Scientists find evidence of complex organic molecules from Enceladus

June 27, 2018, Southwest Research Institute
Saturn's moon Enceladus. Credit: NASA

Using mass spectrometry data from NASA's Cassini spacecraft, scientists found that large, carbon-rich organic molecules are ejected from cracks in the icy surface of Saturn's moon Enceladus. Southwest Research Institute scientists think chemical reactions between the moon's rocky core and warm water from its subsurface ocean are linked to these complex molecules.

"We are, yet again, blown away by Enceladus. Previously we'd only identified the simplest organic molecules containing a few carbon atoms, but even that was very intriguing," said SwRI's Dr. Christopher Glein, a space scientist specializing in extraterrestrial chemical oceanography. He is coauthor of a paper in Nature outlining this discovery. "Now we've found organic molecules with masses above 200 atomic mass units. That's over ten times heavier than methane. With emanating from its , this moon is the only body besides Earth known to simultaneously satisfy all of the basic requirements for life as we know it."

Prior to its deorbit in September of 2017, Cassini sampled the plume of material emerging from the subsurface of Enceladus. The Cosmic Dust Analyzer (CDA) and the SwRI-led Ion and Neutral Mass Spectrometer (INMS) made measurements both within the plume and Saturn's E-ring, which is formed by plume ice grains escaping Enceladus' gravity.

"Even after its end, the Cassini spacecraft continues to teach us about the potential of Enceladus to advance the field of astrobiology in an ocean world," Glein said. "This paper demonstrates the value of teamwork in planetary science. The INMS and CDA teams collaborated to reach a deeper understanding of the organic chemistry of Enceladus' than would be possible with only one data set."

During Cassini's close flyby of Enceladus on Oct. 28, 2015, INMS detected molecular hydrogen as the spacecraft flew through the plume. Previous flybys provided evidence for a global subsurface ocean residing above a rocky core. Molecular hydrogen in the plume is thought to form by the geochemical interaction between water and rocks in hydrothermal environments.

"Hydrogen provides a source of chemical energy supporting microbes that live in the Earth's oceans near hydrothermal vents," said SwRI's Dr. Hunter Waite, INMS principal investigator who also was a coauthor of the new paper. "Once you have identified a potential food source for microbes, the next question to ask is 'what is the nature of the complex organics in the ?' This paper represents the first step in that understanding—complexity in the organic chemistry beyond our expectations!"

"The paper's findings also have great significance for the next generation of exploration," Glein said. "A future spacecraft could fly through the plume of Enceladus, and analyze those complex organic molecules using a high-resolution mass spectrometer to help us determine how they were made. We must be cautious, but it is exciting to ponder that this finding indicates that the biological synthesis of on Enceladus is possible."

Explore further: Scientists discover evidence for a habitable region within Saturn's moon Enceladus

More information: Macromolecular organic compounds from the depths of Enceladus, Nature, www.nature.com/articles/s41586-018-0246-4

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15 comments

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Surveillance_Egg_Unit
2.8 / 5 (9) Jun 27, 2018
Due to its 'warm' water underneath its covering of ice, I suspect that Enceladus may have been originally formed/accreted within an orbit that was much closer to the Sun, which might explain its rocky core...as well as its complex organic molecules. It is possible that Enceladus was somehow kicked out of a closer orbit around the Sun and then captured by Saturn's gravity where it assumed its frozen surface.
poksnee
1 / 5 (3) Jun 28, 2018
From dinosaurs undoubtedly.
TeeSquared
2.6 / 5 (10) Jun 28, 2018
"suspect"
"may have been"
"might explain"
"It is possible"
"was somehow"
"it assumed"

Wow, that is a lot of guesswork.
torbjorn_b_g_larsson
5 / 5 (4) Jun 28, 2018
Cool! The CDA could complement the INMS and show large organics, either one compound that is broken down in the mass spectrometer or a complex of them. In either case they are hydrophilic and - as evidenced by the lack of salt in the grains - form an organic film on top of the ocean. Such films form rapidly if the water is organic rich [ https://aslopubs....8.3.0415 ].

