Planet Four Talk

Fans-repeating patterns...

  • Paul_Johnson by Paul_Johnson

    Having observed many hundreds of these bad boys...fans do seem to have a common theme, and I like repeating patterns!

    Many are 'V' shaped, which I assume is that they have erupted twice with different wind directions, creating a V. If that is so, how come many fans together have the same directions of material....they must have erupted at the same time-twice. Is that true? if it is then it is cool! The material on one side of the 'V' is often shorter than the other side-why? The jet must have been weaker, then on the second eruption stronger-or vice versa-why? Also, forgive me if I am boring you by now....one side is often darker than the other-is this indicative of time, the darker the material, the fresher? Hundreds of the mulitple fan pictures demonstrate this, some don't, but many do...

    If the fans in a fanfield erupt at the same time (which they seem to do because of the common wind direction) twice-to create a 'V' it must befor a reason, any guesses? I was wondering if CO2 ice has a refractive index that means the sun is particularly strong at 2 simiar angles throughout a Martain day, hence causing 2 eruptions by the gas beneath....? Wild, I know....but that is as far as I got with trying to explain a 2 eruption fan theory!

    Posted

  • Paul_Johnson by Paul_Johnson

    APF0000asf
    APF0000q27
    Here's a couple to see what I mean....

    Posted

  • Paul_Johnson by Paul_Johnson

    Just waiting for everything I just said to be blown apart.........wait for it.....

    Posted

  • Ian_Mason by Ian_Mason

    Hi Paul,

    I think wind might be the crucial factor here, & it an indication on how it has veered. I wonder if Mars has similar colder/milder winds similar to here on Earth, & whether that & the sunlight control when these things go off & perhaps freeze over again?

    enter image description here

    Posted

  • Paul_Johnson by Paul_Johnson

    That's it exactly. My met training (it's been a while) reminds me that on earth the wind follows a simiar pattern every day, veering/backing (i can't remember which) through the daily cycle. Also,colder, denser air would affect the distance material would be thrown....hmmmm.

    We're onto something here...!

    Posted

  • Paul_Johnson by Paul_Johnson

    ....wait for it......here comes a scientist..........

    Posted

  • Hakaeh by Hakaeh in response to Paul Johnson's comment.

    No- it's only me. 😃

    Have posted this earlier, thinking it is interesting as it allows for hypothesis about wind direction/strength and the way matter is thrown or frost is forming..

    http://talk.planetfour.org/#/boards/BPF0000002/discussions/DPF00007mo

    Image APF0000pms

    Posted

  • Paul_Johnson by Paul_Johnson

    H, you are spot on, these fans tell a great deal about wind. Do you agree that many seem to be in 2 stages? That where there are muliple similar fans then there must be a common cause of eruption and that they must go at very similar times. What's your view?

    Posted

  • Paul_Johnson by Paul_Johnson in response to Hakaeh's comment.

    ...and yes, I thought you were a SCIENTIST, come to get me.......

    Posted

  • wassock by wassock moderator

    the right most fan has 3 lobes to it and there's just about a third plume visible (maybe) in Fan to the left of that one. Up and left from there is a single, fatter, fan which looks to have the same direction as the minor features in the other 2.
    T the point about multiple fans is interesting, particularly in the large fan fields where all the fans are bidirectional and presumably extend over a larger area than can be seen in one image. It would make sense that multiple fans showing the same evidence of separate emission events with wind directions for all being the same indicates an effect which forces gas to the surface over a large area.

    Posted

  • Paul_Johnson by Paul_Johnson

    Kerching! But that's astonishing-they all go up together, stop, then go again - together, with a different wind direction. Then stop.

    Come on-that's very interesting to me!

    Posted

  • Paul_Johnson by Paul_Johnson

    The gas must be uniformly pressurised, then along comes the sun, gas expands, boom, they all go together.

    Posted

  • Hakaeh by Hakaeh

    Yes Paul,
    I believe some fans even show 3 different directions/times of expulsion, if I find a suitable example I'll post it here. but assuming there are so many factors determining shape, size and colour of the fans:

    1. there is the wind and its attributes: temperature, speed, direction (you probably know better about this being trained-got ya!)
    2. size of the gap or hole
    3. the matter being dispersed
    4. the pressure behind the matter

    Also, I think the winds that have shaped most fans would be very strong?

    no idea why the emission happens wassock, it was mentioned a few times by the scientists.

    I wish I was a scientist

    Posted

  • Paul_Johnson by Paul_Johnson in response to Hakaeh's comment.

    Hakaesh, I simply can't explain what is going on with that picture-how can the material end up like that?

    Is it being affected by the fans next to it?

    Posted

  • Hakaeh by Hakaeh in response to Paul Johnson's comment.

    do you mean in general or in this pic : Image APF0000pms

    i think this pic shows that the big ones have gone off two (or three) times and the little one only once (maybe twice) which should mean that either the big ones came up first (black and frost and then black again) and then the little one (black only) or the other way around. if the little one came up earlier, maybe not so much CO2 in there, or it was forced up later due to the pressure release adjacent....oh and then there is the wind.. changed from not so strong (wider, shorter fan) to quite strong (longer, narrower fan). OR that is due to the change in pressure... Oh- I don't know! Help!

