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Organic chemicals detected at Saturn moon

March 26, 2008
Courtesy NASA
and World Science staff

NASA’s Cas­si­ni space­craft de­tected a sur­pris­ing or­gan­ic “brew” erupt­ing like a gey­ser from Sat­urn’s moon En­cel­a­dus dur­ing a close fly­by on March 12, re­search­ers say.

Sci­en­tists think the moon may al­so have liq­uid wa­ter, which along with the or­gan­ic chem­i­cals and oth­er fea­tures al­ready found could pro­vide most of the pre­req­ui­sites for life.

Geyser-like jets emerge from En­cela­dus in this Cas­sini snap­shot. (Cour­tesy NA­SA)

NASA’s Cassini spacecraft detected a surprising organic “brew” erupting like a geyser from Saturn’s moon Enceladus during a close flyby on March 12, researchers say. Scientists think the moon may also have liquid water, which along with the organic chemicals and other features already found could provide most of the prerequisites for life. Investigators in the Cassini mission described themselves as amazed that this tiny moon is so active, “hot” and brimming with water vapor and organics. New heat maps of the surface show higher temperatures than previously known in the south polar region, with hot tracks running the length of giant fissures. Additionally, scientists say the organics “taste and smell” like some of those in comets. A big surprise “is that the chemistry of Enceladus, what’s coming out from inside, resembles that of a comet,” said Cassini team member Hunter Waite of the Southwest Research Institute in San Antonio, Texas. “To have primordial material coming out from inside a Saturn moon raises many questions on the formation of the Saturn system.” “Enceladus is by no means a comet,” he added. Its activity “is powered by internal heat while comet activity is powered by sunlight. Enceladus’ brew is like carbonated water with an essence of natural gas.” The Cassini instrument for which Waite is principal investigator, the Ion and Neutral Mass Spectrometer, saw a much higher density of volatile gases, water vapor, carbon dioxide and carbon monoxide, as well as organic materials, some 20 times denser than expected. This dramatic increase in density was evident as the spacecraft flew over the area of the plumes. New heat maps of the south pole show that the so-called tiger stripes, giant fissures that are the source of the geysers, are warm along almost their entire lengths, researchers said. These more precise new measurements reveal temperatures of at least minus 135 degrees Fahrenheit. The warmest regions along the tiger stripes correspond to two of the jet locations seen in Cassini images. “These spectacular new data will really help us understand what powers the geysers. The surprisingly high temperatures make it more likely that there’s liquid water not far below the surface,” said John Spencer, Cassini scientist at the Southwest Research Institute in Boulder, Colo. The jets blast off the surface into space. “Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life,” said Dennis Matson, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “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.” Scientists are hoping that microbial life might turn out to exist in a wet interior of the moon, though other factors, such as a lack of sunlight, could make that difficult. Cassini came within 30 miles (48 km) of Enceladus, researchers said. When it flew through the plumes it was 120 miles (190 km) away. An additional flyby is scheduled for August.