Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists propose alternate model for plume on enceladus

18.12.2006
What's causing all the commotion on Enceladus?

Last year, when the Cassini spacecraft discovered an enormous plume erupting on Enceladus, one of Saturn's moons, scientists speculated that liquid water lay at shallow depths beneath the icy surface.

Now, as reported in the Dec. 15 issue of the journal Science, researchers have proposed an alternate model to account for this spectacular plume.

"With a diameter of only 300 miles, Enceladus is a tiny moon; it would fit easily between Los Angeles and San Francisco," said Susan Kieffer, a geology professor and planetary scientist at the University of Illinois at Urbana-Champaign, and lead author of the Science paper. "This tiny satellite should be cold and inactive, like our own moon. But it isn't."

The surface of Enceladus is composed of water ice with traces of carbon dioxide. Part of this surface does appear old and cratered like Earth's moon, Kieffer said. "The south polar region, however, is geologically active, with many surface features, indicating current activity."

Kieffer, who holds a Charles R. Walgreen Jr. Chair at the U. of I., has studied geysers and volcanoes on Earth; on Io, a satellite of Jupiter; and on Triton, a satellite of Neptune.

Instruments on the Cassini spacecraft revealed a gigantic plume of gas, water vapor and ice particles erupting from Enceladus' surface. Some of the ice escapes the moon's feeble grasp and replenishes a ring of ice particles around Saturn, called the "E ring."

Initial reports speculated that chambers of liquid water lay close to the moon's surface and erupted in a giant geyser. The water would be near freezing, so scientists dubbed the model "Cold Faithful," after the familiar, but hotter, Old Faithful geyser in Yellowstone National Park.

"A problem with this model," Kieffer said, "is that 10 percent of the plume consists of the gases carbon dioxide, nitrogen and methane. You might get a carbon dioxide-driven liquid geyser there, but you can't put this much nitrogen and methane into liquid water at the low pressures found inside Enceladus."

Nitrogen and methane are nearly insoluble in liquid water, but highly soluble in frozen water – in an ice phase called clathrate. When clathrate is exposed to a vacuum, the gas molecules burst out, ripping the ice lattice to shreds and carrying the fragments away.

Kieffer and colleagues have proposed an alternate model to explain the plume on Enceladus. The gases in the plume, they propose, are dissolved in a reservoir of clathrate under the water ice cap in the south polar region. The clathrate model allows an environment that would be 80 to 100 degrees Celsius colder than liquid water, with a "Frigid Faithful" plume emanating from clathrates, rather than from liquid water reservoirs.

"Exposed to near-vacuum conditions by fractures at the south pole, the clathrates decompose violently, spewing out nitrogen, methane and carbon dioxide gases, and ice particles; as well as leaving fracture walls coated with water ice," said Kieffer, who is also a professor in the university's Center for Advanced Study, one of the highest forms of campus recognition. "Some ice particles and ice coatings evaporate to produce the water vapor observed with the other gases," she said.

Active tectonic processes at the south pole cause continuous formation of cracks in the ice, through which many separate vents create a plume. The total discharge is comparable to that of Old Faithful, but the plume is enormously bigger because it is erupting at very low gravity into the near vacuum of space.

"We propose that cracks in Enceladus' ice cap may be opening and closing continuously, producing the spectacular plume we see reaching high above Enceladus' surface," Kieffer said. "Even if conditions are as cold as our model suggests, there is no problem launching ice particles into Saturn's E-ring."

James E. Kloeppel | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Physics and Astronomy:

nachricht Solar wind impacts on giant 'space hurricanes' may affect satellite safety
19.09.2017 | Embry-Riddle Aeronautical University

nachricht Integrated lasers on different surfaces
19.09.2017 | The Agency for Science, Technology and Research (A*STAR)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

IVAM’s LaserForum visits the Swiss canton of St. Gallen with the topic ultrashort pulse lasers

06.09.2017 | Event News

 
Latest News

The Wadden Sea and the Elbe Studied with Zeppelin, Drones and Research Ships

19.09.2017 | Earth Sciences

Digging sensors out of an efficiency hole

19.09.2017 | Materials Sciences

Solar wind impacts on giant 'space hurricanes' may affect satellite safety

19.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>