Saturn's bizarre moon Enceladus is a little more mysterious after the recent Cassini flyby found it to be remarkably like a comet in its internal chemistry.

"A completely unexpected surprise is that the chemistry of Enceladus, what's coming out from inside, resembles that of a comet," says Hunter Waite of the Southwest Research Institute, principal investigator for the Cassini Ion and Neutral Mass Spectrometer. "To have primordial material coming out from inside a Saturn moon raises many questions on the formation of the Saturn system."

The March 12 flyby found the so-called "tiger stripes" around the moon's south pole are some 200 deg. F. warmer than the rest of the moon (although still a frigid -135 deg. F.). The tiger stripes - essentially fissures in the frozen surface - are the source of the spectacular geysers of water and ice that spew so far into space that they actually feed the nearby E-ring around Saturn.

When Cassini flew through the geysers at an altitude of 120 miles on its most recent pass, Waite's spectrometer found them a rich mix of volatile gases, water vapor, carbon dioxide and monoxide and organic materials. Overall, the geysers were about 20 times denser than expected.

That, and the unexpectedly high temperatures associated with the geysers, support speculation that they originate in a subsurface sea of liquid water.

"Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life," says Cassini Project Scientist Dennis Matson of NASA's Jet Propulsion Laboratory. "We have quite a recipe for life on our hands, but we have yet to find the final ingredient, liquid water, but Enceladus is only whetting our appetites for more."

Cassini is scheduled to make another close flyby of Enceladus in August as it continues its unprecedented tour of the Saturn system.