Enceladus' south pole is warm under the frost

March 14, 2017
As it swooped past the south pole of Saturn's moon Enceladus on 14 July 2005, Cassini acquired high-resolution views of this puzzling ice world. From afar, Enceladus exhibits a bizarre mixture of softened craters and complex, fractured terrains. This large mosaic of 21 images has been arranged to provide a full-disc view of the anti-Saturn hemisphere on Enceladus. This mosaic is a false-colour view highlighting the long fractures – tiger stripes – in blue. Credit: NASA/JPL/Space Science Institute

Over the past decade, the international Cassini mission has revealed intense activity at the southern pole of Saturn's icy moon, Enceladus, with warm fractures venting water-rich jets that hint at an underground sea. A new study, based on microwave observations of this region, shows that the moon is warmer than expected just a few metres below its icy surface. This suggests that heat is produced over a broad area in this polar region and transported under the crust, and that Enceladus' reservoir of liquid water might be lurking only a few kilometres beneath.

In 2005, observations by the NASA/ESA/ASI Cassini mission revealed plumes of water vapour and ice spraying into space from the south pole of Enceladus, the sixth-largest moon of Saturn. These jets originate from the so-called 'tiger stripes' – four warm fractures in the moon's icy surface. The salty composition of these jets points to an underground sea of liquid water that might interact with Enceladus' rocky core, similar to the sub-surface ocean that is thought to exist on Jupiter's moon, Europa.

Many of Cassini's flybys of Enceladus have been dedicated to understanding the structure of the interior of this fascinating body and its potentially habitable water reservoir. Now, a study based on data collected during a close flyby in 2011 indicates that the moon's hidden sea might be closer to the surface than previously thought.

"During this flyby, we obtained the first and, unfortunately, only high-resolution observations of Enceladus' south pole at microwave wavelengths," says Alice Le Gall from Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and Université Versailles Saint-Quentin (UVSQ), France. Alice is an associate member of the Cassini RADAR instrument team and the lead scientist of the new study, published today in Nature Astronomy.

"These observations provide a unique insight into what is going on beneath the surface. They show that the first few metres below the surface of the area that we investigated, although at a glacial 50-60 K, are much warmer than we had expected: likely up to 20 K warmer in some places," she adds

"This cannot be explained only as a result of the Sun's illumination and, to a lesser extent, Saturn's heating so there must be an additional source of heat."

The detected heat appears to be lying under a much colder layer of frost, as no similar anomaly was found in infrared observations of the same region – these probe the temperature of the surface but are not sensitive to what is underneath.

The South Pole region on Enceladus, the sixth-largest moon of Saturn, imaged by the Imaging Science Subsystem (ISS) on the international Cassini mission. Credit: NASA/JPL-Caltech/Space Science Institute; Acknowledgement: A. Lucas

The observations used by Alice and her collaborators cover a narrow, arc-shaped swathe of the southern polar region, about 500 km long and 25 km wide, and located just 30 km to 50 km north of the tiger-stripe fractures. Because of operational constraints of the 2011 flyby, it was not possible to obtain microwave observations of the active fractures themselves. This had the benefit of allowing the scientists to observe that the thermally anomalous terrains of Enceladus extend well beyond the tiger stripes.

"The thermal anomaly we see at microwave wavelengths is especially pronounced over three fractures that are not unlike the tiger stripes, except that they don't seem to be the source of jets at the moment," Alice says.

These seemingly dormant fractures lying above the warm, underground sea point to a dynamic character of Enceladus' geology: the moon may have experienced several episodes of activity at different locations during its past history.

Even if the cover only a small patch of the southern polar terrains, it is likely that the entire region is warm underneath and Enceladus' ocean could be a mere 2 km under the icy surface. The finding agrees well with the results of a recent study, led by Ondrej Cadek and published in 2016, which estimated the thickness of the crust on Enceladus. With an average depth of 18–22 km, the ice shell appears to reduce to less than 5 km at the south pole.

Alice and her collaborators think that the underground heating source is linked to the tidal cycle of the moon along its eccentric orbit around Saturn. This induces stress compressions and deformations on the crust, leading to the formation of faults and fractures while at the same time heating up the sub-surface layers. In this scenario, the thinner icy crust in the region is subject to a larger tidal deformation that, in turn, releases more heat and contributes to maintaining the underground water in liquid form.

"This discovery opens new perspectives to investigate the emergence of habitable conditions on the icy moons of the gas giant planets," says Nicolas Altobelli, ESA's Project Scientist for Cassini–Huygens.

"If Enceladus' underground sea is really as close to the surface as this study indicates, then a future mission to this moon carrying an ice-penetrating radar sounding instrument might be able to detect it."