Since the organics initially derive from serpentinization reactions at the core - which also helps keep the ocean open - they ara analogous to the alkaline hydrothermal vents that phylogenies has identified as the emergence geology of life on Earth.
torbjorn_b_g_larsson
4.5 / 5 (4) Jun 28, 2018
@SEU: The warmth has other reasons - mainly tidal, but also the carbonacoeus chondritic asteroid core reaction with water ice, see above - and the moon is believed to be one of Saturn's indigenous ones [ https://en.wikipe...f_Saturn ].

@TS: That precision is exactly the opposite of guesswork, it is the commonly seen language of science. Read some papers for reference.
barakn
4.2 / 5 (5) Jun 28, 2018
TeeSquared was referring to Surveillance_Egg_Nut's comment, not to the article, and has been slapped with a large number of undeserved 1s.
TeeSquared
5 / 5 (3) Jun 28, 2018
@TS: That precision is exactly the opposite of guesswork, it is the commonly seen language of science. Read some papers for reference.


I have read a lot of papers. The scientific method is a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

Using terms like "possibly", "might have been", "suspected", "suddenly appeared", "could be", etc ... is not science. It is conjecture. It is a belief that something happened a certain way.
cantdrive85
1.7 / 5 (6) Jun 28, 2018
The organics are likely created by the same electric discharge processes which are eroding the Tiger Stripes of Enceladus. Is there an ocean? Unlikely. The water is more likely created by the same electrochemistry which creates water at comets.
ZoeBell
Jun 28, 2018
This comment has been removed by a moderator.
ZoeBell
Jun 28, 2018
This comment has been removed by a moderator.
Surveillance_Egg_Unit
2.3 / 5 (3) Jun 29, 2018
"suspect"
"may have been"
"might explain"
"It is possible"
"was somehow"
"it assumed"

Wow, that is a lot of guesswork.

says TeeSquared

And don't forget the infamous "as previously thought."
All very irritating when one expects perfection from academics, etc. Not having been witness to the events which I was referring to, the only recourse is to make a guess, educated or otherwise.
jonesdave
1.7 / 5 (6) Jun 29, 2018
The organics are likely created by the same electric discharge processes which are eroding the Tiger Stripes of Enceladus. Is there an ocean? Unlikely. The water is more likely created by the same electrochemistry which creates water at comets.


Idiot. What 'electrochemistry' is creating water at comets, woo boy? Explain it in detail. Step by step. Better still, link us to a peer reviewed paper outlining the production of 1000 l/s from this mysterious 'electrochemistry'.
antialias_physorg
3 / 5 (6) Jun 29, 2018

says TeeSquared

And don't forget the infamous "as previously thought."
All very irritating when one expects perfection from academics, etc. Not having been witness to the events which I was referring to, the only recourse is to make a guess, educated or otherwise.

Erm..he was referring to your first comment which is laden with these unscientific words...not to the actual paper referenced in the article which is very precise (and does not use any of these words).

But it's good to see that you outright stated the difference between useless brainfarts (your posts) and actual science - even though I'm sure you didn't even comprehend what you stated.
TeeSquared
not rated yet Jun 29, 2018
Surveillance_Egg_Unit stated:
All very irritating when one expects perfection from academics, etc. Not having been witness to the events which I was referring to, the only recourse is to make a guess, educated or otherwise.


It is ok to make guesses but to teach those guesses as fact is deceiving.
Surveillance_Egg_Unit
5 / 5 (2) Jun 30, 2018
@SEU: The warmth has other reasons - mainly tidal, but also the carbonacoeus chondritic asteroid core reaction with water ice, see above - and the moon is believed to be one of Saturn's indigenous ones [ https://en.wikipe...f_Saturn ].


says t b g larssen

Thank you for clarifying that for me.

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