Cassini spacecraft reveals 101 geysers and more on icy Saturn moon

Jul 29, 2014 by Preston Dyches
This view looks across the geyser basin of Saturn's moon Enceladus, along fractures spewing water vapor and ice particles into space. Cassini scientists have pinpointed the source locations of about 100 geysers and gained new insights into what powers them. Credit: NASA/JPL-Caltech/SSI

Scientists using mission data from NASA's Cassini spacecraft have identified 101 distinct geysers erupting on Saturn's icy moon Enceladus. Their analysis suggests it is possible for liquid water to reach from the moon's underground sea all the way to its surface.

These findings, and clues to what powers the geyser eruptions, are presented in two articles published in the current online edition of the Astronomical Journal.

Over a period of almost seven years, Cassini's cameras surveyed the south polar terrain of the small moon, a unique geological basin renowned for its four prominent "tiger stripe" fractures and the of tiny icy particles and water vapor first sighted there nearly 10 years ago. The result of the survey is a map of 101 geysers, each erupting from one of the tiger stripe fractures, and the discovery that individual geysers are coincident with small hot spots. These relationships pointed the way to the geysers' origin.

After the first sighting of the geysers in 2005, scientists suspected that repeated flexing of Enceladus by Saturn's tides as the moon orbits the planet had something to do with their behavior. One suggestion included the back-and-forth rubbing of opposing walls of the fractures generating frictional heat that turned ice into geyser-forming vapor and liquid.

Alternate views held that the opening and closing of the fractures allowed from below to reach the surface. Before this new study, it was not clear which process was the dominating influence. Nor was it certain whether excess heat emitted by Enceladus was everywhere correlated with geyser activity.

To determine the surface locations of the geysers, researchers employed the same process of triangulation used historically to survey geological features on Earth, such as mountains. When the researchers compared the geysers' locations with low-resolution maps of thermal emission, it became apparent the greatest geyser activity coincided with the greatest thermal radiation. Comparisons between the geysers and tidal stresses revealed similar connections. However, these correlations alone were insufficient to answer the question, "What produces what?"

The answer to this mystery came from comparison of the survey results with high-resolution data collected in 2010 by Cassini's heat-sensing instruments. Individual geysers were found to coincide with small-scale hot spots, only a few dozen feet (or tens of meters) across, which were too small to be produced by frictional heating, but the right size to be the result of condensation of vapor on the near-surface walls of the fractures. This immediately implicated the as the signature of the geysering process.

"Once we had these results in hand, we knew right away heat was not causing the geysers, but vice versa," said Carolyn Porco, leader of the Cassini imaging team from the Space Science Institute in Boulder, Colorado, and lead author of the first paper. "It also told us the geysers are not a near-surface phenomenon, but have much deeper roots."

Thanks to recent analysis of Cassini gravity data, the researchers concluded the only plausible source of the material forming the geysers is the sea now known to exist beneath the ice shell. They also found that narrow pathways through the ice shell can remain open from the sea all the way to the surface, if filled with .

In the companion paper, the authors report the brightness of the plume formed by all the geysers, as seen with Cassini's high-resolution cameras, changes periodically as Enceladus orbits Saturn. Armed with the conclusion that the opening and closing of the fractures modulates the venting, the authors compared the observations with the expected venting schedule due to tides.

They found the simplest model of tidal flexing provides a good match for the brightness variations Cassini observes, but it does not predict the time when the plume begins to brighten. Some other important effect is present and the authors considered several in the course of their work.

Explore further: Yellowstone geyser eruptions influenced more by internal processes

More information: "Tidally Modulated Eruptions on Enceladus: Cassini ISS Observations and Models." Francis Nimmo et al. 2014, Astronomical Journal 148 46. DOI: 10.1088/0004-6256/148/3/46

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User comments : 7

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cantdrive85
1 / 5 (9) Jul 29, 2014
A little confirmation bias goes a long way, especially when your only "known" mechanisms are driven by gravity.

Maybe a lesson from those who understand the electric discharge of bodies in plasma would help these neophytes.

http://phys.org/n...ric.html

Enceladus is experiencing similar discharge from it's own interaction with Saturn's electrical environment.

http://www.jpl.na...2011-120
RealScience
4.5 / 5 (8) Jul 29, 2014
@CD - A little confirmation bias goes a long way, especially when YOUR only "known" mechanisms are driven by electric fields.

Tidal heating is well known - tidal forces and tidal friction can be calculated, and the calculations match well with what we observe in our moon's orbit.

There certainly are wild electrical phenomena around the gas giants and their inner moons, and mainstream astronomy and physics science recognizes many of these. The links that you post even confirm this!

So not only is gravity and the resulting tidal forces at least a major factor in Enceladus's heating, but your implication that the mainstream only knows about gravity is just plain silly. It is you who is the one-force pony.

cantdrive85
1 / 5 (3) Jul 30, 2014
Tidal heating is well known - tidal forces and tidal friction can be calculated,


But it doesn't really match observations though, does it.

http://phys.org/n...ong.html

It is you who is the one-force pony.


Well, being the the electric force is 1,000,000,000,000,000,000,000,000,000,000,000,000,000 times stronger than gravity, I do feel one has a greater significance than the other. That being said, it certainly doesn't mean EU disregards gravity;
This quote from https://www.thund...gravity/ ;
"The Electric Universe paradigm fully accepts the existence and importance of gravitation to the practice of physical science and cosmological modelling."
Lex Talonis
1 / 5 (1) Jul 30, 2014
It would be a good place to sail a nuclear submarine.

A big and well insulated on of course.

And the water etc., would protect you from the radiation.
barakn
5 / 5 (3) Jul 30, 2014
Thanks, cd, for another revealing article at https://www.thund...gravity/
RealScience
5 / 5 (5) Jul 30, 2014
@CD - The electrical force may be many orders of magnitude stronger than gravity on an individual particle basis, but like charges repel and opposite charges attract so the electrical force tends to cancel itself while gravity just keeps adding up in large masses. That's why the moon orbits the earth due to gravity.

As for heating of moons and your link to the Io article, the article hints that the magnetic field may shift the location of the volcanoes, not that it produce most of the heat. Even the spectacular electrical arc that terminates on Io is maxes out at about 1.2 teraWatts, and is thus roughly two orders of magnitude less than tidal heating estimates and hotspot output measurements.

Captain Stumpy
5 / 5 (3) Jul 31, 2014
That being said, it certainly doesn't mean EU disregards gravity;
given the model of the electric sun in your hysterical pseudoscience then I would have to disagree with that comment

also, your LINK is to a KNOWN PSEUDOSCIENCE SITE
if there is legitimate science to be shared, you SHOULD be able to find it from a reputable source that is peer reviewed and relevant to the subject.

Considering that you usually post from your https://www.thunderbutts.com site, this only reinforces your PSEUDOSCIENCE descriptor

perhaps you would like to prove your EU legitimate once and for all?
I can arrange a public debate with some legitimate physicists for your EU team to debate. You can come too, cd. you might learn something.

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