pale patch

• by sparky1977

  what are the pale patches in the middle of each fan shape?

  Posted January 9, 2013 11:01 PM

• by mschwamb scientist, translator

  Keen eyes looks like #frost . Learn more here
  Cheers,
  ~Meg

  Posted January 9, 2013 11:18 PM

• by sparky1977 in response to mschwamb's comment.

  this looks to be within the plume of gas rather than on the groung arround it, slightly different to the examples you have. Intoresting anyway!

  Posted January 10, 2013 9:21 AM

• by Judith_Williamson

  If the fans are 'plumes of gas' then they're transient...do we know if this sector of terrain regularly has 'plumes of gas' and is the 'wind' direction and speed constant?

  Posted January 10, 2013 9:48 AM

• by wassock moderator

  Jshoe - thought you'd be interested in this one

  Posted April 12, 2013 8:49 PM

• by jshoe in response to wassock's comment.

  Wassock. You bet! But I'm not sure whether anyone except iankirk, mel jones, and sparky was hinting at the "ejection" theme. Even these were treating it more like a mass ejection from a volcano that has already landed on the surface. Slightly different from my proposal that the blue material may still be airborne, more like smoke. 3 months ago I had no real concept of the consequences fine dusty matter racing through the undersurface channels and 'exploding' upward when a vent is found. I'd love to know how the particle sizes being proposed for the dust in our study compares to the fine particulates found in smoke from forest fires and industrial smokestacks here Earth, and how far each one might drift in an "average" breeze before coming to rest on the surface. Similarly, how far does fine volcanic ash drift before coming down to form similar fans here on Earth, or on a smaller body like, say, Io. In the features explained as "CO2 Frost" does the escaping CO2 contain similar fine particulates? Is this what the actual escaping CO2 streams would look like if they were all visible? Do we just happen to be able to see these special streams because they happened under the right conditions to also create this "frost"?

  I admit that I do not feel comfortable with solidifying "CO2 frost" as being the only cause of these long blue streaks. Even the science team ought to admit that is a bit of a "long shot in the dark".

  I appreciate their efforts to satisfy our questions about what we were seeing in the images that were so foreign to our eyes. And I do understand the pressures put upon them to give scientifically valid answers. They are being held accountable for explaining all this stuff to the world, I am the lucky one who gets to sit back and throw out ideas without having to back them up with rigorous proof. This is much more fun!

  But, the biggest question is "How much of this matter is still "Up in the Air"?" Am I "barking up a dead tree?"

  I still think that images APF0000r7h and 0000r65 are special and deserve a closer look. There's just something about them. jshoe

  Posted April 15, 2013 8:03 PM

• by jshoe in response to wassock's comment.

  Isn't it neat that most of the fans contain similar blue streaks?! This implies that all of these holes were leaking at the same time, under conditions appropriate for the formation of the streaks! Do they share a common ice sheet (that has built up pressure over a whole wide area that is being released all at once)? Can we map this sheet with respect to one spider alone - or does it feed several spiders at the same time?

  Posted April 15, 2013 8:11 PM

• by wassock moderator in response to jshoe's comment.

  I think that the blue is a ground feature - more on that later need to find you some pics. wrt your last post I have floated the idea that if you were to measure each individual fan, form each vent point and then do a comparison of size for each fan in each direction for each vent (with this so far?) then if the relative proportions of each fan are the same across the whole picture the the individual events must be linked in some way. Just look at 2 hypothetical vents. each has a 12 oclock and 3 oclock fan. Vent ones 12 fan is 90 metres long and the 3 60 metres long. The 2nd vent has a 12 fan 60 metres long and the 3 40 metres. If this sort of proportionality held up across the whole field for all the fans in all directions then it would be very strong evidence that the venting is linked in some way

  This could be because they are all drawing on the same reservoir of gas (which supports one theory for how the spiders work), it could be because the heat input producing the gas is the same at each point so you get the same amount of stuff proportional to the area the vent draws from (big vent big fan but proportional to energy in same as the small vent with a small fan, or just the way the wind blows and how hard. Or all 3 or none.

  From what I've read to date the fan particles are colloidal - i.e. less that a millimetre so in the same size range as common smoke.

  There are 2 obvious ways for solid CO2 to form on top of the fan material, firstly at night it could freeze out from atmosphere as the temperature drops to give a frost, secondly as the escaping gas escapes and expands adiabatically it will cool and may solidify and then fall as snow.

  Posted April 15, 2013 8:27 PM

• by wassock moderator

  There's now a fresh blog post on the issue of plumes http://blog.planetfour.org/2013/04/14/standing-on-the-surface/

  Posted April 15, 2013 8:39 PM

• by mschwamb scientist, translator in response to jshoe's comment.

  On the outside of the fans, if you see the blue, it's thought that's self-cleaning of the ice has the fan particles sink into the ice and the ice recrystallizes while the streaks is carbon dioxide frost. The streaks and the blue halos have had spectral measurements from MRO with the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars ) instrument - and they have Pommerol et al 2011 write "intermediate value of CO2 band strength between dark deposits and bright icy soil" that's one of the reasons it's though it's carbon dioxide frost on top of the fan or recrystallized carbon dioxide ice

  Thermal inertia measurements suggest the particulates in the dirt of the south pole are about 100 to 200 micrometers in size. So that's what would be the particle size of making up the fans and blotches

  ~Meg

  Posted April 16, 2013 12:26 AM

• by mschwamb scientist, translator in response to wassock's comment.

  Comparison of size for each fan in each direction for each vent (with this so far?) then if the relative proportions of each fan are the same across the whole picture the the individual events must be linked in some way. Just look at 2 hypothetical vents. each has a 12 oclock and 3 oclock fan. Vent ones 12 fan is 90 metres long and the 3 60 metres long. The 2nd vent has a 12 fan 60 metres long and the 3 40 metres. If this sort of proportionality held up across the whole field for all the fans in all directions then it would be very strong evidence that the venting is linked in some way

  That's the plan for your classifications but not for what you're saying. The fan lengths aren't coming from how powerful the geyser is, it's very likely the surface winds, particularly because we know the geysers don't go very high and the fans follow topography and the max height of the geysers ca achieve. So you would expect similar length fans in a region of a cutout because of equal wind strength. It may say the venting happened at the same time or similar timing to uplift the material perhaps.

  ~Meg

  Posted April 16, 2013 12:34 AM

• by wassock moderator in response to mschwamb's comment.

  Yurse but the horse I'm flogging is that in these multi fan multi directional fields there appears to be a commonality in the ratio of size of the individual fans at each vent. So for the simple case with 2 fans one twice the size of the other every vent in the field will have one fan twice the size of the other, but all the fan pairs will have differing sizes. The size of the fan must be down to several factors, wind speed and variability of direction, how high the plume is, how fast it comes out, how long it erupts for, particle size........ all of which boils down to wind times how much stuff comes out. But if the ratio of fan sizes at each vent remains constant then it indicates that more than just the wind is a common factor for each eruption event.

  So if the length of a fan is just down to wind speed and height of. Plume then for all the fans to be proportional then the height of all the plumes must also maintain relative proportions for each eruption event. And if they do that there is something which is common for all of them in terms of of how much stuff is erupting each time at each vent

  Posted April 17, 2013 8:03 AM