CICLOPS: Cassini Imaging Central Laboratory for OPerationS

Enceladus Plume Neutral Mass Spectrum
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Enceladus Plume Neutral Mass Spectrum
PIA 10356

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  The lower panel is a mass spectrum that shows the chemical constituents sampled in Enceladus' plume by Cassini's Ion and Neutral Mass Spectrometer during its fly-through of the plume on Mar. 12, 2008. Shown are the amounts, in atomic mass per elementary charge (Daltons [Da]), of water vapor, methane, carbon monoxide, carbon dioxide, simple organics and complex organics identified in the plume.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Ion and Neutral Mass Spectrometer was designed and built at Southwest Research Institute (SwRI), and the team is at SwRI in San Antonio, Texas.

Released: March 26, 2008 (PIA 10356)
Image/Caption Information

Alliance Member Comments
jsc248 (Apr 3, 2008 at 4:52 AM):
These new results are tanalising indeed but I think that I'm more looking forward to the flyby in four and a half months time. The spectral analysis of organic origin is fascinating but to image the sourse of the plumes, now that (for me!) is the one to see!
toomanytribbles (Apr 1, 2008 at 7:58 PM):
freeze-dried micro-organisms in the E ring: yummy.
cmckay (Mar 31, 2008 at 11:33 AM):
The easist way to see what the INMS can really do is to look at the results from Titan. There Cassini flow down to the 1000 km level and the INMS obtained a rich organic spectrum. The results are in Waite et al 2007 in Science. Specific organics were detected up to C6H6. If we could get comparable counts for the organics from the plume of Enceladus we should be able to get a hint as to how the abundance falls off with carbon number. A sharp falloff from C1 (methane) to C2 (ethane and acetylene) would be consistent with a biological source for the methane.
carolyn (CICLOPS) (Mar 31, 2008 at 9:11 AM):
So far all we know is that there are compounds that are heavier than methane. These are likely compounds with two carbons -- like acetylene -- and maybe even three and four carbons. It's not clear to me that the INMS instrument can distinguish, however, ethane (C2H6) from other C2 compounds. Hopefully, someone who really knows the answer to this -- Chris M? -- will chime in here.
LOONYMAN (Mar 31, 2008 at 4:35 AM):
Welcome Chris, and thanks for taking the time to join us here and share your wisdom with us!!!
Has cassini given us any results as to the ethane content of the plume yet?
I am sure I speak for everyone here when I say that Enceladus has us all sitting on the edge of our seats regarding the chances for exobiology, and it is very much appreciated that you guys keep us "fans" around the world updated as to current progress and thinking.

carolyn (CICLOPS) (Mar 30, 2008 at 5:29 PM):
Alliance members: Our newest member, in the event that you didn't recognize him, is none other than Chris McKay, distinguished planetary scientist and pre-eminent astrobiologist. He knows of what he speaks, and we're lucky to have him commenting on these pages. Thanks, Chris. Anytime you're moved to visit and comment, please do so!
cmckay (Mar 30, 2008 at 5:23 PM):
Hello, new to this site at the invitation of Carolyn Porco. Looking at the interesting discussion and one area that I can comment on is the methane. While it is true that methane can form as a breakdown product of organics at high temperature it can also be formed biologically. It is interesting that the microbial ecosystem on Earth that is my favorite candidate for an ecosystem on either Europa or Enceladus is based on methanogens. The usual way to tell biogenic from abiogenic methane is with isotopes - not an option on Cassini. However the ratio of ethane to methane is another way. Biogenic production of methane tends to be pretty pure methane while thermogenic production of methane make 1% or more ethane as well.
sverba (Mar 27, 2008 at 7:21 AM):
So what is the next step in analysis - will you be able to dig any deeper into the complex organics? Actually it might be worth first clarifying what 'complex organics' actually means technically and whether these compound are also possible signatures for life or just biochemistry gone wild.
Red_dragon (Mar 27, 2008 at 4:40 AM):
A fine job!. If just we had the CDA data...
LOONYMAN (Mar 27, 2008 at 3:15 AM):
Fantastic results !!! Very exciting and well done on even more great science.
I have a question, do the results show any chemical disequilibrium that could be attributed to organic activity, I know that methane is quickly broken down in some environments, could this be an indicator of something more interesting going on inside?
Prot_on (Mar 26, 2008 at 4:37 PM):
Carolyn.. I usually refer to it as "The Mrs. Paul's Effect".

carolyn (CICLOPS) (Mar 26, 2008 at 2:59 PM):
Ed.. Very imaginative, but ... uh ... not likely. However, I've said myself we might have freeze-dried micro-organisms in the E ring!
Prot_on (Mar 26, 2008 at 2:21 PM):
This brings to mind a quote attributed to Freeman Dyson about Europa:

Every time a major impact occurs on Europa, a vast quantity of water is splashed from the ocean into the space around Jupiter. Some of the water evaporates, and some condenses into snow. Creatures living in the water far enough from the impact have a chance of being splashed intact into space and quickly freeze-dried.
Therefore, an easy way to look for evidence of life in Europa's ocean is to look for freeze-dried fish in the ring of space debris orbiting Jupiter. Sending a spacecraft to visit and survey Jupiter's ring would be far less expensive than sending a submarine to visit and survey Europa's ocean. Even if we did not find freeze-dried fish in Jupiter's ring, we might find other surprises -- freeze-dried seaweed, or a freeze-dried sea monster."


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