Enceladus PDS image products |
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Enceladus PDS image products |
 Oct 6 2011, 12:41 AM
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#31
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 Administrator  Group: Chairman Posts: 13250 Joined: 8-February 04 Member No.: 1  |
QUOTE (Stu @ Oct 5 2011, 04:21 PM)  and on NASA's own websites Yeah, someone should do something about that.  |
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Oct 6 2011, 02:09 AM
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#32
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 Member Group: Members Posts: 352 Joined: 28-August 07 From: San Francisco Member No.: 3511 |
Wondrous !
-------------------- Ladies and Gentlemen, Sample Return...
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Oct 10 2011, 08:33 PM
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#33
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 Senior Member Group: Members Posts: 3534 Joined: 1-October 05 From: Croatia Member No.: 523 |
Subject: Enceladus plume temporal variance. 3 NAC clear frames taken roughly at 50 second intervals, unsharped and contrast enhanced:
Can you pick up material from a couple of vents going up in "puffs"? I don't think this can be explained by parallax/rotation, the observed rotation of Enceladus is too small for that. I strongly believe this is a genuine variation in output flux on a timescale of a minute. -------------------- |
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Oct 10 2011, 08:43 PM
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#34
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Senior Member Group: Members Posts: 3534 Joined: 1-October 05 From: Croatia Member No.: 523 |
Here's a ratio flicker gif. First frame is frame #2 divided by #1, second frame is frame #3 divided by #2. Shows subtle change in plume appearance from one frame to another better.
Notice alternating dark/bright clouds in the plume to the left and to the right. At least two distinct puffs seem to be present in each plume. There's a hint of variation in a third plume at around 12 o'clock but it's much less convincing than these two. I tried to do a (very) rough measurement of the displacement in the right hand plume during the 50-ish seconds between snapshots and I got a radial velocity of ~250 m/s. I haven't double-checked this. In reality the flow is not in the viewing plane so any number would probably underestimate the real speed. I've been looking to see if anything like this could be noticed in past plume images and I don't recall seeing anything convincing before. -------------------- |
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Oct 10 2011, 09:01 PM
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#35
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 Senior Member Group: Members Posts: 2932 Joined: 4-November 05 From: North Wales Member No.: 542 |
I'm not sure if it's two variable vents or just one that is changing direction, but yes, I agree there is real variation there. A nice obsevation! It's easy to believe - there's no reason why they shouldn't be variable. Perhaps the vent has an ice boulder stuck in its throat. Even in the absence of a mobile obstruction rapid flow is often accompanied by instability/turbulence. I wonder if it has a regular periodicity? Maybe it's singing a low lunar note.
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Oct 10 2011, 10:08 PM
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#36
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 Member Group: Members Posts: 555 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
QUOTE (ugordan @ Oct 10 2011, 10:33 PM) Subject: Enceladus plume temporal variance. .... Can you pick up material from a couple of vents going up in "puffs"? I don't think this can be explained by parallax/rotation, the observed rotation of Enceladus is too small for that. I strongly believe this is a genuine variation in output flux on a timescale of a minute. It's very interesting, but I think, that it's game of shadows. -------------------- |
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Oct 11 2011, 02:49 AM
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#37
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Member Group: Members Posts: 352 Joined: 28-August 07 From: San Francisco Member No.: 3511 |
Has the long shadow been explained?
-------------------- Ladies and Gentlemen, Sample Return...
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Oct 12 2011, 02:34 AM
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#38
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 Member Group: Members Posts: 508 Joined: 3-December 04 From: Boulder, Colorado, USA Member No.: 117 |
QUOTE (ugordan @ Oct 10 2011, 02:33 PM) Subject: Enceladus plume temporal variance. Awesome find! It looks pretty convincing to me. Congratulations Gordan! John |
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Oct 12 2011, 10:22 PM
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#39
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 Senior Member Group: Moderator Posts: 6480 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Re the long shadow: Looks to me like that's probably an effect of the shadow of Enceladus itself; parts of the plumes are in sunlight, some aren't. There are other plumes in the foreground of the shadowed region, which makes it look a little weird but that's a perspective effect.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Oct 13 2011, 06:24 PM
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#40
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 Director of Galilean Photography Group: Members Posts: 709 Joined: 15-July 04 From: Austin, TX Member No.: 93 |
Isn't that mostly Saturnshine lighting up the surface? It looks like the rightmost pixels are blown out, so that's where the sunlight terminator is located. The multiple shadow-lines are caused by the mostly-linear nature of the plumes; the further ones are more "down" I guess.
-------------------- Space Enthusiast Richard Hendricks
-- "The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke Mother Nature is the final inspector of all quality. |
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Nov 15 2011, 09:54 PM
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#41
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 IMG to PNG GOD Group: Moderator Posts: 1323 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
This is a 21 frame mosaic of images obtained during Cassini's targeted flyby of Enceladus back in March 2005:
North is up and the resolution of the images I used ranges from ~35 m/pixel to ~350 m/pixel. This image is actually a by-product from a different image processing project; I should soon have a shape from shading DEM of most of this terrain. The images were reprojected to simple cylindrical projection. The resulting map was then rendered with subspacecraft latitude=-1.4 and longitude=203.8 without applying any illumination. Processed using mainly a 'mix' of ISIS, Photoshop and software written by myself. |
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Nov 16 2011, 01:02 AM
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#42
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 Senior Member Group: Moderator Posts: 2606 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
 Wow! The detail in that image is fantastic! Bravo!
-------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Nov 16 2011, 05:59 PM
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#43
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 Interplanetary Dumpster Diver Group: Moderator Posts: 4045 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
QUOTE (Bjorn Jonsson @ Nov 15 2011, 09:54 PM) This is a 21 frame mosaic of images obtained during Cassini's targeted flyby of Enceladus back in March 2005: I saw it and thought, "Oh, that's pretty." Then I zoomed in- AMAZING!!! -------------------- |
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Nov 17 2011, 01:37 AM
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#44
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 Newbie Group: Members Posts: 5 Joined: 6-August 11 From: Bariloche, Argentina Member No.: 6102 |
Amazing. Thanks for sharing it.
Guillermo -------------------- Guillermo Abramson
Leés español? Visitá mi blog! |
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Feb 8 2012, 09:19 AM
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#45
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 Senior Member Group: Members Posts: 2248 Joined: 15-January 05 From: center Italy Member No.: 150 |
Congratulations to Gordan for today's APOD mosaic, it is really stunning!
http://apod.nasa.gov/apod/ap120208.html (I would like to see more in the plume region but I guess wasn't photographed). -------------------- - Marco -
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