[LINK] The Geysers of Enceladus

[rfmcdonald]

From MSNBC, news that Saturn's moon Enceladus is even more interesting than planetary scientists thought before the arrival of the Cassini in the Saturn system.

Scientists have found evidence that cold, Yellowstone-like geysers of water are issuing from a moon of Saturn called Enceladus, apparently fueled by liquid reservoirs that may lie just tens of yards beneath the moon's icy surface.

The surprising discovery, detailed in Friday's issue of the journal Science, could shoot Enceladus to the top of the list in the search for life elsewhere in our solar system. Scientists described it as the most important discovery in planetary science in a quarter-century.

"I think this is important enough that we will see a redirection in the planetary exploration program," Carolyn Porco, head of the imaging team for the Cassini mission to Saturn, told MSNBC.com. "We've just brought Enceladus up to the forefront as a major target of astrobiological interest."

The readings from Enceladus' geyser plumes indicate that all the prerequisites for life as we know it could exist beneath Enceladus' surface, Porco said.

"Living organisms require liquid water and organic materials, and we know we have both on Enceladus now," she said. "The plumes through which Cassini flew last July contain methane, contain CO2, propane — they contain several organic materials."

The third necessary ingredient — energy for fueling life's processes — could exist around hydrothermal vents around the bottom of Enceladus' water reservoirs, just as it does around Earth's deep-ocean hydrothermal vents.

The results impressed University of Colorado planetary scientist Robert Pappalardo, who has studied Enceladus and other icy moons but was not involved in the newly published research.

"I think the discovery of activity on Enceladus is about the most exciting discovery in planetary science since the volcanoes of Io," he said, referring to the detection of volcanic activity on Jupiter's moon by the Voyager probe in 1979.

With recent suggestions that Titan's methane is produced by outgassing from that planet-sized moon's core, and continuing uncertainty as to whether Titan has a subsurface water ocean like three of the four Galilean moons of Jupiter, this discovery does indeed seem to make Enceladus the most attractive target for exploration in the Saturn system.

A question to the planetary scientists out there: Have scientists determined how Enceladus, substantially smaller than the Galilean moons, is able to keep an ocean of liquid water? I thought that I remembered news reports claiming that there just wasn't enough heating produced by tidal friction--with Saturn, with Titan--to account for this, but I may have misremembered and the reports I did hear a couple of years ago.