    Posted

  • Kitharode by Kitharode moderator

    Keep going you guys. You've got a terrific thread going here. I'm intrigued (and impressed) by your questions and your efforts to find answers.

    Posted

  • Hakaeh by Hakaeh

    Found it!

    Image APF0000b00
    shows 3 or even more wind directions (or events of expulsion)

    Posted

  • Paul_Johnson by Paul_Johnson

    ....yes, but.....the ones with blue elemnts do seem to have 3 phases.....I could be wrong! I find they seem to have 3 phases, often with the blue element in the middle. I've been thinking...(I know, I know....) Would the katabatic wind (cold air rushing downward-very strong!) have an effect on this....? If the katabatic is a very shallow depth, it would take lighter materials before they could go far into the normal wind, they would travel in a different direction? Heavier materials would go further, having more ooomph and make it into the normal flow of wind?

    Me brain hurts!

    Posted

  • Paul_Johnson by Paul_Johnson

    The heavier materials would make it to a different place, as seen by the evidence....

    Posted

  • Hakaeh by Hakaeh in response to Paul Johnson's comment.

    If the white is the same as the blue (frost) then it's not always as you said, like here: Image APF0000wpt or here: Image APF0000wnt ?

    Posted

  • Paul_Johnson by Paul_Johnson

    I was thinking, the only thing that has a twice daily effect on earth is the moon. Would the 2 moons of Mars exert any diurnal effect on the ground ice and gas, heating it up and causing the gas to blow? I think not, they are comparatively small-just pondering.....

    Posted

  • Hakaeh by Hakaeh

    i think the frost comes out first, then the black deposits

    Posted

  • Paul_Johnson by Paul_Johnson

    Yes, I see what you mean, H. Blue streaks confuse the issue! They seem to have a different dynamic.

    Posted

  • Hakaeh by Hakaeh

    interesting thought (moons)! sth like an underground gaseous tide!! ok, better stop here..

    Posted

  • Paul_Johnson by Paul_Johnson

    Cheers H. Happy hunting.

    Posted

  • Hakaeh by Hakaeh

    ok edit my own post: frost not always first as seen here (the white fan overlying the black fan)
    Image APF0000wxu
    maybe its just the order of deposit or due to pressue/temperature that determines when frost is blown out as a fan

    Posted

  • Paul_Johnson by Paul_Johnson

    Perhaps it is temperature dependant? The colour of the CO2 crystals depends on the temp....?

    Posted

  • Hakaeh by Hakaeh

    yes that's it! i wish there was a comment from the professionals..

    Posted

  • Kitharode by Kitharode moderator

    Oh No ... Don't stop now. I was really enjoying that.

    Posted

  • Paul_Johnson by Paul_Johnson

    I'm supposed to be writing an English Lit essay!

    Posted

  • Kitharode by Kitharode moderator in response to Hakaeh's comment.

    Are you sure the frost is 'blown out'?

    Posted

  • Paul_Johnson by Paul_Johnson

    No! It could form on the gas crystals that have been deposited, as an after event....?

    Or it could already be on the material already and become white when exposed to the martian air/cold.

    Posted

  • Paul_Johnson by Paul_Johnson

    It does seem to travel further than other materials....do you think-white plumes are normally big plumes.....why?

    Posted

  • Hakaeh by Hakaeh in response to Paul Johnson's comment.

    no i dont think so, too many pictures showing different like this one Image APF0000b00

    but i do think the frost is "blown out" just like the darker material, as they are the same fan like shape

    Posted

  • Paul_Johnson by Paul_Johnson

    White seems to go further....

    APF0000ptn

    APF0000q27

    Posted

  • Paul_Johnson by Paul_Johnson

    To get back to the original thread.....this represents a pattern, where some types of fans seem to follow the same course..

    They seem to go off at the same time. They throw their material the same way and they explode quite often, often twice-and in different directions.

    I like that, it means something......just hope some of our ideas here are on the right path.....

    Posted

  • Hakaeh by Hakaeh

    in most cases it seems to go further..

    just adding another interesting one: Image APF00009gt

    Posted

  • Hakaeh by Hakaeh

    Paul, how's the essay going! =]

    Posted

  • Paul_Johnson by Paul_Johnson

    hahaha! I give up on it. Tomorrow I will ddicate myself to it, after work of course!

    Posted

  • Hakaeh by Hakaeh

    blimey u are busy. don't forget to think about fans in between

    Posted

  • Paul_Johnson by Paul_Johnson

    I think the white stuff is a chemical reaction between the material thrown up and the surface chemicals. There! Boom.

    I think it appears when the conditions are just right, chemically / temperaturely (?) and perhaps depending on the differntial between pressures below and above ground-which also may be affected by the width of the apperture of the hole it comes through....

    Boom.

