Spider on the plate!
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by
p.titchin
Although not rare, it is unusual to see a well developed spider in 'Polygon Land'. ? because the CO2 is released through the plate edge fissures. Just wondered if anyone had any thoughts on why the occasional lone spider occurs. ~Pete
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by
wassock
moderator
OK my take on it is that the polygonal dark lines in the big image and the spiders are fundamentally different beasts. Spiders are eroded into the surface but the dark polygons are caused by venting along crack lines in the overlying surface and are different to the so called 'lace terrain' which is again cut into the surface. The larger HiRise image shows a number of more traditional fans, quite a few of which appear to originated from a spider....................
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Portyankina
scientist
Hi!
We can not say with complete confidence that the spider we see here is active at the present time. Most probably, it developed in slightly different climatic setting. And now it simply surviving next to more active process that creates ice polygons.
Why is it lonely is a good question. I am not sure it is that rare to find a lonely spider. The areas that you see here are mostly densely populated because we chose those areas for the reason of fans and spiders. We'd need more coverage to access how rare are lonely spiders, but as you know, we can not cover the whole polar areas with HiRISE.Anya
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by
p.titchin
Thanks Anya, my own thoughts are tending to the spiders occurring before the plates, and probably, a long time before! As I said in my opening comment, the lonely spiders are not rare, but the spiderless plates are far and away in the majority. e.g., Angi posted a good one in 'recents' last night- APF0001w5j .I'll keep my eyes open and try to get more of a feeling for this, but I suspect that we would need images from well before the HiRISE era to get an answer. Thanks again for answering, ~Pete.
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