range of settings possible, although they recognize that only with the thermodynamic data they have at their disposal they cannot guarantee one hundred percent that this process is really happening. In any case, it seems that every time we are closer to find life outside our planet and, what is even more interesting, it may be found in our Solar System.