Enceladus is one of the main targets for the search for extraterrestrial life in our solar system. But does it really have all the necessary ingredients? A team of scientists has discovered new evidence of the presence of a key element in the subterranean ocean of this moon.
Enceladus, one of Saturn’s many moons, quickly went from being a small and insignificant object (only 500 kilometers in diameter) to a potential breeding ground for a extraterrestrial life. And for good reason, we know from the Cassini spacecraft that jets of steam emanate from its bowels, suggesting the presence of a global ocean sandwiched between its rocky core and icy shell. But that is not all.
Only five elements are essential for all living things on Earth: hydrogen, oxygen, carbon, nitrogen, and phosphorus. The fact thatEnceladus has an ocean of liquid water. allows us to ensure the presence of the first two elements of the list, and in abundance. Ammonia and methane ices in the moon’s plumes, analyzed by the Cassini spacecraft a few years ago, also confirmed the presence of nitrogen and carbon in Enceladus’ inner ocean.
Until now, however, there were still doubts about the presence of phosphorus. Although other life paths may exist, without phosphorus the prospects for self-replicating organisms would be greatly dimmed. A recent study published in the Proceedings of the National Academy of Sciences ultimately supports the presence of this element.
To detect the presence of phosphorus, Christopher Glein’s team at the Southwest Research Institute took a roundabout route.
We know from its density that the moon harbors a solid core, which almost certainly contains every abundant element in the universe, including phosphorus. In this study, the researchers modeled the interactions between this core and the ocean above to determine whether or not phosphate minerals in the rocks would be released.
As a result, the researchers determined that temperature, pressure, and acidity were ultimately sufficient to make phosphates particularly soluble, primarily in the orthophosphate (PO 4 3−) form. ” The underlying geochemistry has an elegant simplicity that makes the presence of dissolved phosphorus unavoidable, reaching levels close to or even higher than those of Earth’s seawater modern“, confirm the authors.
This does not necessarily mean that Enceladus is inhabited, but it does confirm that it is probably habitable. The only way to be sure would be to go directly to the site to sample more material that is gushing up from the depths. Hopefully, we might find some microbes inside.