    Posted

  • Paul_Johnson by Paul_Johnson

    If you ever shot a CO2 fire extinguisher, you will notice some of it comes out as ice crystals, as well as the gas.......interesting....hmmmm!

    Posted

  • Hakaeh by Hakaeh

    it is hard to stop! =]
    never got to putting a fire out. there is something up with the white stuf aka frost. and i am beginning to think it is different from the blue stuff.

    Posted

  • Kitharode by Kitharode moderator in response to Paul Johnson's comment.

    I think I have a preference for the 'reaction after the event idea' for frost fans, rather than the blown-out idea. Re your original thread, yes there's a pattern and yes it's interesting. I think yes also to some of your ideas being on the right track.

    What are your thoughts on "at the same time"? All 'boom' within an hour, on the same day, in the same week ... ? These events are seasonal, so a 'chain reaction' of fans could possibly occur over an extended period. It would be useful to know if wind patterns are generally long or short (if you see what I mean).

    Posted

  • Paul_Johnson by Paul_Johnson

    Kitharode, well.......I think they go more or less at the same time, beacuse the general area is evenly pressurised (my assumption based on the fact that many areas seem to be made up of uniform material-the pressures of gas would be failly even). The sun comes up, gas expands, boom. Don't get caiught peering down a blow hole......or taking a......well anyway. The pressure is released but maybe the hole is blocked with material-then the pressure builds again, boom. The sun goes down. The material sinks back through the ice and the whole cycle starts again. During this the wind changes direction, which it does evr so slightly back here on earth, resulting in a uniformity of two, sometimes three fan directions. The fans all have similar appearances because the same materials, same gases and similar wind actions work upon them. I think there is then some time (really guessing now) before the build up of gas is enough to set off the cycle again, otherwise there would be lots and lots of ghost fans, and I have seen only a few. They are all rather fresh is what I'm trying to say. So I dont think it happens daily.....

    What do you think?

    Posted

  • Paul_Johnson by Paul_Johnson

    I woulld be interested in knowing the strength of wind near the surface (on earth it is slower near the surface) and on Mars? The wind is katabatic-really cold (so denser) and fast-travelling down hill from the pole (just as on earth), so may well be a fearce cold wind at the surface-with a relatively warmer gentle breeze, almost balmy you might say, higher up.

    Posted

  • Kitharode by Kitharode moderator

    What do I think?

    I think you've got your teeth into something and you should keep biting. I think you should keep musing and rambling, and being silly on occasion. I also, in all honesty, think you have the basis for an interesting and plausable theory.

    Have you considered building a collection of images, so that you can subclassify by, for example, types of terrain, ratio of black to blue in plumes, or whatever? This is what I'm doing with my 'Linear Emmissions Structures'. Very informative.

    Posted

  • Paul_Johnson by Paul_Johnson

    I may do that, next week-after my English Lit essay has gone away!

    Good luck with your work and thanks for the encouragement, Kitharode. It's been a pleasant diversion.....

    Posted

  • Kitharode by Kitharode moderator

    Good luck with the essay. Hope you pick up here again. Cheers for now.....

    Posted

  • wassock by wassock moderator

    I think that it is significant that the 'lobes' in the heart shaped fans are in proportion across all the fans in the local group - so if you have a uneven heart shaped fan with 2 lobes, the small side will be on the same side across all the fans and the relative proportions of the two are the same in all the fans. Just an impression I've got from those I've looked at, will need to collect a few and see if it works.

    Posted

  • Paul_Johnson by Paul_Johnson

    Thats the spirit, wassock!

    I'm a big fan of these features!

    How can that be though? It seems to be well, illogical for that to happen, from holes that are seperate. All the holes blow out a repeating pattern-why should that happen? Truly amazing that we are even discussing this, great stuff!

    Posted

  • wassock by wassock moderator

    If it's real then it must, I think, mean that all the fans are tapping the same gas reserve. Big bubble of gas under the ice with various size holes tapping into it. When conditions are right all the holes pop at the same time and the bigger holes make bigger fans, simples. Next time the system pops the amount of gas is greater or smaller than the first time and you get bigger or smaller fans but the size of an individual one is the product of gas pressure and size of the hole so the relative proportions of each fan cw all the others stays the same. The odd fans that exist in some fans or not others are then the product of times when the system is not completely connected, maybe at the start and end of geyser season.

    Posted

  • Paul_Johnson by Paul_Johnson

    I was thinking of this earlier, a common source, but I just couldnt imagine underground caves filled with gas, beneath the surface.....Surely the fans would soon be big craters with such a large volume pushing up and out-? Maybe not, maybe maybe.....maybe the gas perculates from caves deep below, whith rocks and minerals above, supporting them.....I like it wassock-you are thinking deep man, thinking deep.....!

    Posted

  • Paul_Johnson by Paul_Johnson

    It would be interesting to know how deep the ice is and the properties of CO2 ice and gas at these temperatures, but not a scientist in sight tonight.....ask a bone question about 'is this a mountain range with orange jellyfish on it' and they are there like a flash......

    Have a proper discussion, ...................(silence).........

    Oh, there I go again, me and my conspiracy theories.....tchh.

