Scientists detect new organics in ice from Saturn’s moon Enceladus

By Busra Nur Cakmak

Scientists have identified new organic compounds in ice grains ejected from Saturn’s moon Enceladus, according to a study published Wednesday in the journal Nature Astronomy.

The findings add to growing evidence that the icy moon may harbor conditions suitable for life.

The discovery comes from a reanalysis of data collected by NASA’s Cassini spacecraft, which in 2008 flew through plumes venting from fractures near Enceladus’s south pole. The ice grains struck the spacecraft at nearly 18 kilometers per second, shattering into fragments that revealed their chemical makeup.

According to the study, researchers detected esters, alkenes, ethers and nitrogen- and oxygen-bearing compounds in the freshly ejected grains, alongside previously reported aromatic and oxygen-containing molecules. The results indicate that Enceladus’s subsurface ocean is chemically diverse, with pathways similar to hydrothermal reactions found on Earth’s ocean floor.

Cassini had earlier identified salts, methane and phosphates in the plume material, meaning five of the six “CHNOPS” elements - carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur - have now been confirmed.

“While the majority of previous results were inferred from relatively old E-ring ice grains, fly-bys of Enceladus by Cassini provided a unique opportunity to sample freshly ejected grains,” the study said.

“This offers compositional insights into ice grains immediately after ejection and ensures that the compounds detected arise from the Enceladean subsurface rather than space weathering in Saturn’s E ring,” it added.

Enceladus, about 310 miles (500 km) across, is covered in bright ice but hides a global salty ocean beneath its crust. Its geysers, blasting material into space, provided a rare natural sampling opportunity for Cassini.