Talk:Enceladus/Archive 2

Archive 1

Archive 2

Lead section - tagged

I tagged the lead section for a rewrite because:

• Water plumes have 3 separate entries just within the introduction.
• Water is mentioned about 14 times.
• Lead section should ideally contain no more than four paragraphs and be carefully sourced as appropriate.

Thank you, BatteryIncluded (talk) 16:43, 4 April 2014 (UTC)

Agreed (except sources are optional in material is referenced in the body of the article) and will add that it does a poor job of summarizing anything in the article except for the possible presence of water. --ThaddeusB (talk) 19:37, 4 April 2014 (UTC)

Rewrite

Hi,

How 'bout this for the intro paragraphs? I tried to get rid of stuff thats old scientific opinion and integrate todays new announcements better. Please add your input and what else should be changed. Thanks Reedman72 20:57, 4 April 2014 (UTC)

Enceladus is the sixth-largest moon of Saturn. It was discovered in 1789 by William Herschel.Until the two Voyager spacecraft passed near it in the early 1980s very little was known about this small moon besides the identification of water ice on its surface. The Voyagers showed that the diameter of Enceladus is only 500 kilometers (310 mi), about a tenth of that of Saturn's largest moon, Titan, and that it reflects almost all of the sunlight that strikes it. Voyager 1 found that Enceladus orbited in the densest part of Saturn's diffuse E ring, indicating a possible association between the two, while Voyager 2 revealed that despite the moon's small size, it had a wide range of terrains ranging from old, heavily cratered surfaces to young, tectonically deformed terrain, with some regions with surface ages as young as 100 million years old.

In 2005 the Cassini spacecraft performed several close flybys of Enceladus, revealing the moon's surface and environment in greater detail. In particular, the probe discovered a water-rich plume venting from the moon's south polar region. This discovery, along with the presence of escaping internal heat and very few (if any) impact craters in the south polar region, shows that Enceladus is geologically active today. Moons in the extensive satellite systems of gas giants often become trapped in orbital resonances that lead to forced libration or orbital eccentricity; proximity to Saturn can then lead to tidal heating of Enceladus's interior, offering a possible explanation for the activity.

On April 3 2014, NASA reported that evidence for a large underground ocean of liquid water on Enceladus had been found by the Cassini spacecraft. Cryovolcanoes at the south pole shoot large jets of water vapor, other volatiles, and some solid particles like [[NaCl] crystals and ice particles into space, totaling approximately 200 kg per second. Some of this water falls back onto the moon as "snow", some of it adds to Saturn's rings, and some of it reaches Saturn. The discovery of the plume has added further weight to the argument that material released from Enceladus is the source of the E ring.

Because of the presence water at or near the surface, Enceladus may be one of the best places to look for extraterrestrial life. By contrast, the water thought to be on Jupiter's moon Europa is locked under a very thick layer of surface ice, though recent evidence may show that Europa also experiences water plumes.Analysis of the outgassing suggests that it originates from a body of subsurface liquid water, which along with the unique chemistry found in the plume, has fueled speculations that Enceladus may be important in the study of astrobiology. According to the scientists at Nasa, evidence of an underground ocean suggests that Enceladus is one of the most likely places in the Solar System to "host microbial life".

--— Preceding unsigned comment added by Reedman72 (talk • contribs)

References

Looks good. I say go for it - it is certainly better than what we have now. I would drop the last sentence as it is largely redundant in some should be a brief summary (it can and should be included in the body). There are a few other tweaks I might make, but for copyright reasons it would be cleaner if you paste your text into the article and then I edit it rather than making the tweaks here. --ThaddeusB (talk) 22:52, 4 April 2014 (UTC)

Ok, thanks man. It has been a featured article for a long time ('06 I think) and it has kinda lost some of its "featuredness" and I hope to help it out. Reedman72 23:08, 4 April 2014 (UTC) — Preceding unsigned comment added by Reedman72 (talk • contribs)

Glad to hear it. I was actually going to nominate it to be improved or delisted as it is definitely not up to current FA standards. The lead was the worst problem - I will have a list of a few other later. --ThaddeusB (talk) 23:59, 4 April 2014 (UTC)

Yes a list would help very much. I'd rather improve it than have to delist it but I think the sectioning is kinda messy. Reedman72 00:07, 5 April 2014 (UTC) — Preceding unsigned comment added by Reedman72 (talk • contribs)

Holy smokes! You guys are busy! The intro looks very good now. And also thanks to user 79.67.241.229 for his relentless energy fixing the references throughout Wikipedia. Thank you all. Cheers, BatteryIncluded (talk) 13:42, 5 April 2014 (UTC)

I do not believe the "explanation" regarding tidal forces supposedly melting the ice in the core of Enceladus. Based on the Second Law of Thermodynamics, I believe we can demonstrated why the temperature gradient is far steeper (and applied over an extra 55Km) leading to the temperature being naturally above 273K. (In just 9Km in Earth's outer crust it gets up to about 540K in a German borehole.) See my note at the end of this Talk page. — Preceding unsigned comment added by 101.191.120.218 (talk) 08:28, 17 January 2016 (UTC)

Major reorganization needed

I can't do this myself as I am not intimately familiar with the article; however, right now the "Characteristics" section is largely written in chronological order, and needs to be regrouped into topical order. You can't have two sections on a subsurface ocean, for instance. Serendi^podous 05:54, 5 April 2014 (UTC)

I have not read the whole article yet but I did notice, and agree, that the subsurface ocean entries should be coalesced to eliminate repetition. Same with its habitability potential. Cheers, BatteryIncluded (talk) 21:07, 5 April 2014 (UTC)

