Europa PR, A couple of new posts to the Photojournal |
Europa PR, A couple of new posts to the Photojournal |
Nov 16 2011, 07:49 PM
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#31
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
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Nov 16 2011, 08:31 PM
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#32
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Senior Member Group: Members Posts: 1591 Joined: 14-October 05 From: Vermont Member No.: 530 |
Again reminds me of sandstone over salt domes. The salt is deformable and causes some interesting chaos in the stone.
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Nov 17 2011, 01:22 AM
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#33
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Senior Member Group: Members Posts: 1591 Joined: 14-October 05 From: Vermont Member No.: 530 |
Article at NASA here links to larger versions of the Nature figures at UT:
http://science.nasa.gov/science-news/scien...1/16nov_europa/ |
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Nov 18 2011, 02:55 AM
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#34
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Member Group: Members Posts: 316 Joined: 1-October 06 Member No.: 1206 |
Okay, I have a question (it may be dealt with in the paper, I don't know)
I assume this mechanism can explain the dark staining of the chaos regions, but what about the dark staining of many of the long cycloid cracks? Doesn't this assume that there HAS been a connection between the (presumably) deep ocean and the surface at some stage in the fairly recent geological past? One that doesn't need the upwelling mantle plume/subsurface lake mechanism to communicate with the surface? Could there be regions of deep AND shallow ice? Can Jupiter's tides crack those errr cracks all the way to their ocean bases, or is there another mechanism that could bring those stains (are they tholins?) to the surface? P |
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Nov 18 2011, 02:57 AM
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#35
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
They don't mention cycloids at all in the paper -- it's a modeling paper that only deals with chaos. So the paper doesn't address that at all. I'm curious to know the answer too!
-------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Nov 18 2011, 02:58 AM
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#36
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
(Don't think they are tholins, more likely salts or other stains from water-soluble materials)
-------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Nov 18 2011, 04:00 AM
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#37
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Member Group: Members Posts: 316 Joined: 1-October 06 Member No.: 1206 |
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Nov 18 2011, 07:05 AM
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#38
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Senior Member Group: Members Posts: 2106 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Just a quick related question; how much do we know about Europa's rocky core and whether it is uneven in depth? I.e could there be places that it makes direct contact with the ice shell, without intervening water? Would an orbiter have to map it or could there be surface signs of these areas?
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Nov 18 2011, 12:03 PM
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#39
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Where would the tholins come from? Tholins form from irradiation and zapping of mixes of methane and nitrogen. If tholins are forming on Europa, it would be from zapping of small organics encapsulated in the ices as clathrates. I'm not saying it's not possible that the stains are organic molecules, but my first suspect would be salts from below. EDIT: yup, the dark stuff is consistent with hydrated sulfuric acid. See: Shirley et al. EPSC 2011, 6, (freely availalbe): http://meetingorganizer.copernicus.org/EPS...PS2011-1201.pdf and (pay for article, abstract here): Orlando et al., Icarus 177 (2005) 528-533. http://www.sciencedirect.com/science/artic...019103505001983 -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Nov 18 2011, 03:26 PM
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#40
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Member Group: Members Posts: 259 Joined: 23-January 05 From: Seattle, WA Member No.: 156 |
Just a quick related question; how much do we know about Europa's rocky core and whether it is uneven in depth? I.e could there be places that it makes direct contact with the ice shell, without intervening water? Would an orbiter have to map it or could there be surface signs of these areas? Short answer, no. Given that the estimates for the depth of Europa's ocean are about 100km, it's extremely unlikely that the rocky crust would come anywhere near the ice shell. Total relief on the moon (Earth's moon, Luna) is about 22-23km IIRC, and the moon's got a much stiffer and thicker crust since it's so cold. Since Europa's geologically active, I'd expect it to have a warmer and softer crust that wouldn't be able to support as much relief. I'd guess the highest point on the crust is ~90km below the surface of the ice. |
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Nov 18 2011, 03:38 PM
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#41
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Member Group: Members Posts: 399 Joined: 28-August 07 From: San Francisco Member No.: 3511 |
... it's extremely unlikely that the rocky crust would come anywhere near the ice shell... But how are the purported "shallow lakes" forming in the first place? -------------------- 'She drove until the wheels fell off...'
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Nov 18 2011, 03:46 PM
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#42
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
"But how are the purported "shallow lakes" forming in the first place?"
Read this for an answer: http://www.skyandtelescope.com/news/Subsur...-134059133.html There have also been suggestions that the chaos areas form over deep hot water plumes in the ocean, which in turn form over ocean floor volcanic eruptions, but modelling might not allow that. I haven't seen it tested. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Nov 29 2011, 10:16 PM
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#43
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Member Group: Members Posts: 933 Joined: 4-September 06 From: Boston Member No.: 1102 |
The Nature article is quite nice (I'm one of the lucky subscribers). Is there a chance that some of the chaos terrain on Enceladus results from the same mechanism?
floyd contact fdewhirst at forsyth dot org -------------------- |
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Nov 29 2011, 11:06 PM
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#44
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
There is nothing comparable on Enceladus. Totally different geology. There might be areas you could call chaotic if you wanted to but they are very different.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Mar 9 2013, 04:02 PM
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#45
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Member Group: Members Posts: 241 Joined: 16-May 06 From: Geneva, Switzerland Member No.: 773 |
Some new stuff from Europa:
"Based on new data from the W. M. Keck Observatory about Jupiter's moon Europa, astronomers hypothesize that chloride salts bubble up from the icy moon's global liquid ocean and reach the frozen surface where they are bombarded with sulfur from volcanoes on Jupiter's largest moon, Io." Read more at: http://phys.org/news/2013-03-astronomers-w...-ocean.html#jCp |
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