CICLOPS: Cassini Imaging Central Laboratory for OPerationS

High-Phase Plumes
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Saturn's moon Enceladus, imaged at high phase, shows off its spectacular water ice plumes emanating from its south polar region.

This image was captured at a phase, or Sun-Enceladus-spacecraft, angle of 159 degrees so that sunlight would reveal the backlit plumes. See PIA11688 to learn more.

Sunlight brightly illuminates terrain on the left. Light reflected off Saturn illuminates the rest of the moon more dimly. This view looks toward the trailing hemisphere of Enceladus (504 kilometers, 313 miles across). North is up.

Background stars, elongated by the movement of the spacecraft during the exposure, are also visible.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Oct. 13, 2009. The view was obtained at a distance of approximately 431,000 kilometers (268,000 miles) from Enceladus. Image scale is 3 kilometers (2 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Equinox Mission visit, and

Credit: NASA/JPL/Space Science Institute
Released: September 3, 2010 (PIA 12713)
Image/Caption Information
  High-Phase Plumes
PIA 12713

Avg Rating: 9.47/10

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Alliance Member Comments
NeKto (Sep 20, 2010 at 2:57 PM):
DoLMJ, thanks for the info. it seams this is a case of equilibrium. i had thought enough particls in the E ring would be lost to solar wind as well as disassociated and or ionized by solar radiation to be swept away by magnetic forces. Enough particle loss that it would leave less mass to fall back on Enceladus than is ejected. this system is more stable than i thought.
Dragon_of_Luck_Mah_Jonng1971 (Sep 17, 2010 at 10:02 AM):
NeKto, ijusth: I found the answer on the Cassini Mission main page.
When I searched on this page for 'E ring' I got many results, the interesting one is the 3rd one of 'News' :Home > News & Features > Cassini Science League > 'How a Celestial Snowblower Runs a Ring Around Saturn'. ( Published on March 23, 2010 )
( Type E ring followed by the enter key into the search window even if the page may indicate 'no results found' before pressing the enter key. )

The particles of Enceladus' jets are falling on Enc or making it into the E ring. Those ones in the E ring are falling back on Enc within one or two orbits or falling back on Enc after a much longer stay in the ring, but estimated not to be for more than 400 years. Some very few make it from the E ring into the magnetosphere. But material from impact cratering in the present on Enceladus is more than the particles lost to the magnetosphere I think. Thus Enceladus doesn't shrink. Enceladus is getting also material from micrometeorites.
(Even if scientists say that Tethys is brighter than Dione because it's getting material from the E ring, too, I think that the material from impacts and from micrometeorites on Enc is enough that Enceladus doesn't shrink although giving some material to Tethys. )

NeKto: This question has been answered by carolyn in 2009 already, the jets produce a thrust that is only miniscule.
NeKto (Sep 16, 2010 at 1:14 PM):
ijusth; i asked the same question about change in mass in March. no answers yet. on the question of where any shrinking might end, as i understand it, the gravitational friction that is the best hypothesis for providing the heat that powers the jets would become inefective in a much smaller body. Thus, if Enceladus is shrinking, the venting should stop from lack of heat long before Enceladus gets small enough to break up.
ijusth (Sep 7, 2010 at 8:12 PM):
here is another question about the jets on this or any of the other smaller moons. This outgassing has been going on for millions if not hundreds of millions of years. Wouldn't this make the moon shrink? Thus this would mean it was much larger at one point and in the future will shrink to a point where it will break up ... or is this way offbase.
NeKto (Sep 7, 2010 at 5:33 PM):
But seriously folks; do the jets produce enough thrust to measurably move the orbit of Enceladus?
p.s. Red dragon is quite correct about the image!
Red_dragon (Sep 6, 2010 at 3:05 AM):
Amazing image. Details on Enceladus' night side, the plumes... keep them coming.
NeKto (Sep 3, 2010 at 5:38 PM):
The impulse engine do not appear to be accelerating the space craft, Captain.

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