The first thing i'm doing is taking orbit out of characteristics, im just gonna go ahead with this one. Im taking a cue from Europa it has it that way. Thanks Reedman72 02:15, 6 April 2014 (UTC) — Preceding unsigned comment added by Reedman72 (talk • contribs)

"Tidal heating" section

This is one of many article adjustments coming: Other article sections dismiss tidal heating AND a subsurface ocean at equilibrium, but this section ends with "tidal heating on Enceladus may account entirely for a subsurface ocean at equilibrium". If tidal heating is an old displaced hypothesis, it must be deleted, or presented with a reduced importance weight, or mentioned briefly only for historical context. Need to read the research in a chronological context, determine the present model of 1) hydrostatic (dis)equilibrium; 2) the most likely heat source, and adjust this section/article accordingly. Cheers, BatteryIncluded (talk) 17:47, 6 April 2014 (UTC)

Pre-FA review comments

This article is currently not up to current feature article standards. If not improved, I intended to send it to WP:FAR for review. Here is a list of some things which need fixed:

• There are a number of old comments on this talk page that say such-and-such is confusing or inaccurate that were never answered. These need reviewed and addressed where appropriate.
• BatteryIncluded has just tagged several sentences/sections that need attention.
• As noted above, the article is repetitive and/or poorly organized in the "physical characteristics" subsections.
• Eyeballing it, about 20% of the article is unreferenced. All but the most obvious facts should be cited in a FA.
• The list of Cassini flybys is out of date.
• The date formatting (in particular in references) in inconsistent. The original authors appear to have used "January 1, 1900" type dates, so all dates should be converted to that format (no 1900-01-01 or 1 January 1900 dates).

• Don't agree - dates should be 1900-01-01 format, since at least 95% of them already are - at this stage, it doesn't matter what the original authors did, that is ancient history. hamiltonstone (talk) 02:10, 30 April 2014 (UTC)

• Reference formatting is inconsistent, including some refs with bare URLs. The easiest way to fix is to convert all refs to cite news/cite journal/cite book/etc. templates.
• The number of external links is excessive and should be trimmed.

That is all for now, ThaddeusB (talk) 18:46, 6 April 2014 (UTC)

My biggest problems with it are how the subsurface ocean, now being official, is referred to as possible. Also i have reed that its discovery has something to do with its high albedo making it possible to see something a few hundred km wide millions of miles a way in the 18th century. Reedman72 (talk) 21:40, 6 April 2014 (UTC)

I agree with Reedman; That is one typical example of the kind of overhaul it needs. My impression so far of this article is that new discoveries were entered as they happened, but the article was not updated as a whole. There is a chronological structure to it rather than currently known facts, and almost every entry claims to be the latest. From the scientific perspective, it needs a thorough review to update the whole article, not just enter new data. I seems to me some important sentences need to be referenced and -unfortunately- most entries may need to be verified against the cited reference AND, further, find out if they are still current hypotheses. Not a quick fix for a single editor, as this requires of commitment to read the references and use them in the correct context. Cheers, BatteryIncluded (talk) 22:48, 6 April 2014 (UTC)

So, the article saw significant improvements during the first half of April, but there are definitely still some problems. It is now well organized, but there still seems to be significant chunks of unreferenced text. I realize that it isn't a quick fix to verify the info is still current and reference it, but there haven't been any edits in 10 days or so. As such, I am wondering if there is still interest in improving the article? --ThaddeusB (talk) 04:34, 26 April 2014 (UTC)

@ ThaddeusB, can you please mark the statements or sections you think need more references? I will make the time to look them up. Thank you. --BatteryIncluded (talk) 15:51, 26 April 2014 (UTC)

I have added cn tags to some places that I think need references. Some statements may be OR or editorializing, and some may just need the previous reference use extended. I will also complain about some references. The Herschel, W. (1790) reference almost certainly will have online readable text and so should be linked. Many other web references should state the date and publisher. A question: should journal names be linked? Or does this just cause confusion for where to click to read the reference? Graeme Bartlett (talk) 08:56, 27 April 2014 (UTC)

I added the best [missing] references I was able to find and read. I still have to go over the whole text and verify the older references support the inline citation. Also, I will let someone else cleanup all the references' format. Cheers, - BatteryIncluded (talk) 02:24, 28 April 2014 (UTC)

Is anyone working on the section tagged for update Enceladus#Atmosphere? DrKay (talk) 19:30, 20 November 2015 (UTC)

Is it 5th or 6th largest.

According to our article on the moons of saturn its both sixth most massive and most voluminous. The order is Titan, Rhea, Iapetus, Dione, Tethys, Enceladus. An IP changed it from sixth to fith (sic). If its an error lets fix it quick.

Reedman72 (talk) 22:14, 6 April 2014 (UTC)

Heat source

I spent most of 12 hours reading papers on the likely heat sources. Measurements and interpretations varied with time and techniques, which caused confusion not just in this article, but in the planetary science circles. Basically, tidal heating could not produce more than 1.1 gigawatts power, but the observed infrared signals are much greater than that. One estimate went as high as 15.9 GW, and the latest (2013) brought it down to 4.7 GW. Scientists are still not able to justify the "excess" heat observed emanating from the south pole (tiger stripes). I may have done mistakes in the review, but the punchline is that the heat source must be actually combination of sources; tidal heating is one, but the rest remain a mystery. CHeers, BatteryIncluded (talk) 05:05, 7 April 2014 (UTC)

Does the maximum figure of 1.1 GW include the effect of excitation by the other Saturnian moons? --JorisvS (talk) 09:30, 8 April 2014 (UTC)

