From the Institute of Physics website: Further confirmation of significant tidal force operating in the moon systems of the Gas Giants. Contributor Oldbrew and I have been working on the orbital configurations and have some news related to the Phi planetary discovery made earlier in the year here at the talkshop we’ll be posting about soon.
In 1980 and 1981 NASA’s Voyager 1 and 2 spacecraft flew past the ringed planet and found Enceladus’s surface unusually smooth. This suggested that something was erasing its craters. Then in 2005 the Cassini spacecraft discovered water vapour around Enceladus. Cassini soon found the surprising source: geysers around the moon’s south pole shoot water vapour and ice particles hundreds of kilometres above the surface. Planetary scientist Matthew Hedman of Cornell University and his colleagues have examined 252 near-infrared images from Cassini. “The brightness of the plume varied quite a bit,” says Hedman, who found it four times brighter when Enceladus is farthest from Saturn than when closest. These observations agree with a prediction made in a paper published in 2007 by Terry Hurford of the Goddard Space Science Center in Maryland, who had calculated how Enceladus would respond to Saturn’s tide.
Saturnian tides are weakest when Enceladus is farthest from the ringed planet, yet that is when the geysers are strongest. “It’s thedirection of the force rather than the magnitude that’s relevant,” Hedman says, noting that the geysers erupt through cracks that resemble the stripes of a tiger. “The tiger stripes are all oriented in one direction. According to the models, in part because of the particular orientation of the tiger stripes, the cracks are pulled open when Enceladus is furthest from the planet and slammed shut when it’s closest to the planet.” As a result, the moon vents the most material when most distant from Saturn.
Enceladus owes its geysers not only to the tides of Saturn but also to a resonance with Dione, a moon that lies beyond it. Saturn’s strong tides ought to make Enceladus’s orbit a perfect circle, but Enceladus revolves around Saturn twice in the same time Dione does once, so Dione’s periodic gravitational tugs keep the path of Enceladus slightly elliptical. This causes the tidal force on the moon to vary continuously as the satellite orbits Saturn, supplying the small moon with heat. Nevertheless, Enceladus has a more circular orbit around Saturn than any planet in the solar system does around the Sun.
The same phenomenon happens around Jupiter. Io is in resonance with Europa and Europa with Ganymede, so Io and Europa have slightly elliptical paths that cause the tidal force they feel to change constantly.
Hedman and colleagues describe their observations in Nature10.1038/nature12371.
Ken Croswell is a US-based astronomer and author of eight books on astronomy
Tallbloke's Talkshop 
Good stuff, there’s so much going on with the ‘big two’ gas giants.
Re Jupiter and Io, have a look at the graphic of Io’s plasma torus here.
http://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter#Role_of_Io
How’s that for interacting forces between planetary bodies? As they say:
‘The Io torus fundamentally alters the dynamics of the Jovian magnetosphere.’
NASA’s Juno mission is due to reach Jupiter in 2016 (launched 2011).
OB: Is your phone on?
http://en.wikipedia.org/wiki/File:Jupiter.Aurora.HST.mod.svg
Ganymede, Europa, and Io each leave a footprint in Jupiter’s aurora.
That may be why it is very difficult to detect the planets’ modulation of solar activity, because the public lacks any consistent observations of the sun’s poles.
For example, the Earth is known to have enormous, bursty flux transfer events, in which it connects with the sun, every 8 minutes. This should show some effect on the sun, and if it is in any way similar to the Jupiter system, this connection would occur at the sun’s poles.
Or ask this question, how would anyone observe Jupiter’s moons’ modulation of those powerful auoras, if you had no observation of its poles?
TB: it is now.
Btw Enceladus orbit 1.37~days x 170 (34×5) = 233.
5, 34 and 233 are all Fibonacci numbers.
“The tiger stripes are all oriented in one direction. According to the models, in part because of the particular orientation of the tiger stripes, the cracks are pulled open when Enceladus is furthest from the planet and slammed shut when it’s closest to the planet.” ”
Strange that they don’t offer photos or other OBSERVATIONS to claim confirmation, just models.
Of course if the jets are a plasma phenomenon similar to comets then the gravity bit is bogus.
Yeah, they need to get a guy in a space suit down there with a measuring rod to check some crack widths. 😉
Plasma? What makes you think that? The spectral analysis says water vapour.
tallbloke,
what makes it to altitude is ice crystals and water and no I am not talking about what is floating around in a Tokamak. I probably have the wrong term.
TB,
just remembered, do you have links to the actual data used to ID the water in the jets?? What I am wondering is if the scientists are saying water when they are IDing hydroxyl, as they have done in the past.
[Reply] No I haven’t – sorry.
There’s a rotation resonance between Saturn and Enceladus, IMO.
12 Enceladus = 37 Saturn rotations, every 16.444 (= 148 / 9) days.
‘Enceladus revolves around Saturn twice in the same time Dione does once’
So 6 Dione = 37 Saturn rotations, every 16.444 days.
A quick check suggests a similar phenomenon with Jupiter and Io rotations.
77 Jupiter = 18 Io
It’s well documented that Jupiter and Io interact very strongly via electro-magnetic forces:
‘As Io circles around Jupiter and through the plasma torus, an enormous electrical current flows between them. Approximately 2 trillion watts of power is generated.’
http://www.planetaryexploration.net/jupiter/io/io_plasma_torus.html
Perhaps magnetism is a significant factor in the Enceladus case too?
—
NB planetary moons have a 1:1 rotation/orbit period in most cases (but not the Earth’s moon).
[Reply] Good thinking. Except Earth’s Moon does have a tidally locked 1:1 relationship with Earth, turning once as it orbits once. That’s why we always see the same face.
“Moon’s orbit for dummies” for me then…
The Enceladus – Saturn magnetic link is already known.
‘Data from the Cassini spacecraft have revealed that the jets of gas and icy grains that emanate from the south pole of Enceladus become electrically charged and form an ionosphere, and the motion of Enceladus and its ionosphere through a magnetic bubble that surrounds Saturn acts like a dynamo, setting up a newly-discovered electrical current system that links the moon to the planet.’ (April 2011)
http://www.universetoday.com/85056/enceladus-and-saturn-are-linked-by-electromagnetic-currents/
OB: So, Enceladus linked to Saturn by electromagnetism. Io strongly linked to Jupiter by electromagnetism. NASA tells us of ‘flux tubes’ down which currents flow linking the planets with magnetospheres and the Sun. Tim Cullen and You and I have found hints of a linkage between spin rates and orbital periods. It’s all starting to make some sense isn’t it?