    Posted

  • Paul_Johnson by Paul_Johnson

    The caves woulld have to be constantly regenerated. Otherwise, no build up and boom.....

    Perhaps the weight of ice and material is squeezing on top of a softer layer below, perhaps this happens when ice forms, and the weight of the ice squashes the gas out of the ground into caves and hollows......hmmmmmm

    Posted

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

    Common sources, bubbles, 'reservoirs', relative proportions, ... This is good stuff, guys. So with regard to the original question (what was that?), what do you know, what have you 'discovered', what do you need to know?

    Posted

  • Paul_Johnson by Paul_Johnson

    I know there are commonalities in the fans that suggest all the things we have discussed, similar patterns across fanfields etc....we have discovered I am not so keen to write Eng Lit as I am to discuss this stuff, which will come back to bite me....I need to know how CO2 ice works at these temperatures, as well as gas. I would love to know the speed of winds near to the surface and above, to see if this is a factor in pattern formation-and also if CO2 gas acts /looks differently at low temperatures. Finally, does the martian surface rise and fall with the weight of ice (like it does on earth) and could this squeeze gas into pressurized pockets/caves, as suggested by wassock?

    Apart from that, not much really!

    Posted

  • Paul_Johnson by Paul_Johnson

    I just read that back, could the weight of the ice cause the jets, by squeezing the ground below?

    Hmmmmmm....

    Posted

  • Paul_Johnson by Paul_Johnson

    Kitharode, are you a scientist? You ask good questions....!

    Posted

  • Paul_Johnson by Paul_Johnson

    Naaaaa, forget it, the ice isn't thick enough to squash much at all. Not a strong theory, that one!

    I think a few metres thick, if that?

    Posted

  • Paul_Johnson by Paul_Johnson

    I suppose if you put a two metre thick layer of ice on a swamp, lots of gas would try to get out, especially if it was super cold but being warmed up through a clear sheen of CO2 ice. But Mars aint a bog, the layer underneath is probably rocks and martian 'soil' so I don't think gas would be especially prone to being squeezed so hard. Forget it, it's unlikely!

    Where does the gas come from anyway?

    hmmm.....

    Posted

  • wassock by wassock moderator

    OK folks, I knew I'd regret "bubble" soon as I hit submit - all we need is an interconnected reservoir (don't start picturing a huge expanse of water behind a dam) of gas under the ice. And we are talking about very low pressures here, a metre of (water) ice could hold in a reasonable amount of pressure above atmospheric here on earth, the pressures we are talking about here are a small fraction of that, so I don't think we need to worry about blowing the whole surface away. Kitharode, the original question is "why do some fans have discrete elements pointing in different directions" . Paul The earth or bits of it like East Anglia rise, and fall, due to the effects of a couple of miles of ice so don't think that ice compression onto what is probably already permafrost is much of an issue either. What we do need is either a mechanism for sealing up all the holes so that pressure can build up again or a way to generate lots of gas quickly

    Posted

  • Kitharode by Kitharode moderator in response to Paul Johnson's comment.

    Thanks for the compliment. I'm not happy to call myself a scientist. I scraped (just) a BSc in environmental science 15 or more years ago. I know a lot about astronomy (my late wife was an astronomer) and I have taught the subject, at low level.

    I'm actually a musician, or perhaps musical academic might be closer to the truth. I'm getting too old to play!!
    In case you're interested, my website is: http://ancientgreekmusicalnotation.co.uk/

    I'm trying to ask the 'right' questions at the right time to keep you going. You're doing a great job - just keep doing it...

    Posted

  • Paul_Johnson by Paul_Johnson

    Boooom! It's a 'wassock' hole! lol

    Maybe the ice is blown over the holes, the wind is probably colder than normal temps, wind chill etc.....ice is also, well, elasticy, no? It flows and stretches, like in a glacier. That could plug a leak, maybe.

    As for gas, perhaps mars soil is just full of it, heat it up and boom? Perhaps the ice interacts with the martain surface to produce a chemical response of CO2 build up. More sunny days, more gas......weakness in ice, boom. We did discuss earlier that the surface seems to turn the material ejected white and frosty-perhaps this happens at the interface between soil and ice to give of gas???

    Me go to bed now.....work tomorrow!

    Great discussion team!

    Speak soon.

    Posted

  • Paul_Johnson by Paul_Johnson

    Kitharode....you are doing a good job.

    Tomorrow, 'Elements of Greek Music Notation' !!!! Now that's a challenge, right there!

    Speak tomorrow my friend.

    Posted

  • Portyankina by Portyankina scientist

    Hi everybody!

    The topic starter: I like a lot your analysis. Basicaly, that's what I think as well, when I see these double fans. We started this project to find out if all the feelings we got were statistically right or not. Seeing 100s of images and saying "I feel like most of them have V-shaped fans" is much weaker statement than saying "people marked 100 fans, out of those 100 this many (put number here at the end of this project) had 2 fans starting at the same source".
    One very possible explanation for V-shapes is that the wind direction in each location "drifts" during spring. So, first fan is from eruption early in spring and second - a bit later but when wind has already shifted.
    Another explanation is that it's diurnal variation of winds. First fan came in the morning, second fan came in afternoon... To distinguish we need to see how large time intervals between 1 and 2 fan. Maybe we can do that if we have enough time resolution in the places with double fans.