Explore further: Enceladus' jets reach all the way to its sea

More information: A. Le Gall et al. Thermally anomalous features in the subsurface of Enceladus's south polar terrain, Nature Astronomy (2017). DOI: 10.1038/s41550-017-0063

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cantdrive85
1.9 / 5 (9) Mar 14, 2017
"This cannot be explained only as a result of the Sun's illumination and, to a lesser extent, Saturn's heating so there must be an additional source of heat."

One of these days the blinders will be lifted, until then just recall the emperor may be nude for all to see.

https://www.nasa....069.html
HannesAlfven
1.8 / 5 (5) Mar 14, 2017
Exhibit A:

http://www.univer...-plumes/

"The CAPS instrument is designed to detect charged gas (plasma), but its measurements in the plume revealed tiny ice grains whose signatures could only be present if they were electrically charged. These grains, probably only measuring a few nanometres across (billionths of a meter – 50, 000 times thinner than a human hair), fall into a size range between gas atoms and much larger ice grains, both of which were sampled directly during previous Enceladus flybys. The particles have both positive and negative electrical charges, and the mix of the charges varied as the Cassini spacecraft crossed the plume."
HannesAlfven
1.8 / 5 (5) Mar 14, 2017
Exhibit B:

http://www.thunde...jets.htm

"Enceladus orbits in the inner regions of Saturn's magnetosphere where the particle flux is high. But "particle flux" is typically nothing more than an astrophysical euphemism for an electrical current. And electric currents in space follow magnetic field lines. Within Saturn's magnetosphere Enceladus will encounter currents in the polar regions. It seems probable that the south polar region of Enceladus has its own magnetic field, which could concentrate an electrical current in that region. In fact, sharp gradients in the magnetic field were encountered during Cassini's closest approach to Enceladus—a typical indicator of current boundaries."
HannesAlfven
1.7 / 5 (6) Mar 14, 2017
Exhibit C:

http://lasp.color...rint.pdf

The auroral footprint of Enceladus on Saturn

"Here we report the detection of magnetic-field-aligned ion and electron beams (offset several moon radii downstream from Enceladus) with sufficient power to stimulate detectable aurora, and the subsequent discovery of Enceladus-associated aurora in a few per cent of the scans of the moon's footprint. The footprint varies in emission magnitude more than can plausibly be explained by changes in magnetospheric parameters—and as such is probably indicative of variable plume activity."

Which is the cause and which is the effect? They seem to assume the answer, without ever asking the question.
gkam
2.3 / 5 (6) Mar 14, 2017
Enceladus seems to be a better candidate for a lander than Europa. And sampling near the tiger stripes could show us what blew out of them and landed nearby, perhaps without drilling down.
691Boat
4.3 / 5 (6) Mar 14, 2017
"This cannot be explained only as a result of the Sun's illumination and, to a lesser extent, Saturn's heating so there must be an additional source of heat."

One of these days the blinders will be lifted, until then just recall the emperor may be nude for all to see.

https://www.nasa....069.html


FYI, your link calls out magnetic reconnection. I thought that was a fairytale?
cantdrive85
1.5 / 5 (8) Mar 14, 2017
It most certainly is, when you bit down on that electrical cord when you were a kid did the doctor explain you were a victim of magnetic reconnection?
cantdrive85
1.6 / 5 (7) Mar 14, 2017
BTW, the important aspect of the link is the observations, not the interpretation.
Osiris1
not rated yet Mar 14, 2017
So Enceladus, a frosty margarita of an Io on the rocks, and like Io likely has lots of volcanos under the ice. An under ice ocean could have a steep temperature gradient and tremendous pressure. That water would be saturated with volcanic gasses and the ice volcanoes will blow off harder than a diet coke/mentos/loose lid cocktail when it fizzes thru the ice. Any life will be similar to those found in vicinity of the undersea Marianas Trench volcanic vents that can live at high temps and pressures and die if removed. Positing a very deep sea, there would be ample space for a goldie-glubb-glubb zone, but question is what it would live on. Plenty of energy and stable temps so life will find a way to quote Laura Dern from the movie Jurassic Park.
Captain Stumpy
4.2 / 5 (5) Mar 14, 2017
@idiot nazi sympathizing pseudoscience cult members from eu
BTW, the important aspect of the link is the observations, not the interpretation.
you mean like this?
http://www.pppl.gov/node/857

Researchers have run this and similar experiments —called "shots" — more than 100,000 times since 1995 and amassed volumes of data and numerous scientific papers.
http://www.pppl.g...HEET.pdf

holy cow!
more than 100,000 experiments that validate the science!

how many eu experiments refute MR?
oh... right
zero
zilch
none!

you were saying?
yep
1.7 / 5 (3) Mar 15, 2017
They are definitely doing some cool stuff there!

