Friday, March 28, 2008

The Cassini–Huygens spacecraft has discovered “organic material” and water spewing from a geyser on one of Saturn‘s moons, Enceladus. According to NASA, the discovery was made when Cassini flew by the moon on March 12.

“A completely unexpected surprise is that the chemistry of Enceladus, what’s coming out from inside, resembles that of a comet. To have primordial material coming out from inside a Saturn moon raises many questions on the formation of the Saturn system,” said Hunter Waite, principal investigator for the Cassini Ion and Neutral Mass Spectrometer at the Southwest Research Institute located in San Antonio, Texas.

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 high-resolution heat maps of the south pole by Cassini’s Composite Infrared Spectrometer show that the so-called tiger stripes, giant fissures that are the source of the geysers, are warm along almost their entire lengths, and reveal other warm fissures nearby. These more precise new measurements reveal temperatures of at least minus 93 degrees Celsius (minus 135 Fahrenheit.) That is 17 degrees Celsius (63 degrees Fahrenheit) warmer than previously seen and 93 degrees Celsius (200 degrees Fahrenheit) warmer than other regions of the moon. The warmest regions along the tiger stripes correspond to two of the jet locations seen in Cassini images.

“Enceladus has got warmth, water and organic chemicals, some of the essential building blocks needed for life. 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,” said Dennis Matson, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

At closest approach, Cassini was only 30 miles from Enceladus. When it flew through the plumes it was 120 miles from the moon’s surface. Cassini’s next flyby of Enceladus is in August.