It should. The model seems well accepted, so it should include all nearby planetary bodies capable of contributing to the tidal heat. BatteryIncluded (talk) 12:17, 8 April 2014 (UTC)

All right. What about a local decrease of thermal insulation? --JorisvS (talk) 13:12, 8 April 2014 (UTC)

It seems the hot spots in the south pole are not because a thinner crust or decreased insulation, but because of the fissures (tiger stripes). BatteryIncluded (talk) 13:28, 8 April 2014 (UTC)

Well, if there is warm material flowing out of the fissures, that would effectively decrease the thermal insulation in those areas. --JorisvS (talk) 14:28, 8 April 2014 (UTC)

The image for the cryovolcanism shows the surface ice temperature as "-77K". It is probably 77K and someone just tossed in the negative sign. I dont know the real temp so i figured i would just mention it and leave it to someone who knows to fix it. — Preceding unsigned comment added by 50.79.188.77 (talk) 14:42, 9 April 2014 (UTC)

Good question. Actually, the image displays not -77K but a tilde, squiggly line (~) which means "approximately" 77K. Thank you. BatteryIncluded (talk) 18:01, 15 April 2014 (UTC)

Ice

It may be obvious but it needs to be made clearer that Enceladus is an icy moon. It isn't mentioned in the intro and it isn't mentioned in the surface features section. Ice and water are a fairly important part of its identity. Serendi^podous 08:51, 28 April 2014 (UTC)

Reliability of source

Does anyone have a view on why this webpage prepared by someone called Alexander Clarke should be considered a reliable source? (currently used in footnote 45). hamiltonstone (talk) 02:12, 30 April 2014 (UTC)

The cleanup is a work in progress. Thank you. --BatteryIncluded (talk) 07:34, 30 April 2014 (UTC)

Flattening of Enceladus's rotation axis...

Regarding:

... have led to a flattening of Enceladus's rotation axis ...

How can a rotation axis be flattened? Isn't it the moon itself that is being flattened? --Mortense (talk) 21:18, 8 June 2014 (UTC)

Yes it sounds weird. I'll read the references and context. --BatteryIncluded (talk) 01:57, 9 June 2014 (UTC)

The source (Porco et alii) actually says "more oblate" and "less oblate". I've restored the sentence and fixed the wording. Tbayboy (talk) 03:32, 9 June 2014 (UTC)

Stop it!

People, quit moving this page back and forth without getting a consensus. Double sharp: saying "we should discuss this" in an edit summary while moving a page over a move over a move... what gives?? hamiltonstone (talk) 03:14, 20 June 2014 (UTC)

I've moved it back for the discussion. (I still think that it looks odd if it's the only moon not needing dismabiguation, and that some other moons in the Solar System may well also be way more well known than their mythological counterparts. (I also note that we have situations Chaldene redirecting to Chaldene (moon), with no article on the mythological character: granted that's not exactly a major moon, but shouldn't we also have the article without disambiguation?) Double sharp (talk) 03:28, 20 June 2014 (UTC)

Similar arguments have been brought up elsewhere on Wikipedia, for example here and here. Consistency is important, but as those discussions show, consistently following WP:PRECISE outweighs consistency with using the same parenthetical disambiguations, especially when those parenthetical disambiguations are unnecessary. Precision shouldn't be ignored just because other articles are at their appropriate levels of precision. If other articles have unnecessary parenthetical disambiguations, the solution would be to fix those articles and bring them in line with Wikipedia guidelines rather than to add unnecessary parenthetical disambiguations to article titles just to have them "match". (Also, thank you for moving it back and discussing it) - Aoidh (talk) 03:40, 20 June 2014 (UTC)

OK, I see. I think I'll go through some of the other moons and remove the disambiguation where it's not necessary. I'm sorry about the repeated moves. Double sharp (talk) 10:03, 20 June 2014 (UTC)

Question about intro paragraph

The third paragraph of the intro reads, in part:

...Enceladus is geologically active today. Moons in the extensive satellite systems of gas giants often become trapped in orbital resonances that lead to forced libration or orbital eccentricity. Enceladus is in such a resonance with Saturn's fourth largest moon, Dione. Enceladus's proximity to Saturn leads to tidal heating of its interior, offering a possible explanation for the activity.

I'm wondering whether there is any logical relation between sentences 2&3 and sentence 4. Geological activity comes from tidal heating which comes from proximity, but does proximity have anything to do with Dione resonance? Thanks, AxelBoldt (talk) 17:18, 15 March 2015 (UTC)

Tidal forces lead to dissipation of heat, but at some point an equilibrium state is reached. Perturbations from other satellites bring it out of this equilibrium, and those of satellites with which it is in resonance tend to be the strongest (which is the "that lead to forced libration or orbital eccentricity" part). The order of the sentences is not ideal and how they say it is not something a layman would understand. Especially the last sentence is off. I have taken a shot at improving it. --JorisvS (talk) 20:53, 15 March 2015 (UTC)

@JorisvS: Thanks a lot; being a layman, I can confirm that it makes a lot more sense now. I think the sentence about the ocean fits better in the second paragraph though; I'll give it a shot. AxelBoldt (talk) 15:31, 16 March 2015 (UTC)

That's good! And I think your move makes sense, too. --JorisvS (talk) 18:25, 16 March 2015 (UTC)

Saturn Moon's Ocean May Harbor Hydrothermal Activity

I just got this in the Mensa Weekly Brainwave:

11 Mar 2015 (Source: NASA Jet Propulsion Laboratory)

Things to know:

• Cassini finds first evidence of active hot-water chemistry beyond planet Earth
• Findings in two separate papers support the notion
• The results have important implications for the habitability of icy worlds

NASA's Cassini spacecraft has provided scientists the first clear evidence that Saturn's moon Enceladus exhibits signs of present-day hydrothermal activity which may resemble that seen in the deep oceans on Earth. The implications of such activity on a world other than our planet open up unprecedented scientific possibilities.

