Geological activity on Saturn's moons

Stephen Withers
Thursday, 14 June 2007 04:49

Science - Space

Data from the Cassini mission suggests another two of Saturn's moons may be geologically active.

An analysis of data from the Cassini Plasma Spectrometer performed by Jim Burch of the Southwest Research Institute and other researchers shows plasma is being ejected from Tethys and Dione, two of Saturn's moons that orbit beyond the planet's famous rings.

The emission of plasma is associated with geological (possibly volcanic) activity. Enceladus was the only one of the inner Saturnian moons already known to be active, with previous Cassini observations revealing geysers ejecting gases hundreds of kilometres above the moon's surface.

“This new result seems to be a strong indication that there is activity on Tethys and Dione as well,” says Burch's collaborator Andrew Coates of the Mullard Space Science Laboratory, University College London.

Activity means a planet or moon has not yet reach equilibrium or that it is being supplied with energy.

More fly-bys of Tethys and Dione are scheduled to provide close ups of the moons.