Cassini Tastes Organic Material at Saturn's Geyser Moon

Mar 26, 2008
Cassini Tastes Organic Material at Saturn's Geyser Moon
Heat radiating from the entire length of 150 kilometer (95 mile)-long fractures is seen in this best-yet heat map of the active south polar region of Saturn's ice moon Enceladus. Credit: NASA

NASA's Cassini spacecraft tasted and sampled a surprising organic brew erupting in geyser-like fashion from Saturn's moon Enceladus during a close flyby on March 12. Scientists are amazed that this tiny moon is so active, "hot" and brimming with water vapor and organic chemicals.

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 found in a comet. The jets themselves harmlessly peppered Cassini, exerting measurable torque on the spacecraft, and providing an indirect measure of the plume density.

"A completely unexpected surprise is that the chemistry of Enceladus, what's coming out from inside, resembles that of a comet," said Hunter Waite, principal investigator for the Cassini Ion and Neutral Mass Spectrometer at the Southwest Research Institute in San Antonio. "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. Comets have tails and orbit the sun, and Enceladus' 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," said Waite.

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 135 degrees Fahrenheit. That is 63 degrees Fahrenheit warmer than previously seen and 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.

"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 on the Composite Infrared Spectrometer team at the Southwest Research Institute in Boulder, Colo.

Previous ultraviolet observations showed four jet sources, matching the locations of the plumes seen in previous images. This indicates that gas in the plume blasts off the surface into space, blending to form the larger plume.

Images from previous observations show individual jets and mark places from which they emanate. New images show how hot spot fractures are related to other surface features. In future imaging observations, scientists hope to see individual plume sources and investigate differences among fractures.

"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."

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.

Source: NASA

Explore further: NASA's sun watching observatory sees mid-level solar flare on Dec. 16, 2014

add to favorites email to friend print save as pdf

Related Stories

How can we search for life on icy moons such as Europa?

Nov 24, 2014

Our solar system is host to a wealth of icy worlds that may have water beneath the surface. The Cassini spacecraft recently uncovered evidence of a possible ocean under the surface of Saturn's moon, Mimas.

A close-up with a comet

Nov 11, 2014

Even as Tom Economou approached retirement age in 1994, he began planning an instrument for the European Space Agency's Rosetta mission to a comet. He still remembers the reaction of Riccardo Levi-Setti, ...

Cassini finds hints of activity at Saturn moon Dione

May 30, 2013

(Phys.org) —From a distance, most of the Saturnian moon Dione resembles a bland cueball. Thanks to close-up images of a 500-mile-long (800-kilometer-long) mountain on the moon from NASA's Cassini spacecraft, ...

Enceladus' jets reach all the way to its sea

Mar 20, 2013

Thanks to the Cassini mission we've known about the jets of icy brine spraying from the south pole of Saturn's moon Enceladus for about 8 years now, but this week it was revealed at the 44th Lunar and Planetary Science Conference outside Houst ...

Recommended for you

German named next head of European Space Agency

1 hour ago

Johann-Dietrich Woerner, head of German aerospace giant DLR, is to succeed Frenchman Jean-Jacques Dordain as next director-general of the European Space Agency, ESA announced on Thursday.

India launches biggest ever rocket into space

4 hours ago

India successfully launched its biggest ever rocket on Thursday carrying an unmanned capsule which could one day send astronauts into space, as the country ramps up its ambitious space programme.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

earls
5 / 5 (1) Mar 28, 2008
I'm personally more interested in the magnetic field and charge density the spacecraft encountered. Unfortunately, it seems to be of little to no concern to the project.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.