But for now Cassini's next step is to pass through the geyser's plume, an encounter scheduled for March 2008.
Matson discussed his research at the annual Lunar and Planetary Science Conference. His findings will appear in the April issue of the journal Icarus.
Moon Had Hot Start
Scientists agree that Enceladus's jets indicate the moon's interior is hot, but how hot and why remain mysterious.
A theory unveiled at the conference suggests that the heat might have originated from the radioactive decay of aluminum and iron.
"Enceladus is a very small body, and it's made almost entirely of ice and rock," said Julie Castillo of JPL in a press release.
"The puzzle is how the moon developed a warm core."
The new theory posits that heat from the decay of radioactive elements softened the moon's interior. This allowed the pull of Saturn's gravity to flex the moon's hot core like a rubber ball—a process that could continue generating heat indefinitely.
Other scientists aren't convinced that radioactive materials were the source of the moon's internal heat.
"There are quite a lot of ideas being kicked around," said John Spencer of the Southwest Research Institute. "This is just one."
"[But] something had to kick-start Enceladus into [its present] state," he added.
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