In the spirit of Reality Check this article has some common ground for Cantdrive and the Captain because we are going to all end up in the same place eventually.

http://www.pppl.g...tability
jonesdave
5 / 5 (5) Mar 15, 2017
Exhibit C:

http://lasp.color...rint.pdf

The auroral footprint of Enceladus on Saturn

"Here we report the detection of magnetic-field-aligned ion and electron beams (offset several moon radii downstream from Enceladus) with sufficient power to stimulate detectable aurora, and the subsequent discovery of Enceladus-associated aurora in a few per cent of the scans of the moon's footprint. The footprint varies in emission magnitude more than can plausibly be explained by changes in magnetospheric parameters—and as such is probably indicative of variable plume activity."

Which is the cause and which is the effect? They seem to assume the answer, without ever asking the question.


Stop being an idiot. The cause is quite obviously underground. Tidal heating. As shown by this study. No electric woo. Burke.
jonesdave
5 / 5 (4) Mar 15, 2017
It most certainly is, when you bit down on that electrical cord when you were a kid did the doctor explain you were a victim of magnetic reconnection?


In fact, the most interesting plasma physics occurs precisely where and because this equation is not satisfied, such as the auroral acceleration region, ***magnetic field reconnection***, turbulence, shocks, and many wave modes.


G-G. Falthammar & F. S. Mozer (2007)
http://onlinelibr...0002/pdf
jonesdave
5 / 5 (4) Mar 15, 2017
They are definitely doing some cool stuff there!

In the spirit of Reality Check this article has some common ground for Cantdrive and the Captain because we are going to all end up in the same place eventually.

http://www.pppl.g...tability


Why does it have common ground? What is the idiotic EU claim?

Only a source of internal heat has been considered on Enceladus........The crucial discovery is the "completely unexpected surprise" of the similarity of the chemistry of the jets of comets and Enceladus. It should not have been a surprise. The jets of both are an electric discharge phenomenon, heating the surface.


From the idiot Thornhill. http://www.holosc...c-moons/
And this (amongst other things) shows the idiot to be wrong. As usual. So where is this common ground?
jonesdave
5 / 5 (6) Mar 15, 2017
More classic pseudoscience from the previously linked Thornhill BS:

The cometary nature of Enceladus doesn't merely "raise many questions on the formation of the Saturn system." It raises serious questions about the modern mythology of the formation of the entire solar system. If we are to take the concept of consilience seriously, and I think it is an imperative if we are to have a cosmology that answers all questions, then we must understand the ancient references to electrical activity in the heavens that is beyond modern experience. ***We must grasp the meaning of the thunderbolts of the gods***.


Lol.
jonesdave
5 / 5 (6) Mar 15, 2017
Yet more from the idiot Thornhill:

This finding favors the electric discharge sputtering mechanism. It is precisely that mechanism that operates on comet nuclei to produce jets and that produced expressions of surprise when the fineness and limited size distribution of comet dust was first measured.


http://www.holosc...-plumes/

This would be the "precise mechanism" that Rosetta failed to observe, despite over 2 years in close proximity to a comet, with the types of instruments that would have detected such woo. Yet another horrendous pile of fail from the woomeister-in-chief.
jonesdave
5 / 5 (4) Mar 15, 2017
So, to summarise the above; the idiot Thornhill thinks that some sort of electric woo is causing the H2O emissions from Enceladus. He rails against real scientists for only considering internal heat sources, when he thinks (in his befuddled, unqualified mind) that the heating should only be on the surface due to the aforementioned impossible electric woo.
A study, as outlined in the article, shows the idiot Thornhill to be wrong (surprise, surprise), and that the heating is coming from below the jets.
Despite this, we have two of his cheerleaders prancing round in their fetching mini skirts, claiming that this is somehow a vindication for the electric woo hypothesis. You couldn't make it up. Well, Thornhill did, but that is no reason for any educated adult to believe the cretin. Hey ho.
cantdrive85
1 / 5 (5) Mar 15, 2017
There goes jonesdumb again, laying down ad hominem attacks and labeling all he doesn't understand as "woo".
A study, as outlined in the article, shows the idiot Thornhill to be wrong (surprise, surprise), and that the heating is coming from below the jets.

Where else would you expect the heat to originate with electric discharge, er sorry, woo?
691Boat
5 / 5 (5) Mar 15, 2017
Where else would you expect the heat to originate with electric discharge, er sorry, woo?


