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Jet Spots in Tiger Stripes
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Alliance Member Comments
Tiger (Apr 19, 2008 at 4:29 PM):
I believe you are in middle or high school cmckay? Your have an awesome sense of chemistry and physics!
NeKto (Apr 17, 2008 at 6:11 PM):
Respected cmckay! you made an important point; that the non biological source for the hydrocarbons does not preclude biological activity. our wonderful little robot friend has given us a great deal of information to work with. with great teams like ciclops, jpl and others working on the data, i anticipate fascinating answers and more intriguing questions!
And Tiger, the most fundamental question the Saturn system poses to us is one i do not believe Cassinni can answer; that is the fundamental nature of gravity itself. i am confident that anyone on this forum agrees gravity exists. we know a lot about how it works, but what we know so far still cannot explain the complexities we see in the Saturn system. if i am not mistaken, human exploration of the Saturn system has generated more controversy in gravitational theory than anything else since the inseption of gravitational theory. Tiger (Apr 13, 2008 at 4:43 PM):
Hi professor,I was just wondering if you there are mysreries about Saturn that cannot be solved...even with Cassini
cmckay (Apr 13, 2008 at 1:05 PM):
Tsesarevich
Yes, ethlyene (C2H2) is another C2 compound I should have listed. There is only one C1 but there are 3 C2 compounds. C typically has four bonds. In methane these all go to H. When there are 2 Cs then these two Cs can join with a single bond leaving three bonds for H for each carbon (ethane C2H6), double bond leaving 2 bonds for H for each carbon (ethlyene C2H4) or triple bond leaving only one bond for a H (acetylene- official name is ethyne, C2H2). Working this same logic there are many possible combinations of C3, even more C4 etc. As I said, biogenic sources of CH4 tend not to also produce C2 and C3 compounds. A quick look at the spectrum from the INMS on the March 2008 flyby seems to show comparable levels of C2, C3 etc compared to C1. This would seem to suggest a non biological source of the methane. Even if true, this not rule out biology in the system, just says that the methane is not produced by methanogens. NeKto (Apr 12, 2008 at 12:37 PM):
thank you cmckay. i was wondering what indicators could tell us about the source of the organic molecules. what you say about the mass spectrum makes sence to me. (i had forgotten how rare C2 hydrocarbons are in biomass!) it does lean toward non biological. So biological processes appear to be very unlikely as the energy source. that is the big riddle, where is the heat coming from? (by the way, you didn't mention C2H4)
Tiger (Apr 5, 2008 at 4:31 PM):
Thanks chris! You`re a genius!
cmckay (Apr 5, 2008 at 10:01 AM):
Tiger (Tyler) and others. A brief reminder about organic molecules might help explain what the INMS can do. The INMS detects the mass of individual molecules. Methane is the simplest organic molecule it has 1 carbon connected to 4 hydrogen atoms. Total mass is 16 mass units. The next more complex hydrocarbon is ethane with 2 carbons each connected to 3 hydrogens. Total mass is 30. Acetylene is a different hydrocarbon that also has 2 carbons but each one is connected only to one hydrogen. Total mass 26. As the number of carbon atoms an organic molecule has the number of possible different combinations becomes quite large. Looking at the number of molecules with one carbon atom sometimes called C1 (only methane, CH4) and comparing that to the number of atmosphere with two carbon atoms called C2 (ethane C2H6, acetylene C2H2) and comparing these to the C3 atoms (C3H6, C3H2 etc.) and C4, and C5. We see a series going from simple to complex. The INMS can measure up to total mass 100 so that would include benzene (C6H6 mass = 6X12+6=76) but not much more.
The relative concentration of C1 to C2,C3,C4 etc. may indicate a biological source. A biological source makes much more C1 than other. While non biological source tend to make them all. Quick look at the spectrum from the March flybe seems most consistent with a non-biological source. carolyn (CICLOPS) (Apr 4, 2008 at 3:18 PM):
Yes, it can distinguish between molecules of different mass. How well it does at measuring the abundance of any molecule depends on how much of the molecule is present. See Chris McKay's comment about this in a diff't earlier thread.
Tiger (Apr 4, 2008 at 1:35 PM):
Then how come it can`t distinguish the real amount of carbons? You said earlier that there may be 3...or even 4 carbons.
carolyn (CICLOPS) (Apr 4, 2008 at 12:59 PM):
Tiger: This is not the way it works. The INMS instrument measures the mass of the molecules it collects. It can distinguish between molecules that contain one or two carbons by determining that one is heavier than the other. There is no `processing' of two carbons to make a single molecule. Nature does that!
Tiger (Apr 4, 2008 at 9:14 AM):
professor,this comment may not make any sense because I don`t really understand the situation about the methane and acetylene. Well, remember when you said that there may be more than 2 carbons of methane? According to my opinion,the way to know is to let the IMNS machine process the 2 carbons. If they make an atom,then there is only 2 carbons. But if they don`t make an atom,then there must be more existing carbons. So piece the carbons together until the results make sense. It`s like a puzzle.
carolyn (CICLOPS) (Mar 27, 2008 at 6:34 PM):
Harry....of course we are modeling such things. We want to figure out if it's possible, with all the evidence in hand, to determine the likelihood that we have liquid water beneath the surface somewhere. The resolution of the IR is much poorer than the resolution of the imaging data. So we don't know how wide really the hottest temps, along the tiger stripe fractures, are. If we assume the region that is hot is very narrow, you get hotter temps than if you assume it is wider. And heat conduction would make the warm temps spread out horizontally. But the heat coming from below would also be carried by the diffusion of vapor (which carries heat) upward.
Interesting, huh? Harry (Mar 27, 2008 at 5:34 PM):
I expect that there will be a lot of post processing done on these overlapped infrared and visual images. Can you provide any rough idea of the differences in the spacial resolution of the infrared image with respect to the visual image? I presume that the region of higher surface temperature is wider than the visual "tiger strip" feature. Other than heat transfer of the vented material coming from the "tiger strip", the rest of the heat signature must come from thermal conduction of the surface "ice". I hope someone is modeling this heat transfer equation to formulate ideas of how deep "tiger strip" fissures are and possibly the ambient temperature of the subsurface heat source.
Again, great work! I am sure that interpretations of these features will take years to produce. Patience is a virtue that is a struggle to master. Harry from Houston. MartinL (Mar 26, 2008 at 1:36 PM):
Hello, dear carolyne and all your kollegues, you are the greatest!
Your findings are so very interesting, that i look forward to all your newsletters. You all do a lot more than a good job, your work is fascinating and not possible without a great enthusiasm. I lift my hat in front of you!! May be the force with you all the time! best wishes from Stuttgart/ Germany to you all!!! Martin
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