Enceladus, the icy moon of Saturn, meets the basic requirements for life as we know it, according to scientists who have identified large organic molecules rich in carbon that come out of cracks on its surface. Their study was published in the magazine Nature
“We must be cautious, but it is exciting to consider that this discovery indicates that the biological synthesis of organic molecules is possible in Enceladus,” one of the co-authors of the Christopher Glein article explained in a statement.
Scientists at the American Southwest Research Institute (SwRI) believe that the chemical reactions between the rocky core of Enceladus and the warm water of the ocean in its subsoil are linked to the existence of these complex molecules.
The search for life possibilities beyond Earth has focused on some of our neighbors in the Solar System and scientists believe that the best chances could be Europa, one of the moons of Jupiter, and Enceladus, which orbits Saturn.
“Enceladus surprises us once again, we had previously identified only the simplest organic molecules, a few carbon atoms, but even that was very enigmatic,” said Glein, who specializes in extraterrestrial chemical oceanography at SwRI.
Now, he added, scientists have located these molecules with masses greater than 200 units of atomic mass, ten times heavier than methane.
With these complex organic molecules emanating from its ocean of liquid water, Enceladus is the only separate body other than Earth to “simultaneously satisfy all the basic requirements for life as we know it,” the expert explained.
The Cassini probe disintegrated last September in the atmosphere of Saturn, after a mission of 20 years collecting data from that planet and its moons, and during its flight, it recorded a column (plume) of matter that emerged from the underground of Enceladus.
The astronomers used the cosmic dust analyzer (CDA) and the neutral mass ion spectrometer (INMS) on board Cassini to make measurements of both the plume and Saturn’s E-ring, which is made up of the grains of ice that escape the gravity of Enceladus.
Cassini flew over Saturn’s sixth largest moon in 2015, when the INMS detected molecular hydrogen as it passed through the plume. Experts believe that this compound is formed by the geochemical interaction between water and rocks in hydrothermal environments.
Hydrogen provides a chemical energy source that “helps bateria that live in Earth’s oceans near hydrothermal vents,” explained study principal investigator Hunter Waite of SwRI.
Waite said that “once a potential source of food for bacteria has been identified, the next question to ask is: What is the nature of the complex organic compounds in the ocean? This study represents the first step towards that knowledge.”
Even after its mission came to an end, the Cassini probe “continues to give us data on Enceladus’ potential to advance in the field of astrobiology in an oceanic world,” Glein added.
The results of this study have, according to Glein, “a great importance” for other explorations, since a future space probe could fly through a column of Enceladus and analyze those complex organic molecules using a high-resolution mass spectrometer that could help analyze how they are made.