SpaceRef.com - 2010 Feb 08
In recent dives through the water ice plume of Enceladus, the Cassini plasma spectrometer has found unexpected populations of charged molecules and dust that strengthen arguments for the presence of liquid water and the ingredients for life inside the icy moon.
The Cassini plasma spectrometer, originally designed to take data in Saturn's magnetic environment, measures the density, flow velocity and temperature of ions and electrons that enter the instrument. But since the discovery of Enceladus' water ice plume, the instrument has also successfully captured and analyzed samples of material in the jets.
Early in its mission, Cassini discovered the plume that fountains water vapor and ice particles above Enceladus. Since then, scientists have found that these water products dominate Saturn's magnetic environment and create Saturn's huge E ring.
Now, Cassini scientists report they have found negatively charged ions in the plume, many of which are water, but also including other hydrocarbon species. Their findings, based on analysis from data taken in plume fly-throughs in 2008, are reported in the journal Icarus.