Sol 22 and after, Digging in Wonderland |
Sol 22 and after, Digging in Wonderland |
Jul 29 2008, 03:57 PM
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#346
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Senior Member Group: Members Posts: 4252 Joined: 17-January 05 Member No.: 152 |
Thanks for the colour frame, Stu. I'm impressed with the absolute positioning accuracy for the arm: They've put the new set of (16?) rasp holes almost perfectly between the first set of 16. That's sub-centimetre accuracy! Teck - I've been watching and the sublimation rate at Dodo/Goldilocks has dramatically slowed from the early sols. Perhaps it's reaching an equilibrium, with sublimation matching frost depostion? |
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Jul 29 2008, 05:47 PM
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#347
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Director of Galilean Photography Group: Members Posts: 896 Joined: 15-July 04 From: Austin, TX Member No.: 93 |
Do you want some sublimation? Heck, you don't need an animated GIF, that last image clearly shows that the icy parts are deeper now than the non-icy. Check out the shadowing along the edge. -------------------- 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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Jul 30 2008, 02:01 AM
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#348
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Senior Member Group: Members Posts: 4252 Joined: 17-January 05 Member No.: 152 |
Here's two comparison blinks of Snow Queen, sol 21 - 44 taken from slightly different positions and angles... Some of the changes are clearly real like the moving sand grains... The rest are less clear...cracks, trails of rolling particles, or shadows?: Snow Queen A Snow Queen B Well, this is pretty old news for us folk, but in this new update they discuss the changes between sols 21 and 44: QUOTE Cracks as long as 10 centimeters, or about four inches, have appeared. A seven-millimeter (less than one-third inch) pebble or clod not seen there before has popped up on the surface. And some smooth texture on Snow Queen has subtly roughened. I'm a bit surprized by the cracks claim - my best guess was tracks left by pebbles - we can see some have moved between the frames. |
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Jul 30 2008, 02:22 AM
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#349
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Meanwhile, over in 2D land, poor Snow White is looking really battered now... Sure is, and if my hypothesis is valid then so will every other dig in this area over time. Hmm. Going out on a limb here. The North Polar region (Vastias Borealis) is very smooth and quite broad in terms of surface area, while the South Polar region really isn't, except at very high latitudes, and even then it ain't the same. Impact cratering rates would presumably be statistically equal for both regions. There does seem to be a mechanism for autosmoothing of terrain in the north, namely subsurface ice exposure/sublimation/mass repositioning. Does this mean that subsurface water ice is preferentially concentrated in the North Polar region....and, if so, why? I understand that the Southern Hemisphere is orographically higher than the north, but does a difference of just a few millibars of atmospheric pressure at most make that much of a difference in the behavior of ice sublimation/deposition? The hemispheric dichotomy is puzzling, even considering surface topography. Is there a similar dichotomy in crustal composition between the poles? -------------------- 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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Jul 30 2008, 04:31 AM
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#350
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
I'll add another question: how much mass transfer of moisture is there between the poles?
Does Mars have a global circulation or could the water be hemispherically locked somehow? (i.e. The North has it's water vapor, the South has it's water vapor, and never the two shall mix) -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Jul 30 2008, 06:33 AM
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#351
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
Good question! If I had to guess...we have a planet that evaporates/sublimes CO2 ice and H2O ice at the summer pole, and condenses/freezes those molecules at the winter pole. The atmospheric pressure is well below the partial pressures of those vaporizing reservoirs. Am I over-simplifying the cycle? I am guessing (with fingers crossed), that the poles exchange condensibles.
We've had discussions here regarding frost. I don't have much to say about that, but I did notice the word "frost" appear in association with some sol 60 SSI images. They were described as "SSI Frost Spot of Snow White16AB," "SSI Frost Spot of Winkies & Quadlings16AC," and ""SSI Frost Spot of Nightengale16AD." There were RGB filters available for these 3 "target" images. Here are the raw jpg RGB composites, with no subjective color balancing applied. Snow White Winkies & Quadlings Nightengale -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Jul 30 2008, 07:56 AM
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#352
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
I think the scales are so utterly different as to bear no relationship:
The smooth/rough impression comes from MOLA maps, which emphasize difference on the scale of hundreds of meters or more. The soil overlying the ice is centimeters -- we're talking about several orders of magnitude difference. My take is that the smooth/rough difference between the poles is about a single catastrophic flow event that buried the lower elevations planet-wide in slurry and paved over the cratered highlands. The subsurface ice at these latitudes is probably something that would seep back in in a whisper of geological time if you removed it and let it emplace itself anew, but not on a scale to erase massive craters and canyons in the ancient highlands. |
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Jul 30 2008, 10:35 AM
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#353
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Rover Driver Group: Members Posts: 1015 Joined: 4-March 04 Member No.: 47 |
"I'll add another question: how much mass transfer of moisture is there between the poles?
Does Mars have a global circulation or could the water be hemispherically locked somehow? (i.e. The North has it's water vapor, the South has it's water vapor, and never the two shall mix)" According to Read and Lewis (The Martian Climate Revisited) there is a net transport of water from the north to the south. During northern summer some of the water ice of the cap melts and gets into the atmosphere as vapour. this then gets transported to the south where it freezes onto the polar cap. During southern summer water ice in the southern cap does not get exposed (the south is much higher) and so there's not so much water vapour coming back. But these kinds of theories can change with more data. |
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Jul 30 2008, 05:53 PM
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#354
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Member Group: Members Posts: 252 Joined: 5-May 05 From: Mississippi (USA) Member No.: 379 |
Reminder
Phoenix News Conference Tomorrow: July 31, Thursday 2 p.m. EDT = 6 p.m. GMT/UTC According to the NASA TV web site - it's still on NASA TV Schedule July 31, Thursday 2 p.m. - Phoenix Mars Lander News Conference - Tucson/JPL (Public and Media Channels) Jack |
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Jul 30 2008, 06:33 PM
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#355
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
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Jul 31 2008, 04:56 PM
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#356
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
Seems like it's time for a new thread; carry on with the discussion over here
http://www.unmannedspaceflight.com/index.php?showtopic=5359 --Emily -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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