    Just a little example for you for what we are hoping to get out of this project. There are much more, I hope!

    Anya

    Posted

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

    Anya, any thoughts about the proportionality of the different fans in a group indicating that they are all linked?

    Posted

  • Portyankina by Portyankina scientist in response to wassock's comment.

    Not much apart from one: we know that most of fans formed in early spring become brighter with time, so their apparent size decreases. But if the fan was created in second half of spring - it never shrinks. So, I think, all proportions will depend on timing of images.

    Anya

    Posted

  • Kitharode by Kitharode moderator

    Thanks Anya. Paul will be thrilled to see you here when he gets back tomorrow.

    I get the feeling that Paul and Wassock (and myself) would appreciate it very much if one of the science team, or all of the science team, could filter through some of the comments and say "no, can't happen because..." or "good point, follow this idea..." etc.

    I understand that part of this project is aimed at finding out about wind speed, so you can't be specific about that obviously. But are there any ballpark figures or general estimates available that we could use in this discussion. Many thanks.

    Posted

  • Portyankina by Portyankina scientist in response to Kitharode's comment.

    I'll try to read through your discussion, when I'll get more time than 10 mins, ok? You guys wrote a lot! 😃

    Anya

    Posted

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

    Thats not quite what I meant - have a look at my 2 posts previous to your first one tonight. How long do you think it takes for the wind to change? I understood that its thought that the actual venting is a fairly short lived event so where I'm going is that all the fans in one of the large groups of similar fans form at more or less the same time and that if it holds that the ratio of relative lobes in each fan implies a common source for all of them

    Posted

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

    Anya thats not quite what I meant, you probably need to read through the whole thing and particularly my last 2 posts before you came in to see where I'm coming from.

    Posted

  • Portyankina by Portyankina scientist in response to wassock's comment.

    Ah, I see.

    I agree with this: "mechanism for sealing up all the holes so that pressure can build up again or a way to generate lots of gas quickly" - and both are theoretically possible in these areas. The ice layer here is dry ice, it has a meta-morphing properties, so it tends to "heal" cracks fast if its temperature is slightly increased. And production of CO2 gas underneath of this ice is also rather efficient, because the ice it close to sublimation temperature (otherwise, if the ice would be colder the atmosphere that is made from 95% CO2 would completely collapse to the polar areas) This means, you need to warm it up only a bit to get the sublimation started. The source of the energy is debated, but solid-state green house is the favorite in the debate.
    Than again, it's not like we know that all the fans have to form during 1 hour or a day. Maybe they during couple of weeks is reasonable time interval? I am not ready to pin it till I get the statistics. With that interval "simultaneous" jets are not unimaginable, right?
    Anya

    Posted

  • Kitharode by Kitharode moderator

    wassock, please could you clarify your idea of 'ratio of relative lobes'. I've forgotten the 'what to what' attributes discussed earlier.

    Posted

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

    Whoops, thought the first of these had vanished into the ether, sorry for the rep

    Posted

  • Portyankina by Portyankina scientist in response to wassock's comment.

    Corrections:

    • but sun plus solid-state green house is the favorite in the debate
      Maybe couple of weeks is a reasonable time interval?

    I'm trying to type faster than I think... sorry

    Anya

    Posted

  • Kitharode by Kitharode moderator

    Many thanks Anya. We all know how busy you must be, so thanks for squeezing us in 😉

    Posted

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

    Ratio of lobes runs thus. My feeling is that in a field of v shape fans of varying sizes the ratio of the size of the 2 lobes is the same for all the fans in a group. So if fan A has 2 lobes 1 100 meters long and the other 70 meters long then the smaller one next door will have (say) lobes 50 and 35 meters long, and so on. If this holds true then it can be explianed by them all erupting at the same time from a common gas source

    Posted

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

    Anya,care to elaborate on "solid state greenhouse"?

    Posted

  • Portyankina by Portyankina scientist

    You might be right with "ratio of lobes" - we will see this from stats - but I am missing the connection to the common gas source. If you imaging that underneath each fan is a separate cavity and they all get same amount of energy for eruption, proportionality will stay, no? And in the opposite, if you imaging huge cavity underneath all the area of fans, you'd need to have same conditions everywhere - like for example, thickness of ice layer must be uniform, pressure must be re-distributed somehow not that larger holes eat up all the gas and so on. M?

    Solid state green house is like atmospheric green house but instead of atmosphere you get some solid. In our case it's ice layer. Sunlight of visible wavelength gets thought this layer and at the bottom of it it warms up the substrate, i.e. shifts in wavelength to thermal. Thermal radiation can not get out through the ice layer - and has to contribute to the sublimation. You can try to google it for more details.