"These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms," said John Grunsfeld, astronaut and associate administrator of NASA's Science Mission Directorate in Washington. "The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the universe."

Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth's oceans. According to two science papers, the results are the first clear indications an icy moon may have similar ongoing active processes.

The first paper, published this week in the journal Nature, relates to microscopic grains of rock detected by Cassini in the Saturn system. An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon's rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).

"It's very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on -- and beneath -- the ocean floor of an icy moon," said the paper's lead author Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder.

Cassini's cosmic dust analyzer (CDA) instrument repeatedly detected miniscule rock particles rich in silicon, even before Cassini entered Saturn's orbit in 2004. By process of elimination, the CDA team concluded these particles must be grains of silica, which is found in sand and the mineral quartz on Earth. The consistent size of the grains observed by Cassini, the largest of which were 6 to 9 nanometers, was the clue that told the researchers a specific process likely was responsible.

On Earth, the most common way to form silica grains of this size is hydrothermal activity under a specific range of conditions; namely, when slightly alkaline and salty water that is super-saturated with silica undergoes a big drop in temperature.

"We methodically searched for alternate explanations for the nanosilica grains, but every new result pointed to a single, most likely origin," said co-author Frank Postberg, a Cassini CDA team scientist at Heidelberg University in Germany.

Hsu and Postberg worked closely with colleagues at the University of Tokyo who performed the detailed laboratory experiments that validated the hydrothermal activity hypothesis. The Japanese team, led by Yasuhito Sekine, verified the conditions under which silica grains form at the same size Cassini detected. The researchers think these conditions may exist on the seafloor of Enceladus, where hot water from the interior meets the relatively cold water at the ocean bottom.

The extremely small size of the silica particles also suggests they travel upward relatively quickly from their hydrothermal origin to the near-surface sources of the moon's geysers. From seafloor to outer space, a distance of about 30 miles (50 kilometers), the grains spend a few months to a few years in transit, otherwise they would grow much larger.

The authors point out that Cassini's gravity measurements suggest Enceladus' rocky core is quite porous, which would allow water from the ocean to percolate into the interior. This would provide a huge surface area where rock and water could interact.

The second paper, recently published in Geophysical Research Letters, suggests hydrothermal activity as one of two likely sources of methane in the plume of gas and ice particles that erupts from the south polar region of Enceladus. The finding is the result of extensive modeling by French and American scientists to address why methane, as previously sampled by Cassini, is curiously abundant in the plume.

The team found that, at the high pressures expected in the moon's ocean, icy materials called clathrates could form that imprison methane molecules within a crystal structure of water ice. Their models indicate that this process is so efficient at depleting the ocean of methane that the researchers still needed an explanation for its abundance in the plume.

In one scenario, hydrothermal processes super-saturate the ocean with methane. This could occur if methane is produced faster than it is converted into clathrates. A second possibility is that methane clathrates from the ocean are dragged along into the erupting plumes and release their methane as they rise, like bubbles forming in a popped bottle of champagne.

The authors agree both scenarios are likely occurring to some degree, but they note that the presence of nanosilica grains, as documented by the other paper, favors the hydrothermal scenario.

"We didn't expect that our study of clathrates in the Enceladus ocean would lead us to the idea that methane is actively being produced by hydrothermal processes," said lead author Alexis Bouquet, a graduate student at the University of Texas at San Antonio. Bouquet worked with co-author Hunter Waite, who leads the Cassini Ion and Neutral Mass Spectrometer (INMS) team at Southwest Research Institute in San Antonio.

Cassini first revealed active geological processes on Enceladus in 2005 with evidence of an icy spray issuing from the moon's south polar region and higher-than-expected temperatures in the icy surface there. With its powerful suite of complementary science instruments, the mission soon revealed a towering plume of water ice and vapor, salts and organic materials that issues from relatively warm fractures on the wrinkled surface. Gravity science results published in 2014 strongly suggested the presence of a 6-mile- (10-kilometer-) deep ocean beneath an ice shell about 19 to 25 miles (30 to 40 kilometers) thick.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency's Science Mission Directorate in Washington. The Cassini CDA instrument was provided by the German Aerospace Center. The instrument team, led by Ralf Srama, is based at the University of Stuttgart in Germany. JPL is a division of the California Institute of Technology in Pasadena.

More information about Cassini, visit:

http://www.nasa.gov/cassini

and

http://saturn.jpl.nasa.gov

Preston Dyches Jet Propulsion Laboratory, Pasadena, Calif. 818-354-7013 preston.dyches@jpl.nasa.gov

Dwayne Brown NASA Headquarters, Washington 202-358-1726 dwayne.c.brown@nasa.gov

Source web site, gorgeously illustrated with uncopyrighted drawings:

http://solarsystem.nasa.gov/news/display.cfm?News_ID=48922

☺ Dick Kimball (talk) 16:36, 17 March 2015 (UTC)

MansourJE (talk) 11:06, 7 May 2015 (UTC)

Curtain Erruptions

New research and photos from Cassini satellite shows diffusing volcanic activities rather than discrete jets. Read more on the following like: http://phys.org/news/2015-05-saturn-moon-curtain-eruptions.html MansourJE (talk) 15:40 7 May 2015 (UTC)

