APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

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APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby APOD Robot » Sun Apr 16, 2017 4:12 am

Image Life-Enabling Plumes above Enceladus

Explanation: Does Enceladus have underground oceans that could support life? The discovery of jets spewing water vapor and ice was detected by the Saturn-orbiting Cassini spacecraft in 2005. The origin of the water feeding the jets, however, was originally unknown. Since discovery, evidence has been accumulating that Enceladus has a deep underground sea, warmed by tidal flexing. Pictured here, the textured surface of Enceladus is visible in the foreground, while rows of plumes rise from ice fractures in the distance. These jets are made more visible by the Sun angle and the encroaching shadow of night. A recent fly-through has found evidence that a plume -- and so surely the underlying sea -- is rich in molecular hydrogen, a viable food source for microbes that could potentially be living there.

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby bystander » Sun Apr 16, 2017 4:13 am

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

RocketRon

Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby RocketRon » Sun Apr 16, 2017 4:46 am

So has anyone/anything tried this hydrogen diet yet ?
It might be just me, but it sounds a bit thin.

But you never know what might be out there....

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby neufer » Sun Apr 16, 2017 5:13 am

RocketRon wrote:
So has anyone/anything tried this hydrogen diet yet ?
It might be just me, but it sounds a bit thin.

But you never know what might be out there....
https://en.wikipedia.org/wiki/Methanogenesis wrote:
<<Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. Organisms capable of producing methane have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria. The production of methane is an important and widespread form of microbial metabolism. In most environments, it is the final step in the decomposition of biomass. Some humans produce flatus that contains methane. In one study of the feces of nine adults, only five of the samples contained archaea capable of producing methane.

Methanogenesis in microbes is a form of anaerobic respiration. Methanogens do not use oxygen to respire; in fact, oxygen inhibits the growth of methanogens. The terminal electron acceptor in methanogenesis is not oxygen, but carbon. The carbon can occur in a small number of organic compounds, all with low molecular weights. The two best described pathways involve the use of acetic acid and inorganic carbon dioxide as terminal electron acceptors:

    CO2 + 4 H2 → CH4 + 2H2O

    CH3COOH → CH4 + CO2
However, depending on pH and temperature, methanogenesis has been shown to use carbon from other small organic compounds, such as formic acid (formate), methanol, methylamines, tetramethylammonium, dimethyl sulfide, and methanethiol.

The presence of atmospheric methane has a role in the scientific search for extra-terrestrial life. The justification is that methane in the atmosphere will eventually dissipate, unless something is replenishing it. If methane is detected (by using a spectrometer for example) this may indicate that life is, or recently was, present. This was debated when methane was discovered in the Martian atmosphere by M.J. Mumma of NASA's Goddard Flight Center, and verified by the Mars Express Orbiter (2004) and in Titan's atmosphere by the Huygens probe (2005). This debate was furthered with the discovery of 'transient', 'spikes of methane' on Mars by the Curiosity Rover.

It is also argued that atmospheric methane can come from volcanoes or other fissures in the planet's crust and that without an isotopic signature, the origin or source may be difficult to identify.

On 13th April 2017, NASA confirmed that the dive of the Cassini orbiter spacecraft on 28 October 2005 discovered the Enceladus plume which has all the ingredients for methanogensis based life forms to feed from. Previous results, published in March 2015, suggested hot water is interacting with rock beneath the sea; the new findings support that conclusion and add that the rock appears to be reacting chemically. From these observations scientists have determined that nearly 98% of the gas in the plume is water, about 1% is hydrogen and the rest is a mixture of other molecules including carbon dioxide, methane and ammonia.>>
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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby De58te » Sun Apr 16, 2017 10:55 am

RocketRon wrote:So has anyone/anything tried this hydrogen diet yet ?
It might be just me, but it sounds a bit thin.
I think that is a typo. I read on another site, space dot com, I think, that the gases hydrogen AND carbon dioxide were detected in the plumes. Those two gases can form methane which is the viable food.

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby Coil_Smoke » Sun Apr 16, 2017 2:25 pm

Evidence of non-terrestrial life...? What are the 3 "Cigar Shaped" objects seen in this image ? The upper 2 could be dropouts in data. The lowest seems inclined and crossing more then one scan line.

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby Chris Peterson » Sun Apr 16, 2017 2:37 pm

Coil_Smoke wrote:Evidence of non-terrestrial life...? What are the 3 "Cigar Shaped" objects seen in this image ? The upper 2 could be dropouts in data. The lowest seems inclined and crossing more then one scan line.

Probably cosmic ray strikes. Two of the streaks could possibly be background sources (stars?) if the exposure was moderately long and the camera was tracking the moon.
Chris

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby heehaw » Sun Apr 16, 2017 9:33 pm

I am so old that I remember a story from the beginning of the space program when we did not even know if radio communication with astronauts we might send to Mars would even be possible. Which led to a joke: our astronaut, from whom we had not heard a word in years, finally did return from Mars. When he had landed, there was of course a press conference. He was asked, "is there life on Mars?"
He replied: "Yep ... long about a Saturday night."

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby DavidLeodis » Mon Apr 17, 2017 11:58 am

The "viable food" link made me :) https://kandaceredd.files.wordpress.com/2013/12/baby.jpg.

Finger licking good :ssmile:.

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby ta152h0 » Mon Apr 17, 2017 2:08 pm

when Cassini does a faceplant on Saturn, are the camera's turned on facing the travel direction or facing where it has been ?
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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby neufer » Mon Apr 17, 2017 2:31 pm

ta152h0 wrote:
when Cassini does a faceplant on Saturn, are the camera's turned on facing the travel direction or facing where it has been ?

The camera's turned off, the antenna is facing the Earth and the mass spectrometer is facing the travel direction.

https://saturn.jpl.nasa.gov/mission/gra ... /overview/ wrote:
<<Cassini’s final images will have been sent to Earth several hours before its final plunge, but even as the spacecraft makes its fateful dive into the planet's atmosphere, it will be sending home new data in real time. Key measurements will come from its mass spectrometer, which will sample Saturn's atmosphere, telling us about its composition until contact is lost.>>
Art Neuendorffer

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Re: APOD: Life-Enabling Plumes above Enceladus (2017 Apr 16)

Postby ta152h0 » Mon Apr 17, 2017 4:04 pm

Would it not be a " bummer " if Saturn has a few more surprises ?
Wolf Kotenberg


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