    Anya

    Posted

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

    An excellent response - I totally get it. So, how do we find out if this holds true? How's about making up a collection and doing some measuring? I'd be happy to get involved to help find an answer. If you wanna play, why not get a few images together so that I can see precisely what type of objects are most interesting/useful. Then we could all measure and compare. Over to you.....

    Posted

  • Kitharode by Kitharode moderator in response to Portyankina's comment.

    Oooh this is good stuff. More when you have it, please. What do you think about my plan to preempt your stats and find the 'ratio of lobes' (what a great name) all by ourselves?

    Posted

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

    OK this is where it all probably falls apart. I'm thinking that the size of the fan is a product of gas pressure and size of the hole it comes out of. So if the hole far a particular fan is the same size for each eruption then a different size fan means the gas pressure is different (or the duration is different which should be the same thing). So if we have several fans erupting twice at the same times (as evidenced by direction) and the relative sizes of the lobes is the same for each fan then the gas pressure at each vent must be the same for a given eruption and the easiest waay to arrange that is to link all the vents.

    Posted

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

    Just how transparent is the ice? I keep picturing it as dry ice which I guess is like comparing a snowball to a lump of ice in my drink.

    Posted

  • Portyankina by Portyankina scientist

    Kitharode: If you have enough time to do it, why not? Just keep in mind that you need to do it for different areas to state something about the mechanism.

    Wassock: I agree with the most of your description, apart from 3 points: 1) you still have to seal the holes otherwise you can not build up the pressure. So why would the new holes be the same size as for the first eruptions? There is a possibility that the process is constant out-gassing... I did not think this through yet. 2) I disagree that "the easiest way is to link all vents". Considering the topography of this places with all the channels and bumps. The easiest way is to think that size of lobe (i.e. gas pressure in assumption of keeping vent hole the same between eruptions) is proportional to the energy input per area. So if one fan is feeding on 1 m^2 the cavity which is 1m^3 and another one is feeding from 2m^2 the cavity of 2m^3 - the proportionality in created gas pressures will be conserved with changing energy input per are... Hope you are getting this... I am not sure I explain it clear enough. 3) the strength of the wind is something you do not consider yet. The length of fan will be largely dependent on it, maybe more than on any other parameter.

    The transparency of dry ice depends on its structure: if it's in slab form (same form of ice as water ice on frozen lakes) - the transparency is about 70% for 1m thiknes. If it's frost - much less.

    Posted

  • AUricle by AUricle in response to wassock's comment.

    This is an excellent discussion.
    @Wassock,
    I think that there are two other parameters which haven't been considered yet.
    1)Wind speed.
    2)Elevation of the terrain immediately down-wind from the 'vent', both which may determine the lateral 'spread of the fan, and its eventual 'length'. Submitted for consideration....

    Posted

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

    I was ignoring the wind speed because I'm only looking at the comparitive sizes of fans close together, so 2 fans pointing the same way are made at the same time with the same windspeed so any difference in size must be down to the amount of gas and the height of the plume. More to come - school run time......

    Posted

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

    I'm taking it as read that either the holes seal or there's a way of making gas fast (which doesn't happen every day) to explain the multi directional fans. If there's continual outgassing I think you'd get a feature like the very dark fat fans - the stuff just keeps coming and the edges of the fan give you the vectors for the extremes of wind direction with wind speed staying fairly constant for the duration. some of these fans have longer bits poking out, so either the wind got a bit stronger for a while or there was more gas for a bit. The holes seal, but they're not gonna go back to being a metre thick so I think it's likely that next time they blow the hole/fissure/whatever will be about the same size, and I need that for my theory of linked holes to hang together. If we go with your way of looking at it discrete gas supplies beneath each hole, but all subject to the same process for sublimation then we don't need to link them as the amount of material is just dependant on the amount of gas beneath each hole. If the length of time between eruptions varies then maybe the amount of gas that has built up will vary too and that would explain the different size lobes and any proportionality between the different sources which may (or may not) exist.

    Posted

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

    I'm gonna change tack slightly so thought I'd start anew. Do you need the spiders and channels to generate a reservoir of gas beneath the Ice? The emerging gas has dust in it which settles on the ice and then deposits back to the ground when the ice melts ergo the surface is dusty. So when the bottom layer of the ice warms up so will the dust beneath it and the gas can penetrate this to give a thin layer of gas/dust over a wide area of surface. Gas on its own would not be anywhere near as abrasive as a suspension of sand, and 'sand blasting' would be an effective way of carving the surface. So maybe we need to look at some sort of fluid bed of gas/particulate beneath the ice rather than a void filled with CO2.

    Posted

  • Hakaeh by Hakaeh

    read through your discussion last night and thought about the plugging of the holes: maybe the white stuff is the plug which has been thrown up?

    Posted

  • Hakaeh by Hakaeh

    and if the white stuff is the same as the blue, it comes out of spider troughs too Image APF0000m5q

    Posted

  • Kitharode by Kitharode moderator

    Hi there y'all. Re solid state greehouse, I'm told that 'the thermal properties of the underlying lithosphere are important'. How important I don't know (the articles are very complex - yawn). I've just started digging around for potentially useful info on Mars lithosphere, on the off-chance that something turns up. Or maybe you already know that these thermal properties will/will not be significant.