FWIW - the following image => File:PIA19061-SaturnMoonEnceladus-CurtainNotDiscrete-Eruptions-20150506.jpg - seems related - and has been added to the main Enceladus article - also available => more images & video animation - iac - Enjoy! :) Drbogdan (talk) 11:41, 7 May 2015 (UTC)

Although Hubble and Cassini have seen the plumes, it may be useful to note that some scientists think it may be a very rare phenomenon to exploit or rely on.[1] -Cheers, BatteryIncluded (talk) 17:15, 7 May 2015 (UTC)

That's only about Europa, not Enceladus. --JorisvS (talk) 17:55, 7 May 2015 (UTC)

Sorry! BatteryIncluded (talk) 17:56, 7 May 2015 (UTC)

Merge discussion at Talk:Life on Enceladus

There is an ongoing discussion at Talk:Life on Enceladus about whether to merge Life on Enceladus into Enceladus. Any reasoned comments would be helpful. A2soup (talk) 15:16, 16 August 2015 (UTC)

Global ocean

I fail to see why evidence for a global ocean is not worthy of the lede but a previous line about evidence for a localised South-polar sea is? Can someone enlighten me? ChiZeroOne (talk) 23:54, 15 September 2015 (UTC)

That not really either, just a general sentence about the existence of a subsurface ocean. The details can be given in the section about it. That's one of the things that have to be cleaned up. People tend to put new findings in the lead, even though often they don't belong there. More often than not that stuff stays there. --JorisvS (talk) 00:07, 16 September 2015 (UTC)

Global ocean and disequilibrium

Is it possible to have a global ocean with a crust on top that does not have the shape corresponding to hydrostatic equilibrium? If it does, how could it support the disequilibrium? --JorisvS (talk) 23:49, 3 October 2015 (UTC)

Why is this article so good?

I mean, Enceladus is just a small moon, sixth largest Saturnian moon, it doesn't have a huge potential for life, etc. Congratulations to those who brought it to featured article status. Huritisho 05:16, 6 October 2015 (UTC)

Yes, a global subsurface water ocean with energy sources is over-rated. BatteryIncluded (talk) 06:47, 6 October 2015 (UTC)

NASA-TV/ustream (10/26/2015@2:00pm/et/usa) - "Enceladus FlyBy" Teleconference.

NASA-TV/ustream and/or NASA-Audio (Monday, October 26, 2015@2:00pm/et/usa) - NASA will detail an "Historic FlyBy" through a "plume of icy spray" of Enceladus on 11:22 am/et/usa Wednesday, October 28, 2015 - Enjoy! :) Drbogdan (talk) 02:10, 23 October 2015 (UTC)

BRIEF Followup - REPLAY LINK (Audio; 43:41) => http://www.ustream.tv/recorded/76308203 - Enjoy! :) Drbogdan (talk) 19:37, 28 October 2015 (UTC)

References

WP:BOLD removal of Atmosphere section

I have removed the atmosphere section of this article after concluding that scientific discussion of Enceladus's atmosphere to date has focused almost exclusively on the south polar plumes, which are adequately covered by the Cryovolcanism section. More explanation of this below. Feel free to revert and discuss here if you disagree with my rationale.

Reviewing all four references for the Atmosphere section, two were press articles from March 2005, when NASA apparently announced the discovery of an atmosphere on Enceladus. The other two ([2] [3]) were from scientific papers published together a year later in March 2006. Tellingly, in their abstracts, neither paper discusses an atmosphere, but both discuss plumes from Enceladus's south polar region (one paper uses the term "atmospheric plume"). With information from the Cryovolcanism section (referenced to one of the same papers from the Atmosphere section), I pieced together the story behind this: in January and February 2005, Cassini unexpectedly detected water over Enceladus, which NASA reported to the press as the discovery of an atmosphere (hence the March 2005 articles). Further observations in mid and late 2005 "determined that gases in Enceladus's atmosphere are concentrated over the south polar region, with atmospheric density away from the pole being much lower", i.e. the "atmosphere" initially detected turned out to be plumes from the south polar region. This explains why the scientific papers from March 2006 discuss plumes rather than atmosphere. A cursory search for other scientific papers on Enceladus's atmosphere revealed that almost all of them discuss the south polar plumes exclusively. While Enceladus has a very thin global atmosphere (probably from the plumes), I don't think that the scientific literature to date allows us to write a section on it that is meaningfully different from the Cryovolcanism section. A2soup (talk) 12:28, 12 January 2016 (UTC)

A more likely reason for the Enceladus paradox

We need to understand that there is a gravitationally induced temperature gradient* that forms at the molecular level and is based on the quotient of the acceleration due to gravity and the weighted mean specific heat of the solids, liquids or gases involved. We see this in all planets and satellite moons. We can indeed explain the small temperature increase of about 30 degrees between the surface and core in Mimas using the specific heat of ice. But Enceladus (diameter 500Km) has just over twice the volume of Mimas (diameter 390Km) and greater density due to the rock. This means that the force of gravity may well be three or four times as great. Also, because of the lower specific heat of most rocks, that also makes the temperature gradient steeper. It is not out of the question that the temperature of the core might get above 273K (not the estimated 180K to 200K) because of these factors and the fact that there is a greater distance between surface and core, thus not even requiring the supposed heating by tidal forces.

