Phosphorus has not previously been detected in oceans beyond those on Earth and this discovery provides a promising step forward in our understanding of ocean worlds.
Enceladus, the sixth-biggest moon of Saturn, harbors a global water ocean.
This ocean lies under an ice crust and above a rocky core where tidal dissipation is suspected to drive hydrothermal activity.
There are several lines of evidence describing how volatile and dissolved materials from the rocky core are either emitted by the plume in the gas phase or incorporated into ice particles, respectively.
“We previously found that Enceladus’ ocean is rich in a variety of organic compounds,” said Dr. Frank Postberg, a planetary scientist at Freie Universität Berlin.
“But now, our 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.”
Phosphorus in the form of phosphates is vital for 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 sea’s microbiome of plankton.
Life as we know it is simply not possible without phosphates.
“In 2020, we used geochemical modeling to predict that phosphorus should be abundant in Enceladus’ ocean,” said Southwest Research Institute’s Dr. Christopher Glein.
“Now, we have found abundant phosphorus in plume ice samples spraying out of the subsurface ocean.”
In their study, Dr. Postberg, Dr. Glein and their colleagues analyzed mass spectra of E-ring’s ice grains emitted by Enceladus.
The data were collected by the Cosmic Dust Analyzer instrument onboard NASA’s Cassini spacecraft.
The measurements not only detected phosphorus — in the form of orthophosphate ions — but together with laboratory data suggest that phosphorus might be…
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