    Keep up the good work.

    Posted

  • Portyankina by Portyankina scientist

    we need to look at some sort of fluid bed of gas/particulate beneath the ice rather than a void filled with CO2

    • absolutely! Just physically it's not that different from highly pressurized gas - one could have not considered that gas as ideal, so laws of a fluid flow apply anyway. The addition of dust changes a lot erosive force though, you are right here too.

    Anya

    Posted

  • Portyankina by Portyankina scientist in response to Kitharode's comment.

    Well, do not go that deep 😃 The top surface thermal properties are very important to the depth of seasonal heat wave propagation. They do depend a lot on the amount of ground water ice, so they will change from location to location and we hope to find some correlation between activity levels of fans and those.
    Anya

    Posted

  • Kitharode by Kitharode moderator in response to Portyankina's comment.

    Sorry Anya. I'm not quite clear on your response.

    "Well, do not go that deep" - do you mean down deep through the ice, or I'm thinking too deep?
    "The top surface thermal properties..." - Is this top surface of ice layer, or something else?

    Many thanks to you and Portiankina for your input here. And to everyone else, of course.

    Posted

  • Kitharode by Kitharode moderator

    Been looking again at the image on page 1 of this discussion. Before you rush off, have a look at this image from my 'Linear' collection. http://www.planetfour.org/subjects/standard/50e73fa25e2ed211dc0019f1.jpg

    Hopefully you'll see why I call them 'linear' structures. These types of emissions, in many images, are easily seen as lines of vents standing close together - sometimes it looks as if the emissions are gushing from long cracks or crevices because the emission 'holes' are so close together.

    With this in mind, when you revisit the image on page 1, do you still see the edges of a settling fan from a 'point source', or, with due regard to scale and image quality, do you see rows of plumes along these 'edges'?

    Posted

  • Paul_Johnson by Paul_Johnson

    Surely they all eminate from a common source, a pipe of gas, if you will. This is the BBT in action......it's back on!!!

    Posted

  • Kitharode by Kitharode moderator

    Maybe the BBT needs to become an FPT (Flat Pancake Theory)? http://www.planetfour.org/subjects/standard/50e745d65e2ed212400059d8.jpg

    Posted

  • Paul_Johnson by Paul_Johnson

    Come on, those are obviously coming from a connecting source-they just are! No idea why they are circular like this, that is very very interesting....wow.

    Posted

  • Kitharode by Kitharode moderator

    Wow indeed. Interesting yes. How and why, well, there's the rub..... You're loving this aren't you Paul?

    Is your theory 'In a given area all plumes are connected' or 'All plumes come from a single source / reservoir / layer? Or what ... ?
    What is the best evidence you've got that makes you so excited? (Please don't stop being excited).

    Posted

  • Kitharode by Kitharode moderator

    http://www.planetfour.org/subjects/standard/50e742db5e2ed211dc002b74.jpg

    Just found this. Main point source with fan, or on closer inspection is it a 'line' of points? I'd say the latter. Collecting this sort of image has made me that little bit more wary when I see fans - 'Oh, another fan...' might not be strictly correct.

    Posted

  • Wounded_Knee by Wounded_Knee

    If there is a layer under the ice of sumblimated CO2 in the form of a kind of fluid perhaps if the fanfield was positioned in a depression the whole thing might act like an artesian well, this could be the thing that coordinates there eruptions?

    Posted

  • Kitharode by Kitharode moderator in response to Wounded Knee's comment.

    I think depressions are a vital ingredient. Dents, holes, hollows, channels, bowls, whatever. Plumes, like anyone with bi-polar disorder, just won't work properly without a good depression along the line, in my opnion. (Having been diagnosed as bi-polar myself, I think I'm allowed to say that. If not, I apologise).

    Posted

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

    Hi Anya - just wrote a book on the part 2 of this thread - There's water ice under some of these structures? I'm visualising a layer of dust over a more solid base (of rock). Do you know if the spiders fill with windborne dust in the summer?

    Posted

  • wassock by wassock moderator in response to Wounded Knee's comment.

    Hi 'fluid bed' is a bit of a misnomer in this instance it just means a fluid or gas containing a suspended particulate (sort of). If you're old enough to have done metalwork rather than "resistant materials" yould have likely put a plastic coating on some thing buy dunking hot metal in a through of plastic dust with air blowing through it. So you need to be thinking of something that's not really anything like that.

    Posted

  • Kitharode by Kitharode moderator

    You guys will love this one; http://www.planetfour.org/subjects/standard/50e73cfc5e2ed21240000efd.jpg

    Relates more to the original discussions about twin fans and wind directions. I get a strong impression of wind movement from this image. One could almost feel the swirling winds in this region. Wha'dya think?

    Also relating to earlier discussion on blue fans and blue/black fans; If the blue stuff comes out at the same time as the black stuff, might it be that one sort of stuff has more mass than the other, so settles first? Sorry if you've already covered this.