• The gravitationally induced temperature gradient results directly from the maximum entropy production as per the Second Law of Thermodynamics. Maximum entropy is attained when all unbalanced energy potentials have dissipated. Since changes in molecular gravitational potential energy obviously affect entropy, there must be a homogeneous sum of gravitational potential energy (PE) and kinetic energy (KE). Since PE varies with height, so too does KE vary equally. We equate PE gain and KE loss to compute the temperature gradient from Kinetic Theory. This information has been available since the 19th century.

— Preceding unsigned comment added by 101.191.120.218 (talk) 08:13, 17 January 2016 (UTC)

An important policy here at Wikipedia is no original research. Essentially, everything on Wikipedia must be verifiable using published sources. Because of this, even if you are correct about why Enceladus has liquid water, your theory cannot be included in the article unless you can provide a reliable source that proposes it. This policy can seem silly at first, but the focus on verifiability is one of the main features that has made Wikipedia a quality source for information. WP:Verifiability, not truth is a good essay on this subject. A2soup (talk) 08:25, 17 January 2016 (UTC)

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 Done, archive URL is ok. --Zefr (talk) 16:12, 24 December 2016 (UTC)

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 Done, both links ok. --Zefr (talk) 16:38, 24 December 2016 (UTC)

Albedo

Bond albedo 0.99, which now is given in the article, is given in many places in Internet, but I don't see it in any high-quality sources. There exist values 0.81 ± 0.04 for (bolometric) Bond albedo (Cassini data, source) and 0.91 ± 0.10 for visual spherical and, supposedly, Bond albedo (Voyager data, source; but geometric albedo in this source strongly discords with modern value). If no other sources would be found, value of Bond albedo should be replaced with 0.81 ± 0.04. Stas (talk) 03:43, 3 February 2017 (UTC)

Since no ideas appeared, I replaced the data. Stas (talk) 23:44, 7 February 2017 (UTC)

Discovery, which telescope?

This article asserts that the discovery was made with Wilhelm Herschel’s 40-foot telescope.

Other sources report that he had seen it earlier with one of his 20-ft telescopes. Check Google Books: https://books.google.com/books?id=9b00AAAAQBAJ&pg=PR51&dq=enceladus+discovery+herschel&hl=en&sa=X&ved=0ahUKEwjOqozPkJDTAhUXS2MKHT1wDyMQ6AEIPDAE#v=onepage&q=enceladus%20discovery&f=false

I'm surprised that there is no mention of this important detail of the discovery in a Featured Article.

--Gaff (talk) 15:22, 6 April 2017 (UTC)

There are numerous reports that the 40 ft telescope was "too cumbersome", encouraging frequent use of the 20 ft which is attributed to discovering Enceladus in 1789, including here and here. --Zefr (talk) 22:25, 6 April 2017 (UTC)

Missing: Saturn Electric Link!

An artist's concept shows a glowing patch of ultraviolet light near Saturn's north pole that occurs at the "footprint" of the magnetic connection between Saturn and its moon Enceladus. In this image, the footprint is in the white box marked on Saturn, with the magnetic field lines in white and purple. A larger white square above Enceladus shows a cross-section of the magnetic field line between the moon and the planet. This pattern of energetic protons was detected by Cassini's magnetospheric imaging instrument (MIMI) on Aug. 11, 2008.

Sadly this article has detailed hypotheses about Enceladus but fails to include an important observed fact, anyway here are the sources (from 2011!):

• Cassini Sees Saturn Electric Link With Enceladus, article on NASA website.
• Cassini Sees Saturn Electric Link with Enceladus, article on JPL website.
• Electrical Circuit Between Saturn and Enceladus, image page on JPL website.
• Beams of electrons link Saturn with its moon Enceladus, article on Phys.org.

The image is already on wikimedia. I've done the hard work, who is doing the write up? --DelftUser (talk) 09:43, 24 April 2017 (UTC)

Habitability?

This term, habitability, seems to be used a lot in science reporting. I think it provides a connotation of "you and I can live there", but in fact, what we are really trying to indicate is the possibility of life on Enceladus.

I'd like to replace "Potential habitability" with "Potential for life on Enceladus" or "Potential for life".

What do you think?

Kortoso (talk) 19:46, 19 September 2017 (UTC)

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Pronunciation

I know its typical to refer to naive English form for pronouncing ancient South European language names, but its often in error, for example in this case, en-sell-a-dus (instead of the normal en-sel-ah-dus) the accent on the second syllable only works when pronouncing with unnecessary speed, and with a strange pronunciation of the third syllable /uh/ instead of simply /ah/. The unnecessary speed comes as typical with reading unusual form spellings, but is clumsy. Linked through science news article. -Inowen (talk) 03:43, 28 February 2018 (UTC)

On the contrary, the word has been Anglicised with the stress on the second syllable. A Greek pronunciation might be appropriate in some circumstances, but the second-syllable stress with reduced third and fourth syllables is now standard English (where the rhythm is different from that of southern European languages). Dbfirs 08:24, 28 February 2018 (UTC)

Source of the E ring

A circular reference to an article that cites Wikipedia?

Section: Source of the E ring, second paragraph, first sentence:

"Mathematical models show that the E ring is unstable, with a lifespan between 10,000 and 1,000,000 years; therefore, particles composing it must be constantly replenished.[40]"

Reference [40] is "Cassini visits Enceladus - New light on a bright world" By Salvatore Vittorio, CSA Discovery Guides, July 2006 , and has this sentence from the bottom of page 3 to the top of page 4:

Numerous mathematical models have shown Saturn’s E ring to be unstable, with a lifespan between 10,000 and 1,000,000 years, and so the particles composing it need to be constantly replenished. ... [1]

Reference [1] in the Vittorio paper is this Wikipedia article.

