Phosphorus, essential element needed for life, detected in ocean on Saturn's moon
Scientists have discovered phosphorus on Enceladus, the sixth largest moon of Saturn, NASA said Wednesday. The element, which is essential to planetary habitability, had never before been detected in an ocean beyond Earth.
The remarkable discovery, which was published in the journal Nature, is the last piece in the puzzle, making Enceladus' ocean the only one outside of Earth known to contain all six elements needed for life — carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur.
Using data from NASA's Cassini spacecraft, researchers found the phosphorus within salt-rich ice grains that the moon launched into space. The ocean on Enceladus is below its frozen surface and erupts through cracks in the ice.
According to NASA, between 2004 and 2017, scientists found a wide array of minerals and organic compounds in the ice grains of Enceladus using data collected by Cassini, such as sodium, potassium, chlorine and carbonate-containing compounds. Phosphorus is the least abundant of those essential elements needed for biological processes, NASA said.
The element is a fundamental part of DNA and is present in the bones of mammals, cell membranes and ocean-dwelling plankton. Life could not exist without it, NASA says.
"We previously found that Enceladus' ocean is rich in a variety of organic compounds," Frank Potsberg, a planetary scientist at the Freie Universität Berlin who led the latest study, said in a statement. "But now, this new result reveals the clear chemical signature of substantial amounts of phosphorus salts inside icy particles ejected into space by the small moon's plume. It's the first time this essential element has been discovered in an ocean beyond Earth.
While scientists are excited about what this latest find could mean for life beyond Earth, they emphasized that no actual life has been found on Enceladus or anywhere else in the solar system, outside of Earth.
"Having the ingredients is necessary, but they may not be sufficient for an extraterrestrial environment to host life," said Christopher Glein, a co-author and planetary scientist at Southwest Research Institute in San Antonio, in a statement. "Whether life could have originated in Enceladus' ocean remains an open question."
While Cassini is no longer in operation because it burned up in Saturn's atmosphere in 2017, the data it collected continues to reveal new information about life in our solar system, like it has in this latest study.
"Now that we know so many of the ingredients for life are out there, the question becomes: Is there life beyond Earth, perhaps in our own solar system?," said Linda Spilker, Cassini's project scientist at NASA's Jet Propulsion Laboratory in Southern California, who was not involved in this study. "I feel that Cassini's enduring legacy will inspire future missions that might, eventually, answer that very question."
In 2024, NASA plans to launch the Europa mission in order to study potentially similar oceans under the frozen surfaces of Jupiter's moons.