Picture of ice fountains on one of Saturn's moons

[Rocker5150]

I thought this was extremely interesting:

http://antwrp.gsfc.nasa.gov/apod/image/ ... ni_big.jpg


Explanation: Fountains of ice shoot out from Saturn's moon Enceladus. Clear discovery images of the fountains were made using observations from the robot Cassini spacecraft currently orbiting Saturn. During a recent pass, Cassini was programmed to look back toward the Sun where Enceladus would appear as a thin crescent. From this vantage point, particles emitted from the surface would better show themselves by reflecting sunlight. The tactic was successful -- the above frame shows several plumes emanating from regions previously known to contain gashes in the surface dubbed tiger stripes. Cassini detected an increase in particle emissions from these regions during a July flyby. Some of these ice particles likely contribute to the make up of Saturn's mysterious E ring.


So what is going on here? Would this discovery imply there is a relatively fast temperature change that allows for the fountains to freeze up while spouting? Or could it be that they are somewhat frozen, but not enough to stop the flow completely? Imagine how awesome these must look from the surface!


-Kevin

[wolveraptor]

There could easily be a quick temperature change, assuming Enceladus has a thin atmosphere that retains heat poorly. Combined with heat-reflective surface of ice, the only thing that must be heating the moon's ice to melting point must be the gravitational contortion of the planet by Saturn.

[Rocker5150]

This article talks about what happened when they used the Composite Infrared Spectrometer (CIRS) on the moon. Spilker is the Deputy Project Scientist for the Cassini-Huygens mission.

http://www.planetary.org/news/2005/0730 ... _Spew.html

"What CIRS saw at Enceladus was a stunner. The team expected to see a relatively homogeneous temperature map, warmest where the Sun's rays strike the moon most directly, and coolest in the night side and at the poles. But CIRS found a whopping hot spot at the south pole of Enceladus. "It was a complete surprise," Spilker said. But an even greater surprise was in store from data captured closer in. "The hottest features in the CIRS data appear to correspond with the tiger stripes. There is clear evidence that the hottest footprint straddles one of those tiger stripes."
The high temperatures observed by CIRS in the tiger stripes open up the exciting possibility that there is a reservoir of liquid, or at least slushy, water-ammonia below Enceladus' south pole. The hot source is forcing water vapor out of vents, forming a tenuous atmosphere at Enceladus' south pole.
The discovery is thrilling. Recent activity on Enceladus has been considered a possibility since Voyager, but there is no known explanation for how a body as small as Enceladus can generate enough internal heat to drive active geology. Spilker grappled with the problem: "Radiogenic heating is impossible for a body the size of Enceladus, there might not be much heat left over -- and tidal heating, from what we understand about how the tidal heating works, that’s not enough." But there's hope for people who want to explain Enceladus, she said. "I think the key here is that it’s not a global heat source, it’s really concentrated at the south pole. And that might make the problem a little easier in that you only need a localized heat source. How it got there, why it’s still there, -- people are busy scratching their heads!"


Here is a nice shot of the 'tiger stripes':

http://antwrp.gsfc.nasa.gov/apod/ap050906.html



-Kevin

[Drooling Iguana]

Probably the waste heat from an alien listening post.

[drachefly]

Or better yet, that's the drillhole the aliens that evolved in the liquid interior made so they could get to the surface.
:o

[wolveraptor]

"I think the key here is that it’s not a global heat source, it’s really concentrated at the south pole. And that might make the problem a little easier in that you only need a localized heat source. How it got there, why it’s still there, -- people are busy scratching their heads!"

Well damn, thanks for shitting all over my theory.

In all seriousness, the gravitational pull from Saturn couldn't create a localized heating like that. It'd have to be something else.