"High cloud" seen on Mars, Weather feature - or impact plume? |
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"High cloud" seen on Mars, Weather feature - or impact plume? |
 Mar 24 2012, 08:25 AM
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#1
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 The Poet Dude  Group: Moderator Posts: 5548 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60  |
Lots of speculation about the nature of a martian cloud observed by amateur astronomers...
http://exosky.net/exosky/?p=1606 Interesting. MSNBC is running the story too. Anyone seen it? Got any info? -------------------- |
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Mar 24 2012, 09:53 AM
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#2
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Member Group: Members Posts: 285 Joined: 22-September 08 From: Spain Member No.: 4350 |
-------------------- "I can easily see still in my mind’s-eye the beautiful clusters of these berries as they appeared to me..., when I came upon an undiscovered bed of them... – the rich clusters drooping in the shade there and bluing all the ground" -- Thoreau
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Mar 24 2012, 07:32 PM
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#3
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Junior Member Group: Members Posts: 81 Joined: 25-April 08 From: near New York City, NY Member No.: 4103 |
News from Sky and Telescope:
http://www.skyandtelescope.com/observing/home/143959576.html I first saw a story about this at Astro Bob: http://www.skyandtelescope.com/observing/home/143959576.html |
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Mar 25 2012, 05:19 PM
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#4
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Member Group: Members Posts: 293 Joined: 29-August 06 From: Columbia, MD Member No.: 1083 |
Those articles reference dust as a possibility, but I'd say that is probably the least likely of the choices. Particularly given the very high altitude, consistent location over the same place, and whitish color.
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Mar 28 2012, 03:40 PM
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#5
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Junior Member Group: Members Posts: 44 Joined: 16-January 06 Member No.: 646 |
Dust is very unlikely given that the feature does not persist all day, and the increasing visibility into the blue. The single scattering albedo of water ice is essentially 1 through the optical regime, while airborne dust follows the properties of the surface (more or less in terms of albedo). See the attached MRO/MARCI "daily global" normalized-radiance maps in Band 7 (330 nm): March 20 and 21 (UT). These maps are "quick and dirty" and more importantly, represent the the local time of ~14h-16h30 across each strip (at least away from the polar regions).
If the feature was caused by dust, there would have to be a lot of it (from a light-scattering perspective), and it would be expected to be present in the afternoon (i.e., attached maps; though the location of the feature is inconveniently split across the boundaries of the cylindrical projection used). What makes the feature interesting to me is its southern extent, particularly with respect to the so-called aphelion cloud belt.
Attached thumbnail(s)
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Mar 29 2012, 02:04 PM
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#6
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Junior Member Group: Members Posts: 60 Joined: 20-March 10 From: Western Australia Member No.: 5275 |
Surely we are directing some big eyes at this feature? Hubble time, as well as the orbiters should make this event a priority item.
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Mar 31 2012, 11:42 AM
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#7
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Member Group: Members Posts: 293 Joined: 29-August 06 From: Columbia, MD Member No.: 1083 |
High altitude water ice cloud seems to be the working consensus.
http://cosmiclog.msnbc.msn.com/_news/2012/...cloud-explained |
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Mar 31 2012, 04:09 PM
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#8
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 Senior Member Group: Admin Posts: 4732 Joined: 15-March 05 From: Sloughhouse, CA Member No.: 197 |
In the last paragraph Alan Boyle sends people to UMSF for more information. Nice.
-------------------- If Occam had heard my theory, things would be very different now.
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