    Posted

  • wassock by wassock moderator

    I'm counting at least 6 different wind directions here, any advance?

    Posted

  • Paul_Johnson by Paul_Johnson

    7! (lol)

    I guess the wind is extremely inconsistant at times, during local squalls etc......but that only serves to highlight the extraordinary circumstances that must arise to allow for the many multiple similar fans that we see. I think this pic highlights the original point better than any other-multiple fans of exactly the same characteristics must be created in fascinating circumstances-which is what we have been exploring, in our own sweet way!

    It has been a fascinating discussion, I feel that, having only been brought into this entire thing from 'Stargazing Live' last week, I have learned so much. I wasnt even really interested in Mars until then!

    Posted

  • wassock by wassock moderator

    What maybe significant here is that hardly any of these have erupted at the same time, so what we see here is multiple fans erupting independently indicating that there's no common cause for them to erupt. where as with the heart/fan fields there must be something which is making them erupt all at the same time. whereas here there's no such commonality

    Posted

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

    "Temporal Independence and Commonality in Point Source Emissions" by Wassock, P. Johnson (and Kitharode?) 😃

    One more image of interest to add relating to this topic:
    http://www.planetfour.org/subjects/standard/50e73f2a5e2ed21240002195.jpg

    Posted

  • Paul_Johnson by Paul_Johnson

    wassock - yes, the BBT! What your saying is perfectly logical to me-some areas have a common gaseous source, some don't.

    Kitharode, there are so many common features in that pic! Come on scientists, concede that some areas may have a common gas source-an under ice reservoir or void. Or even a buried spider network where gas collects.......?

    Posted

  • wassock by wassock moderator

    Yup that looks like a good un wonder how big an area the whole field covers, and what happens at the edges?

    Posted

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

    Kitharode - can you give the discussion link for the image so's I can put it in me personal box, thx

    Posted

  • Kitharode by Kitharode moderator

    Re the BBT / void / common gas source. We're looking for somewhere for the gas to live until the pressure builds, pre-eruption, yes? Up until now, I've imagined an empty space, a chamber if you will (be it a bubble, tunnel, or pancake) that sits beneath the ice layer and above the underlying surface. I assumed that it was the limits of the void (the walls of the chamber) that confined the gas pre-eruption.

    But I'd like your thoughts on the layering, or perhaps continuum would be better, from the top of the ice layer to a given depth in the lithosphere. Ice layer, gas layer, dust layer, rock layer. There's gas in the gas layer for sure, there's room in the dust layer for a good amount, the rock layer may (at the top) be cracked and pitted to create space. I hope you see what I'm getting at. Perhaps the whole area of the southern pole is one huge layer of 'gas space'.

    Posted

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

    Errrr - you'll have to remind me which image you mean. If you can see the image why can't you just grab it?

    Posted

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

    This one http://www.planetfour.org/subjects/standard/50e73f2a5e2ed21240002195.jpg need/want to link into the discussion page for it

    Posted

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

    wrt voids beneath the ice - when the sun first rises in the spring the surface is covered in a layer of ice which rests on top of the mars surface. It's a condensation feature (I think) or maybe tyheres some snow inthere too, but either way it's sat firmly on top of what evers underneath of it - NO VOIDS. If its sat on bare rock then there's very little space available for gas to collect without pushing up the ice (there's another theory in there some where about why you get crack vents in seemingly smooth terrain areas). If there's a layer of dust underneath then there will be space - before the freeze there will have been some atmosphere in there which will likely have only fully frozen after the surface has been sealed by the first frosts of winter - The solid CO2 in the dust will take up less space than would have the atmospheric gas, so there is already space amongst the dust for gas to start subliming into. Oce the first eruption of the season has happened some of the dust and some of the bottom layer of ice will be gone, so there will be room for a larger volume of gas for the next one. Prediction coming up (that can be tested by observation, eek) If this holds true then we should see that eruptions get bigger as the season progresses. If that works then a time line can be established for the various eruptions, using their relative sizes.

    Posted

  • Kitharode by Kitharode moderator

    Re the image. I'm sorry but I don't have a link to a discussion. I picked up the image by chance somewhere and just 'collected' it.

    Re the voids. In short, yes to all. Sadly, we can't do a test by observation with the available images, or can we?

    Posted

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

    Don't know the answer to that one, we need a succession of images of the same thing over a season.

    Posted

  • Wounded_Knee by Wounded_Knee

    Was reading a paper by some Hugarians( Wiki ) while waiting for an x-ray on me knee, says about forms of life living in the tepid flow, Arthur C Clarke wrote about it and was a supporter. I like the idea that life survived in the extremes of the poles in that narrow window, just like Encedalous.😆

    Posted

  • Kitharode by Kitharode moderator in response to Wounded Knee's comment.

    That's Enselados, yes? One of Saturn's moons? You like the idea of life at the extremes "just like on Enselodus". There's an implication there that life has already been found on that moon. Surely you mean "just like there could well be, maybe, perhaps, life there?

    Posted