I'm no planetary scientist, but papers such as Juhasz and Horanyi (2002) suggest lifetimes more like 10 years. I'll keep looking for a more recent reference. Perhaps a real planetary scientist can provide a better number and a real reference, rather than this self-reference.

KeithLofstrom (talk) 04:40, 15 November 2019 (UTC)

References

Some proposed change [COI]

• Text to change: On June 27, 2018, scientists reported the detection of complex macromolecular organics on Enceladus's jet plumes, as sampled by the Cassini orbiter. These indicate potential hydrothermal activity on the moon driving complex chemistry . On June 7, 2021, astronomers reported detecting substantial amounts of methane, a possible sign of microbial life, on Enceladus.

• Suggested change: The Cassini orbiter performed chemical analysis of Enceladus's plumes, finding evidence for hydrothermal activity , possibly driving complex chemistry. Ongoing research on Cassini data suggests that Enceladus's hydrothermal environment could be habitable to some of Earth's hydrothermal vents microorganisms, and that plume-found methane could be produced by such organisms .
• Reason for change: Affholder et al. 2021 did not find large amounts in the plume (they used quantities reported in Waite et al. 2017 for their analysis) but found that this reported amount is too large to be explained by serpentinization chemistry alone. They also find that a modeled population of Earth's hydrothermal vents microbes could explain the observed methane levels. Because this research is very recent and thus subject to scientific debate, I think caution is advised (and thus the suggested "Ongoing research...").
• Reference supporting change: see references in suggested change
• Disclaimer: I am Antonin Affholder, leading author of the 07 June study in Nature Astronomy and thus possibly subject to conflict of interest.

References

--AAffholder (talk) 12:18, 12 July 2021 (UTC)

 Done @AAffholder: and others - updated the relevant text in the main article - *entirely* ok with me to rv/rm/mv/ce the edit of course - iac - Stay Safe and Healthy !! - Drbogdan (talk) 14:37, 12 July 2021 (UTC)

Conflict with article on the Forty-Foot Telescope

I've noticed that there is a factual conflict between this article and the 40-foot telescope article which should be resolved. This article states: "Enceladus was discovered by William Herschel on August 28, 1789, during the first use of his new 1.2 m (47 in) 40-foot telescope, ..." The 40-foot telescope article is not as definitive: "It may have been used to discover Enceladus and Mimas, the 6th and 7th moons of Saturn." Since this is a featured article and I know nothing about the topic, I don't want to make any changes, but I think two closely related articles should be factually consistent. Enjoyed reading both! Mr Serjeant Buzfuz (talk) 01:48, 28 August 2021 (UTC)

Suggested clarification

One other point that I noticed is that this article states: "The name, like the names of each of the first seven satellites of Saturn to be discovered, was suggested by William Herschel's son John Herschel in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope" Does that mean that Enceladus did not have a name for the first 50+ years after it was discovered, and wasn't named until 27 years after William Herschel's death? Or did John Herschel suggest the names earlier, and then recounted the origins in his 1847 book? I wasn't clear which was meant? Could this be clarified? Again, I don't know anything about the topic, so don't want to make any changes myself. Mr Serjeant Buzfuz (talk) 01:54, 28 August 2021 (UTC)

Requested move 16 June 2022

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: not moved. There are two fronts under consideration in this RM: the long-term significance dominance of the giant, and the usage front. On long-term significance, there is no consensus on whether the giant has primary long-term significance. On the other hand, the usage front has backfired on the supporters, with the data cited to oppose the moon being primary seemingly in fact supporting the moon's primary status. Overall, the move discussion is not trending in favour of moving. (closed by non-admin page mover) — Ceso femmuin mbolgaig mbung, mellohi! (投稿) 02:08, 30 June 2022 (UTC)

---

• Enceladus → Enceladus (moon)
• Enceladus (disambiguation) → Enceladus

– No clear primary topic for this name, the mythological giant gets about 1/5 the views of the moon daily probably a lower ratio when hits to the moon that continue on to the giant are factored in. This ratio is low as-is, but the giant also has longterm significance vastly exceeding the moon since the moon was named after the giant. These add up to make it so that no primary topic exists. ᴢxᴄᴠʙɴᴍ (ᴛ) 14:30, 16 June 2022 (UTC) — Relisting. >>> Extorc.talk 07:57, 23 June 2022 (UTC)

• Support per nom.--Ortizesp (talk) 18:41, 16 June 2022 (UTC)
• Support per nom. Paul August ☎ 15:38, 17 June 2022 (UTC)
• Support per nom, and with the added bonus of consistency with all other major Saturnian moons. — RAVENPVFF · talk · 09:18, 20 June 2022 (UTC)
• Oppose. The 5-to-1 page view ratio is large. It is dissimilar to cases like Triton (where, in contrast, the moon and mythological figure have roughly equal page views: [4]). Furthermore, there is no reason to believe that "the giant also has longterm significance vastly exceeding the moon", considering that Being the original source of the name is also not determinative of a primary topic (Wikipedia:Disambiguation#Primary topic). Indeed, if one wanted to debate about long-term significance, I would argue that it also favors Enceladus the moon. The moon is of great scholarly interest (and pop-sci interest too), as is immediately apparent on Google Scholar, while the giant is a mythological figure of minor interest (scholarly or popular). Astronomers frequently write papers (and book chapters, and even whole books) devoted to Enceladus the moon, while classicists scarcely devote such works to the giant. I think that says a lot about the relative "enduring notability and educational value" of the two topics. Adumbrativus (talk) 05:36, 22 June 2022 (UTC)