You have any calculations regarding the amount of energy going into Enceladus via plasma to cause these geysers? If the geysers are caused by electric discharge as you claim, how long do typical electric discharges last? Just curious since what I have read says that these geysers are constant. I would imagine an electric discharge event would cause a spike in the geysers, but they have only seen changes in the geysers due to gravity from Saturn.
Captain Stumpy
4.3 / 5 (6) Mar 15, 2017
In the spirit of Reality Check this article has some common ground for Cantdrive and the Captain because we are going to all end up in the same place eventually.

http://www.pppl.g...tability
@yep
3 stars from me
i have to challenge your argument that we will end up in the same place simply because of the following:
1- i follow the evidence - it doesn't matter what the end result is if it's validated by science simply because i don't have a vested interest in protecting any worldview or belief system

2- cd is an advocate for a worldview and wants to force their beliefs onto everyone else - and it really is a belief because if it were valid and validated science there wouldn't be any argument from anyone but the church/pope (and even they're more accepting of proven science than the eu cult)

nowhere does cd argue a point with actual valid/validated evidence - just quotes
gkam
1 / 5 (6) Mar 15, 2017
Electricity did not do it.

And they are not geysers.

Just look at the pictures: The stuff is falling out of the South Pole.

As good as some other theories.
Captain Stumpy
4.3 / 5 (6) Mar 15, 2017
To piggyback on 691Boat's post
If the geysers are caused by electric discharge as you claim, how long do typical electric discharges last? Just curious since what I have read says that these geysers are constant
adding to that... why isn't it reported and proven given our evidence collected if plasma is the driving force as the eu claims?

that isn't speculation either as Tokar et al 2006 was looking specifically at that interaction, The Interaction of the Atmosphere of Enceladus with Saturn's Plasma

before you eu nutters claim conspiracy again, or make sh*t up about astro's not knowing plasma physics:
-you should read the contributing authors and their affiliations in the studies
-you should note that this is based upon collected measured evidence
Captain Stumpy
4.3 / 5 (6) Mar 15, 2017
To piggyback on 691Boat's post cont'd
so we know what plasma is capable of doing, then we should be able to see the charge that causes such an incredible display of force on Enceladus... but:
The Cassini Radio and Plasma Wave Science instrument inferred little plasma density increase near Enceladus. These data are consistent with ion formation via charge exchange and pickup by Saturn's magnetic field. The charge exchange occurs between neutrals in the Enceladus atmosphere and corotating ions in Saturn's inner magnetosphere. Pickup ions are observed near Enceladus, and a total mass loading rate of about 100 kilograms per second (3 × 1027 H2O molecules per second) is inferred
http://science.sc...766/1409

so as anyone can see, regardless, there is no way it's plasma considering the evidence
much like dirt devils, moon craters, the grand canyon and D/1993 F2
cantdrive85
1 / 5 (6) Mar 15, 2017
I would imagine an electric discharge event would cause a spike in the geysers, but they have only seen changes in the geysers due to gravity from Saturn

There is your problem, your "imagination" regarding electric discharge is utterly meaningless. And the changes have only been inferred to be the result of gravity.
691Boat
5 / 5 (7) Mar 15, 2017
I would imagine an electric discharge event would cause a spike in the geysers, but they have only seen changes in the geysers due to gravity from Saturn

There is your problem, your "imagination" regarding electric discharge is utterly meaningless. And the changes have only been inferred to be the result of gravity.

OK then genius, since my imagination doesn't apply, tell me how long these electric discharges last, how frequent they are, how much energy is transferred per event/unit time, what is the source of the energy? No imagination required, just pure science. Facts. Math. Proof. Go.
Captain Stumpy
5 / 5 (5) Mar 15, 2017
There is your problem, your "imagination" regarding electric discharge is utterly meaningless
@nazi sympathizing eu pseudoscience cult idiot
except it isn't imagination
i mean... it's not like we didn't have any measurements that were taken at the same time as the pics, you idiot
http://science.sc...766/1409

so read the data collected from the measurements and, as 691Boat asks
tell me how long these electric discharges last, how frequent they are, how much energy is transferred per event/unit time, what is the source of the energy? No imagination required, just pure science. Facts. Math. Proof. Go.
that should be easy enough considering the wealth of data from Cassini etc...
jonesdave
5 / 5 (6) Mar 16, 2017
that should be easy enough considering the wealth of data from Cassini etc...


Don't be silly, Captain. Quantitative data? From EU cultists? They can't even describe the mechanism, beyond some vague claim of "it's electric woo". Ask them how the electric comet rubbish went. Again, they never had a hypothesis in the first place. And what does the idiot Thornhill do when his rubbish is shown to be the rubbish we all knew it would be? Ignore it, and hope that nobody remembers his unqualified rantings. Welcome to the world of electric woo.
As for the idiot cantthink; where should we expect the heating to come from? The surface, according to the dipsh*t Thornhill: http://www.holosc...c-moons/
Wrong, wasn't he? What temperature should we expect to see from this electric woo? What temperature is the water? What signatures should we see from this electric woo? When the spacecraft has flown through the plumes? Any answers? Nope, didn't think so.

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