The moon Enceladus, photographed by the Cassini NASA spacecraft
The discovery of phosphates in the subterranean ocean of Enceladus makes it habitable, although not necessarily inhabited. This is the first time that phosphorus has been found in oceans outside of Earth.
Enceladus, one of Saturn’s moons, is one of the most promising places in the Solar System to support life outside of Earth. And as of this Wednesday it is even more so: this frigid world is covered by a global ocean under a layer of ice in which scientists have just discovered phosphorus, one of the ingredients they consider critical for it to be habitable. As detailed in an investigation published in the journal Nature, this is the first time that phosphorus has been found in oceans outside of Earth, a discovery that, in addition to allowing progress in the understanding of these oceanic worlds of the Solar System, supports that Enceladus can meet the necessary conditions to host some kind of life.
The discovery was made using data from the Cassini probe, whose mission ended in 2017 by plunging into Saturn’s atmosphere to self-destruct. Scientists continue to analyze the wealth of data he collected during his 13 years exploring the ringed planet and its moons Titan and Enceladus, finding elements that make them candidates for searching for life in the Solar System.
Specifically, the discovery of phosphorus was possible thanks to the analysis of ice particles expelled from the moon’s subterranean ocean through cracks from which a kind of geyser escaped. Previous models had suggested the presence of phosphorus, but it was not clear if this element was found in large amounts. “Previous Cassini measurements had already shown that Enceladus’s subterranean ocean has moderate salinity, adequate pH, a wide variety of organic compounds, and probably deep-ocean hydrothermal systems as an energy source. However, phosphorus it had not yet been detected, although in general, it is considered a critical ingredient for life. Life on Earth cannot exist without phosphorus (it is in DNA or cell membranes, for example)”, Frank explains to EL MUNDO Postberg, Professor of Planetary Sciences at the Institute of Geological Sciences at the Free University of Berlin and leader of the research. “Our finding of phosphorus in the form of soluble phosphates, readily available in the ocean, can be interpreted as the missing piece to make this Saturn moon’s ocean habitable. However, that does not necessarily mean that it is inhabited.”
J. Miguel Mas Hesse, scientist and former director of the Center for Astrobiology (CAB/CSIC-INTA), agrees, who considers that the effective detection of nutrients such as phosphates “is very relevant” and would support that water from this moon is a good ‘ primordial soup’ for the development of life. “The fact that they have found phosphates in the water ejected from Enceladus is very interesting news in order to determine the possibility that life arose there. Phosphorus is a basic element for life (among other things it forms the band in which the DNA bases are anchored), and finding it in abundance indicates that, at least, the necessary nutrients for life are there,” he says. This discovery, he adds, “seems to indicate that the chemistry in the oceans of the icy moons, at least in the case of Enceladus, would be complete and complex enough to support biological processes.” As the Spanish scientist lists, without connection to this study, the icy moons of Jupiter and Saturn constitute a first priority environment for astrobiology for several reasons: they have a large amount of water; the bottom of its oceans is rocky; due to its proximity to Jupiter and Saturn, which causes tidal forces to heat the interior, so they have a source of energy perhaps comparable to hydrothermal vents in the terrestrial oceans; and by the icy crust on the surface
source: https://www.nature.com/articles/s41586-023-05987-9