Could salty ocean lie below Saturn’s moon Enceladus?

William Atkins
Thursday, 25 June 2009 17:36

Science - Space

Linda Spilker, the Cassini deputy project scientist at the Jet Propulsion Laboratory (Pasadena, California), stated, “Potential plume sources on Enceladus are an active area of research with evidence continuing to converge on a possible salt water ocean. Our next opportunity to gather data on Enceladus will come during two flybys in November."

The NASA JPL article continues to state, “The makeup of the outermost ring grains, determined when thousands of high-speed particle hits were registered by Cassini, provides indirect information about the composition of the plume material and what is inside Enceladus. The outermost ring particles are almost pure water ice, but nearly every time the dust analyzer has checked for the composition, it has found at least some sodium within the particles.”

Dr. Postberg concludes, "Our measurements imply that besides table salt, the grains also contain carbonates like soda. Both components are in concentrations that match the predicted composition of an Enceladus ocean.”

A water liquid ocean on Enceladus could likely hold the possibility of life.

Dr. Postberg adds, "The carbonates also provide a slightly alkaline pH value. If the liquid source is an ocean, it could provide a suitable environment on Enceladus for the formation of life precursors when coupled with the heat measured near the moon's south pole and the organic compounds found within the plumes."

However, another paper in the same issue of the journal Nature disputes the observation of salt in the ice grains of the geyser.

They used ground-based observations, but did not observe any sodium, a component of salt. However, they contend that Enceladus could likely have ocean water beneath its surface, only that the geysters do not contain salt, having it evaporate out before they spew it out in the atmosphere.

Sascha  Kemph, a Cassini scientist also from the Max Planck Institute for Nuclear Physics, states, “Finding salt in the plume gives evidence for liquid water below the surface. The lack of detection of sodium vapor in the plume gives hints about what the water reservoir might look like."

Scientists will continue to study Enceladus and the rings of Saturn to determine once and for all if salt is present in the geysers spewing from Enceladus and adding materials to the outermost ring of Saturn.

Their next chance to observe the geysers come in November 2009, when Cassini flies by Enceladus again. Its extended mission now goes into the middle part of 2010.