  If people didn't think the giant was important, why (in space) would they ever name an entire moon after it? Your argument contradicts itself. ᴢxᴄᴠʙɴᴍ (ᴛ) 22:59, 26 June 2022 (UTC)

• Leaning support I agree being the original isn't determinate but it should at least be a more than minimal factor. Crouch, Swale (talk) 12:07, 22 June 2022 (UTC)
• Oppose - View ratio very much supports this being the primary topic, as does a general search online to see what is meant when people search for the word Enceladus; it is overwhelmingly the moon they are referring to. Even if each view on the giant's page were a followthrough from this page, and we were to take away those views from this page, that still means that this page is over 4 times as viewed as the other topic. That shows an overwhelming interest in this article over the other, making this the clear primary topic with respect to usage. The giant having longterm significance does not create primacy by any means, as it was a very minor mythological figure even within its field, and the moon itself also has longterm significance and is much more significant in its field than the giant is in its own field. Merely being older does not matter. Per WP:DPT: "While long-term significance is a factor, historical age is not determinative." As to Ravenpuff's comment on consistency with the other moons, Wikipedia policy, specifically WP:CONSIST, makes it clear that parenthetical disambiguation is not something that needs to be consistent between similar subjects. - Aoidh (talk) 13:12, 22 June 2022 (UTC)
• Relisters comment : There are arguments presented by opposes of the move and supporters agree with Nom, currently there is no consensus for either actions so I'm relisting for thorough consensus. >>> Extorc.talk 07:57, 23 June 2022 (UTC)
• Oppose per User:Adumbrativus. The moon article is primarytopic by both usage and significance. "Being named after" is a very minor consideration (see Boston versus Boston, Lincolnshire). The status quo is better for readers and editors alike. Dohn joe (talk) 16:27, 23 June 2022 (UTC)

  The longterm significance criterion says otherwise. It is not a "minor consideration" in all cases. ᴢxᴄᴠʙɴᴍ (ᴛ) 22:57, 26 June 2022 (UTC)

• Per WP:DPT, it is a very minor consideration, to the point that it means almost nothing in terms of determining primacy. "Being the original source of the name is also not determinative." An argument that rests on the idea that the moon being named after the giant creates primacy for the giant is directly and unambiguously contradicted by Wikipedia guidelines on the matter. - Aoidh (talk) 23:06, 26 June 2022 (UTC)

@Aoidh: Being "not determinative" only means that it is not enough, by itself, to determine primacy. It does not mean that it is a very minor consideration, to the point that it means almost nothing as you assert. Something being older than something else is a significant consideration in determining primacy. But an even more important consideration is "long term significance" which is much more than just one thing being older than another. In the example of Boston, Massachusetts and Boston, Lincolnshire, while the latter name is roughly 170 years older, the former has been more famous for over 200 years. Compare that with the Giant which is at least 2,500 years older than the moon, and probably only less famous since the last 30 years at most. Paul August ☎ 14:01, 27 June 2022 (UTC)

"Something being older than something else is a significant consideration in determining primacy" is directly contradicted by WP:DPT: "historical age is not determinative." As for long-term significance, the giant does not have "substantially greater enduring notability and educational value". There is zero evidence presented for that claim in this move discussion other than the age and the fact that the moon is named after the giant, both of which are, by Wikipedia consensus, not determinative aspects of long-term significance. - Aoidh (talk) 16:43, 27 June 2022 (UTC)

To use an example listed on Wikipedia:Disambiguation as to why historical age and being named after something else does not create primacy, Anne Hathaway is the page for the actress, who is the primary topic, even though there is another Anne Hathaway (Shakespeare's wife) who is significantly older and was very well known. Also, the actress was even named after Shakespeare's wife, the same exact arguments being made here for the giant. Yet still, the primary topic is the actress for the reasons I listed above. Despite being recent, within our lifetimes, the actress is by far who is being referred to when someone says "Anne Hathaway". Similarly, and this is supported by checking online (I did a general Google search, Google Scholar, and JSTOR), if someone says the word Enceladus, they are overwhelmingly referring to the moon, to the point that outside of the one Wikipedia result for the giant, I didn't see a single reference to the giant within the first few pages of any engine I checked. In general English usage, the word Enceladus is by default about the moon. That is primacy. - Aoidh (talk) 17:07, 27 June 2022 (UTC)

• Oppose - The Saturnian moon, is the primary topic. GoodDay (talk) 16:52, 27 June 2022 (UTC)
• Oppose. It's hard to overlook a 5:1 disparity in page views. The moon being named after the mythical figure is irrelevant per WP:DPT, which clearly states "Being the original source of the name is also not determinative." -- Vaulter 17:11, 27 June 2022 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Surface gravity

There's an error in the reported surface gravity under physical characteristics. 0.113 m/s2 does not equal 0.0113 g. One of those values must be wrong. 50.216.38.129 (talk) 13:44, 16 February 2023 (UTC)

 Fixed –LaundryPizza03 (dc̄) 03:38, 18 February 2023 (UTC)

Huge "plume"

The media (or at least my Bing homepage) is reporting that a huge plume is coming out of Enceladus. I doubt this is reliable information (source: it reports that these are "signs of alien life", despite Wikipedia telling them that these are normal for Enceladus) but maybe this is worthy of inclusion? 104.187.66.104 (talk) 22:39, 30 May 2023 (UTC)

Coverage seems to be specific to the James Webb Space Telescope's new findings about something that is already known, e.g. [5]. It should be covered at Enceladus#South polar plumes if it is suitable for inclusion. –LaundryPizza03 (dc̄) 23:08, 30 May 2023 (UTC)