Saturn’s moon Enceladus has long been one of the most compelling worlds in the solar system for scientists to study. Underneath its icy shell lies a salty liquid ocean that researchers think is a bonafide chemical lab that houses the ingredients needed for biological life to form and thrive.
Much of this, of course, has been wishful thinking. Sure, there have been detections of carbon, hydrogen, nitrogen, oxygen, and sulfur—five of the six essential ingredients needed for life. The presence of powerful plumes stretching hundreds of miles in altitude indicated that there was enough activity brewing under the surface that could churn those elements into something more complex.
However, we were still missing one very important component essential to life: phosphorus, which is often thought to be the rarest of the six.
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That’s all changed now, thanks to a new study published in Nature on Wednesday that indicates the detection of phosphorus on Enceladus, in the form of phosphates. Thanks to a new analysis of data from NASA’s Cassini space mission several years ago, a group of researchers have just found phosphates housed in ice particles that had been ejected into space by the moon’s cryovolcanic plumes (themselves a result of a vents in the ice stretching down to the subsurface liquid ocean.
“Previous geochemical models were divided on the question of whether Enceladus’ ocean contains significant quantities of phosphates,” Frank Postberg, a planetary scientist at Freie Universitat Berlin who led the new study, told The Daily Beast. “However, our Cassini-[Cosmic Dust Analyzer] measurements leave no doubt that substantial quantities of this essential substance are present in the ocean water.
“We did not look for phosphates in particular,” he added, “[but] it was a serendipitous find.”
Phosphorus is an essential part of nucleic acids like DNA and RNA—the structures that make up the genetic code for all life as we know it. Its presence on Enceladus means it could be possible to run chemical reactions that lead to the creation of DNA and RNA, cell membranes, compounds essential for energy and metabolism, and other biochemistry. “Life as we know it would simply not exist without phosphates,” said Postberg.
The Cassini mission ended in 2017 when the spacecraft made a spectacular suicide dive into Saturn’s skies. But data from the mission, which studied Saturn and its moon from 2004 to 2017, is still being processed and analyzed to this day. Postberg and his team have spent the last several years running new investigations on the ice grains recorded by the probe’s Cosmic Dust Analyzer (CDA).
Postberg is the first to say the detection of phosphorus on Enceladus is not entirely surprising, since the element has been found in other parts of the outer solar system and from meteorites originating from that region. But the results are a clear indication that phosphates have been dissolved in Enceladus’ ocean, and “are readily available for the formation of potential life.”
That doesn’t mean the new study is anything close to confirmation that life exists on Enceladus, or even that it truly could. Data from Cassini, a spacecraft that was built decades ago, can only tell us so much.
What the new results may do, however, is generate renewed pressure to greenlight a mission to Enceladus. NASA is already forming plans to one day send a probe to Enceladus and look for signs of life on the surface of the moon—or in its orbit. None of those proposed missions are official, and in the best case scenarios they probably wouldn’t get to Enceladus until the 2030s.
“I guess it will take another 20 years or so until we get the next space probe arriving at Enceladus,” said Postberg. But he’s nevertheless optimistic it will happen. “In my view, it is just a matter of time until such a mission will be implemented.”
