Crater? - And why are the Spiders not everywhere?
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by
wassock
moderator
Big crater?
https://www.dropbox.com/s/0rscrvi9q7iljfc/Screenshot_2013-03-19-22-40-18.png
Closer look
https://www.dropbox.com/s/a957bc6u0nzzrke/Screenshot_2013-03-19-22-40-03.pngIf this is a crater it is 500 meters across
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wassock
moderator
If its a 500 meter crater then would seem to me to be reasonably deep. The image is map aligned so the sun is up top, which ought to make the top side of the bottom of it be in shadow. If that is so where are the fans in the crater coming from?
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Kitharode
moderator
Bloomin' Heck. That's got everything you need to get a "yes" answer. I've had a good look at it and I've nothing to offer against the idea of crater. But we are on Mars and you know what it's like here. It's either a crater, which is interesting enough with all that spitting going on, or it's not a crater which makes it a mystery. You can't lose. Do you know where it is, how big, time of year, etc? Great find.
Is that cloud on the left? Or the edge of an icecover, or what? I'm doing ice at the moment.
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wassock
moderator
Full scale pic http://hirise-pds.lpl.arizona.edu/PDS/EXTRAS/RDR/ESP/ORB_029700_029799/ESP_029710_0980/ESP_029710_0980_RED.abrowse.jpg
Details http://hirise.lpl.arizona.edu/ESP_029710_0980
The crater is 500 meters across and features in several images . The shape of the 'fan outcrops' is consistent across the years, if not the individual fans
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wassock
moderator
The first image is from 2012, this one is 2009. http://hirise-pds.lpl.arizona.edu/PDS/EXTRAS/RDR/ESP/ORB_011400_011499/ESP_011460_0980/ESP_011460_0980_RED.abrowse.jpg
Forgetting the crater the real question may be "why are there no fans in some places and lots in others?" And why are the areas of fan formation so consistent
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wassock
moderator
2010 and the crater has a face! http://hirise-pds.lpl.arizona.edu/PDS/EXTRAS/RDR/ESP/ORB_011400_011499/ESP_011460_0980/ESP_011460_0980_RED.abrowse.jpg
NB the seas between the islands of fans do contain spiders but they seem to be switched off. Take a look at the vaguely heart shaped fan island above the crater in this image. There's another round cluster and between the 2 there is a spider. Someone must be looking at this area as there are lots of images going back to 2007. In all of them the fans are in the same areas and nothing in the areas in between especially not associated with this spider in particular. Are the fan islands higher so they get thicker ice layers?
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Kitharode
moderator
in response to wassock's comment.
Wassock. I'm gonna have a good look at these today. You raise some interesting questions. Might have something on your last sentance about fan islands being higher. First need to find where I've seen it, then see if its relevant. I'll be back later. Good thread...
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JellyMonster
Great image wassock.
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Kitharode
moderator
Yes wassock. The crater(?) is one thing, but the question you've raised is another; why fans here, not there? Can't give answer, but although I'm sure you've seen it and read it before, you might get more from a second careful read of the article below.
Haven't time yet to dig deep into article but there's loads in it. HiRise details probably useful to you. It's gonna help me place some areas on my mars map AND it talks about fan-fields and slope. Good Thread.
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wassock
moderator
in response to Kitharode's comment.
I recommend you have a shufty at the last para of section 2.1 (page 6).
There's a suggestion that the formation of spiders and their morphology is influenced by fairly small changes in slope.
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Kitharode
moderator
in response to wassock's comment.
Yeah. That slope bit stuck in my mind from first read. Also got that 'spiders form on mounds' thing to find. I think it was suggesting gently sloping raised areas, but can't remember size. Might be one mound one spider, or one big mound lots of spiders, don't know. Slopes definately in as major player though methinks.
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