Key element for life detected in the ocean of Enceladus

June 14 () –

Data from NASA’s Cassini mission indicate phosphorus in the form of phosphates, a key component for life, They originate from the ice-covered ocean of Saturn’s moon Enceladus.

Cassini explored Saturn and its moon and ring system for more than 13 years. But their data continues to be analyzed by scientists.

“In 2020 (published in 2022), we used geochemical models to predict that phosphorus should be abundant in Enceladus’s ocean,” he said. it’s a statement Southwest Research Institute researcher Christopher Glein, a leading expert on extraterrestrial oceanography. He is co-author of a paper in the journal Nature describing this research. “Now, we have found abundant phosphorus in ice plume samples that bubble up from the subterranean ocean.”

The Cassini spacecraft discovered liquid water beneath Enceladus and analyzed samples in a column of ice grains and gases that gush into space from cracks in the moon’s icy surface. Analysis of a class of salt-rich ice grains by Cassini’s Cosmic Dust Analyzer showed the presence of sodium phosphates. The team’s observational results, along with analogous laboratory experiments, suggest that phosphorus is readily available in Enceladus’ ocean in the form of phosphates.

Phosphorus in the form of phosphates is vital to all life on Earth. It is essential for the creation of DNA and RNA, energy-carrying molecules, cell membranes, bones and teeth in people and animals, and even the marine plankton microbiome. Life as we know it is simply not possible without phosphates.

“We found phosphate concentrations at least 100 times higher in the moon’s plume-forming ocean waters than in Earth’s oceans,” Glein said. “Using a model to predict the presence of phosphate is one thing, but finding evidence of phosphate is incredibly exciting. This is an amazing result for astrobiology and a big step forward in the search for life beyond Earth.”

One of the most profound discoveries in planetary science in the last 25 years is that worlds with oceans beneath a surface layer of ice are common in our solar system. Such worlds include the icy satellites of the giant planets, such as Europa, Titan, and Enceladus, as well as more distant bodies such as Pluto.

Worlds like Earth with surface oceans must reside within a narrow range of distances from their host stars to maintain temperatures that support liquid surface water. Inner ocean worlds, however, can occur over a much wider range of distances, greatly expanding the number of habitable worlds likely to exist throughout the galaxy.

“Geochemical experiments and modeling demonstrate that such high phosphate concentrations are the result of increased phosphate mineral solubility on Enceladus and possibly on other icy ocean worlds in the solar system beyond Jupiter,” Glein said. “With this finding, it is now known that Enceladus’ ocean meets what is generally considered the most stringent requirement for life. The next step is clear: we must go back to Enceladus to see if the habitable ocean is actually inhabited.”