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Saturn's moon Enceladus 
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Joined: Fri Mar 13, 2009 4:18 pm
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A little closer to home...

I've been reading up on planetary ring systems, and there are some pretty amazing photos of ring systems here in our own solar system, where ring systems have been photographed around Saturn, Jupiter, and Uranus.

Saturn can brag of being the subject of the most spectacular ring photos, mostly from the spacecraft Cassini, currently orbiting it.

This is Saturn eclipsing the sun, in an exaggerated-color composite photo. The Earth is a tiny blue/white dot between between some of the outer rings to the left of Saturn, a little above center (click the image for the full-size version from NASA):

Image

The inset in this one shows a magnified view of the Earth from that position; the smudge at its upper left is the moon:

Image

Another large photo of Saturn and its rings, partially in shadow, from Cassini.

The rings are generated and stirred by larger bodies, such as the planets and their moons. Here's a gif animation of a ring being rippled by gravity as the moon Prometheus goes past it. The moon going by on the outer side is Pandora.

One of the most fascinating of those ring-stirring moons is Saturn's moon Enceladus. Cassini caught Enceladus churning through its ring during that same eclipse pass in which it caught the full Saturn image at the top of this post:

Image

Enceladus is a little icy ball only 500 km in diameter. Cassini flew within 50 km (!) of it to get this detailed surface image (click photo for larger):

Image

But Cassini also found something much more interesting there:

Image

Fountains of water ice crystals are jetting into space from four long, parallel gashes across Enceladus' south polar region; Cassini actually flew *through* these plumes and sampled their composition directly. The plumes are generating the ring of Saturn through which Enceladus orbits. Scientists think they're caused by volcanic activity within Enceladus; the volcanic ejection of ice rather than magma is called "cryovulcanism." Cassini was able to pick up thermal readings from the gashes, called by the rather silly name "Tiger Stripes":

Image

This makes Enceladus the fourth confirmed volcanic body in our solar system, along with Earth, Neptune's moon Triton, and Jupiter's Io; it's also one of the most likely to contain liquid water, and possibly some form of life. All that from this pretty little marble in one of Saturn's rings:

Image


Mon Jun 22, 2009 7:34 pm
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Ahhh Cassini probe!!

I followed it since is launch with nasa mails "where cassini is now?", i remember some wonderful sound from his approach to the planet!!

maybe somewhere they have yet this sounds uploaded somewhere!!


Tue Jun 23, 2009 1:16 am
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SEPET wrote:
Ahhh Cassini probe!!

I followed it since is launch with nasa mails "where cassini is now?", i remember some wonderful sound from his approach to the planet!!

maybe somewhere they have yet this sounds uploaded somewhere!!

Sounds?


Tue Jun 23, 2009 1:39 pm
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Yes, at some point they switch on a mic inside the probe and transmit it back to heart, i know what you are thinking "sounds in space???" but i think they mean inside sound from space... i check for that JPL mail.


Tue Jun 23, 2009 3:26 pm
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here the mail:

Quote:
INTERNET AUDIO ADVISORY December 15, 2000

"SOUNDS" OF OUTER SPACE NEAR JUPITER NOW ONLINE

NASA's Cassini spacecraft, approaching Jupiter, is detecting waves in the
thin gas of charged particles that fills the space between the Sun and its
planets. The waves are in low radio frequencies, which have been converted
to sound waves to make the patterns audible.

A brief audio clip is available at:

http://www.jpl.nasa.gov/cassini/acoustic .

The audio clip comes from waves that were detected by Cassini on Dec. 8,
at a distance of about 23 million kilometers (14 million miles) from
Jupiter. They are likely to have derived from an interaction of the
magnetic field that surrounds Jupiter and the solar wind of particles
speeding away from the Sun, said Cassini science team member Dr. William
Kurth of the University of Iowa, Iowa City.

Cassini, a cooperative mission of NASA, the European Space Agency and the
Italian Space Agency, will pass Jupiter on Dec. 30 for a gravity boost to
reach its ultimate destination, Saturn. The Jet Propulsion Laboratory,
Pasadena, Calif., manages Cassini for NASA's Office of Space Science,
Washington, D.C. JPL is a division of the California Institute of
Technology, Pasadena.


But looks like they moved the link above the mail was from december 2000.... so a little old....


Tue Jun 23, 2009 3:33 pm
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Huh, that would have been neat. I found a few copies of the article on the site

http://saturn.jpl.nasa.gov/news/newsrel ... 0001230-2/
http://saturn.jpl.nasa.gov/news/newsrel ... e20001215/

but the links to the audio are just as broken as the old newsletter. :P

Oh, here's one from Saturn, though!

http://www.jpl.nasa.gov/multimedia/cass ... ot-wav.wav

Man, there's some cool stuff in that site's multimedia section, like this approach to Hyperion

http://saturn.jpl.nasa.gov/multimedia/v ... _movie.mov

and then a close flyover

http://saturn.jpl.nasa.gov/video/videod ... videoID=97

Ah! And a gif animation of Enceladus' plumes:

http://saturn.jpl.nasa.gov/multimedia/v ... _movie.gif

And Rhea going by Mimas and Enceladus:

http://saturn.jpl.nasa.gov/multimedia/v ... _movie.gif


Tue Jun 23, 2009 5:40 pm
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Ehehe i told you!!!


Wed Jun 24, 2009 4:59 am
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Image
image by NASA (source)

March 2nd Cassini image of Enceladus 717,000 km away, over Saturn's rings.


Wed Mar 10, 2010 7:59 am
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This article

http://www.boston.com/bigpicture/2010/0 ... aturn.html

has 30 spectacular images from Cassini, including close-ups of the "Tiger Stripes" and really sharp pictures of the ice plumes on the horizon of the moon. I'll steal just a few; according to the captions on the page above, they were taken by Cassini in late 2009, and the trench in the close-up is called Baghdad Sulcus, one of the four "Stripes." Images by NASA:

Image
("looking toward the moon Enceladus, seen at top" ... "Light passing through Saturn's atmosphere creates the bright arc seen from the top to the bottom of the image")

Image

Image

Image
("approximately 2,028 km away")

Image
("image covers approximately 12 km (7.5 mi) from side to side")


Sat Jun 05, 2010 5:54 pm
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And of course there are many more images at NASA's Cassini Saturn mission gallery:

http://saturn.jpl.nasa.gov/photos/


Mon Jun 07, 2010 8:35 am
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