Enceladus Plume Search, Nov. 27 |
Enceladus Plume Search, Nov. 27 |
Nov 28 2005, 05:56 PM
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#31
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Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
Here's a map of the south polar region, based on Steve Alber's latest cylindrical projection (click for larger image):
This is an orthonormal projection, so the limb is the equator and the south pole ("tiger scratch" feature) is at the center of the image. -------------------- |
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Nov 28 2005, 06:29 PM
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#32
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Member Group: Members Posts: 903 Joined: 30-January 05 Member No.: 162 |
Maybe I am 'seeing' too much into your map, but I keep thinking of Miranda and race tracks. . . . .
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Nov 28 2005, 06:41 PM
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#33
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Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
Found this image of the south polar region (approximate south pole marked with circle, click for larger image):
raw image -------------------- |
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Nov 28 2005, 07:21 PM
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#34
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Newbie Group: Members Posts: 13 Joined: 28-November 05 Member No.: 587 |
The features seen in these images are located at the south pole. At the time the images were taken, the Sun was directly below Enceladus as seen from the spacecraft, but the spacecraft was roughly in the plane of the satellites. So the center of the bright limb is right about at the south pole.
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Nov 28 2005, 07:37 PM
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#35
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Senior Member Group: Members Posts: 3008 Joined: 30-October 04 Member No.: 105 |
The ridges and wrinkles in that region are a strong indication of tectonics and therefore heat flow, so it makes perfect sense that there will be venting and visible plumes.
Now to figure out why.... --Bill -------------------- |
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Nov 28 2005, 08:17 PM
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#36
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Senior Member Group: Members Posts: 1669 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
QUOTE (tedstryk @ Nov 28 2005, 04:49 PM) I think that there was always suspicion, but they wanted to avoid the humiliation of announcing a great discovery and then having to retract it. I would certainly hope there was a healthy suspicion all along. In the previous forum discussion a few months ago, I expressed some of my own suspicion, even if it was tempered by some ensuing (and perhaps not entirely convincing?) replies. On another note, I just made a south polar view in a perspective projection, available here: http://laps.noaa.gov/albers/sos/saturn/enc..._cyl_www_P4.jpg -------------------- Steve [ my home page and planetary maps page ]
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Nov 28 2005, 08:44 PM
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#37
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Member Group: Members Posts: 624 Joined: 10-August 05 Member No.: 460 |
QUOTE (jmknapp @ Nov 28 2005, 10:56 AM) Here's a map of the south polar region, based on Steve Alber's latest cylindrical projection (click for larger image): This is an orthonormal projection, so the limb is the equator and the south pole ("tiger scratch" feature) is at the center of the image. Stretch Marks? |
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Nov 28 2005, 08:47 PM
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#38
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
I'm attaching a rendering I did showing the viewing geometry at 17:38 on November 27, 2005. Cassini took several images at roughly this time, for example these two:
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=54839 http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=54840 I then rotated one of the Cassini images where the limb is overexposed to match the orientation of the rendered image, resized it to match the rendering size and pasted the plumes into the rendering. This confirms that the source of the brightest plume (assuming we really are seeing plumes which seems very likely) is near the south pole. The fainter plumes appear farther from the pole. It should be noted that this might be an illusion, the brightest plume might be at the same distance or farther from the pole than the fainter ones if its source is well inside Enceladus' 'disc'. |
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Nov 28 2005, 09:03 PM
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#39
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
QUOTE (tedstryk @ Nov 28 2005, 04:49 PM) I think that there was always suspicion, but they wanted to avoid the humiliation of announcing a great discovery and then having to retract it. Yes, a STRONG suspicion (the same I had! )... Anyway, I tried to code with colors the huge dinamic range covered by 3 images taken with increasing exposure time (N00043435/36/37): -------------------- I always think before posting! - Marco -
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Nov 28 2005, 09:59 PM
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#40
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Senior Member Group: Moderator Posts: 3241 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Special release for the Enceladus plume:
http://ciclops.org/view_event.php?id=45 Spray Above Enceladus http://ciclops.org/view.php?id=1652 this release shows the infamous images from January showing a brighting of the limb of Enceladus. Because this looked similar to artifacts seen at other moons, this was brushed off as an artifact as well. However, more indepth analysis of this sequence of images revealed that the" plume" was in fact real. Fountains of Enceladus http://ciclops.org/view.php?id=1688 In perhaps the fastest image release ever, this release shows the new jets found near in the south polar region of Enceladus. -------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Nov 28 2005, 10:01 PM
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#41
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Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
QUOTE (Bjorn Jonsson @ Nov 28 2005, 04:47 PM) This confirms that the source of the brightest plume (assuming we really are seeing plumes which seems very likely) is near the south pole. The fainter plumes appear farther from the pole. It should be noted that this might be an illusion, the brightest plume might be at the same distance or farther from the pole than the fainter ones if its source is well inside Enceladus' 'disc'. This might help pin things down, assuming I got it accurately. Here's the viewing geometry I think, from the vantage point of an observer 100,000 km directly above the south pole: -------------------- |
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Nov 28 2005, 10:31 PM
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#42
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Member Group: Members Posts: 548 Joined: 19-March 05 From: Princeton, NJ, USA Member No.: 212 |
This news just released by CICLOPS website
"The Fountains of Enceledus" http://ciclops.org/view_event.php?id=45 "In a wonderful start to the Holiday season, Cassini imaging scientists are delighted by recent sightings of fountain-like plumes towering above Saturn's moon Enceladus. A fine spray of small, icy particles, emanating from the warm, geologically unique province surrounding the south pole of Enceladus and believed now to supply the material comprising Saturn's E ring, was first observed in images taken back on Jan. 16, 2005. Images of a crescent Enceladus returned by Cassini this past weekend show multiple plumes in striking detail. Stay tuned for future announcements on the sightings of the Enceladus plumes". check the link for more info and images |
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Guest_Sunspot_* |
Nov 28 2005, 10:48 PM
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#43
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Guests |
What's also striking is how obvious the plumes are - even in the RAW unprocessed images posted online.
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Nov 28 2005, 11:29 PM
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#44
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Member Group: Members Posts: 548 Joined: 19-March 05 From: Princeton, NJ, USA Member No.: 212 |
QUOTE (Sunspot @ Nov 28 2005, 10:48 PM) What's also striking is how obvious the plumes are - even in the RAW unprocessed images posted online. Yes, this is a truly outstanding mission highlight !!! Enceledus has been a mission star almost as bright as Titan. To see those plumes so clearly, and they have been on the hunt !! NASA/ESA should consider an Enceledus lander to complement a Europa mission and follow-up for Titan. |
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Nov 28 2005, 11:29 PM
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#45
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Member Group: Members Posts: 470 Joined: 24-March 04 From: Finland Member No.: 63 |
Looking at the raws I noticed that the whole background of the images is light, not just the plumes. This is especially evident on the overexposed images of encaladus:
Notice how the background space is lighter than the "dark side" of Encaladus. Does this mean that plume material is all around, maybe making up a donut of the material around Encaladus's orbit? -------------------- Antti Kuosmanen
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