The subsurface oceans of Saturn’s moons are likely rich in phosphorus, a key element for life

The search for extraterrestrial life has become more interesting as a team of scientists, including Dr. Christopher Glein of the Southwest Research Institute, has discovered new evidence of a key element of life in the subsurface ocean of Earth’s moon Enceladus.Saturn. New modeling indicates that Enceladus’ ocean should be relatively rich in dissolved phosphorus, an essential ingredient for life.

“Enceladus is one of the main targets of humanity’s search for life in our solar system,” said Glein, a leading expert in extraterrestrial oceanography. He is co-author of an article in Proceedings of the National Academy of Sciences (PNAS) that describes this research. “In the years since NASA’s Cassini spacecraft visited the Saturn system, we have been repeatedly blown away by the discoveries made possible by the data collected. »

The Cassini spacecraft detected liquid water underground at Enceladus and analyzed samples as plumes of ice grains and water vapor erupted into space from cracks in the moon’s icy surface.

“What we’ve learned is that the tab contains almost all of the basic requirements for life as we know it,” Glein said. “While the bioessential element phosphorus has not yet been directly identified, our team has uncovered evidence of its availability in the ocean beneath the moon’s icy crust.”

One of the most profound discoveries in planetary science over the past 25 years is that worlds with oceans beneath a layer of surface ice are common in our solar system. These worlds include the icy satellites of giant planets such as Europa, Titan and Enceladus, as well as more distant bodies such as Pluto. Earth-like worlds with surface oceans must lie within a narrow range of distances from their host stars to maintain temperatures that support liquid surface water. However, inner ocean worlds can occur over a much wider range of distances, greatly increasing the number of habitable worlds likely to exist across the galaxy.

“The search for extraterrestrial habitability in the solar system has shifted focus as we now seek the building blocks of life, including organic molecules, ammonia, sulfur compounds, and the chemical energy needed to support life,” Glein said. “Phosphorus presents an interesting case because previous work suggested that it may be scarce in the Enceladus ocean, which would dim the prospects for life.”

Phosphorus in the form of phosphates is essential for all life on Earth. It is essential for the creation of DNA and RNA, energy-carrying molecules, cell membranes, bones and teeth in humans and animals, and even the marine microbiome of plankton.

Team members performed thermodynamic and kinetic modeling that simulates phosphorus geochemistry based on Cassini’s information about the ocean-ocean floor system on Enceladus. During their research, they developed the most detailed geochemical model yet of how seafloor minerals dissolve in the ocean of Enceladus and predicted that phosphate minerals would be unusually soluble there.

“The underlying geochemistry has an elegant simplicity that makes the presence of dissolved phosphorus inevitable, reaching levels close to or even higher than those of modern Earth’s seawater,” Glein said. “What this means for astrobiology is that we can be more certain than before that the ocean of Enceladus is habitable. »

According to Glein, the next step is clear: “We need to go back to Enceladus to see if a habitable ocean is actually inhabited. »

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Materials provided by Southwest Research Institute. Note: Content can be edited for style and length.

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