Liquid water near Europa's surface a rarity

Sep 25, 2012
Water near Europa’s surface migrates downwards toward an ocean. Credit: K. Kalousová.

(Phys.org)—Europa, the enigmatic moon of Jupiter, is believed to be home to a subsurface ocean of liquid water. However, future missions to explore Europa's ocean may need to dig deep. Research suggests that water does not stay in a liquid state near Europa's surface for longer than a few tens of thousands of years—the blink of an eye in geological terms. Klára Kalousová will present this work at the European Planetary Science Congress in Madrid on Tuesday 25 September 2012.

Europa is mainly made from rock and iron, with a water shell around 100 km deep beneath a crust of solid ice. The ocean is warmed sufficiently to maintain its by heat produced as a by-product of gravitational pulling to-and-fro from Jupiter.

Pockets of liquid water could be tantalizingly close to the surface. However, Kalousová, from the University of Nantes and Charles University in Prague, believes these would be short-lived. She explains, "A global water ocean may be present, but relatively deep below the surface—around 25 to 50 km. There could be areas of liquid water at much shallower depths, say around 5 km, but these would only exist for a few tens of thousands of years before migrating downwards."

This artist’s cutaway view shows our current understanding of Europa’s interior. Credit: NASA/JPL.

Kalousová reached these conclusions by mathematically modeling mixtures of liquid water and solid ice under different conditions. She found that due to factors such as density and viscosity differences, migrates rapidly downwards through partially molten ice and eventually reaches the .

Other locations in our solar system may be analyzed using this work. Kalousová explains, "As well as helping us to better understand Europa's water cycle, this research could provide insight into icy moons that are geologically active, such as , and worlds that have cycles connecting the interior with a surface atmosphere, such as Titan."

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User comments : 22

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cantdrive85
1.3 / 5 (12) Sep 25, 2012
The idea of a liquid ocean is more likely a misunderstanding of the observations and data than a real possibility.
Ophelia
4.4 / 5 (7) Sep 25, 2012
The idea of a liquid ocean is more likely a misunderstanding of the observations and data than a real possibility.


because ....
rkolter
not rated yet Sep 25, 2012
The last I had read, which admittedly was several months ago in a Discover or Science News was that the most likely scenario was frozen ice all the way down with pockets of liquid water where the tidal stresses were strongest. Has that changed, or am I simply remembering wrong? I'd be thrilled to "know" that there was a mood-wide liquid ocean, albeit very deep.
cantdrive85
1 / 5 (10) Sep 25, 2012
The idea of a liquid ocean is more likely a misunderstanding of the observations and data than a real possibility.


because ....


http://www.thunde...uropa-2/
Jonseer
4.6 / 5 (10) Sep 25, 2012
The idea of a liquid ocean is more likely a misunderstanding of the observations and data than a real possibility.


If anyone is is guilty of poor conclusions re Europa its the guys at thunderbolts, and I'm not foe of the electric universe.

I am a foe of gross self deception however.

The markings on the aluminum ball they subjected to the type of electrical phenomena they say is responsible for the surface markings on Europa do NOT match. They look NOTHING like what we see on that moon.

They claim the broken ice plains on Europa resemble nothing on Earth. Oh really.

They resemble Antarctica and the Arctic ocean perfectly when frozen over.

Yet somehow they think they do. Talk about wishful thinking.

In any case the assumption that there is an ocean beneath the ice is a conclusion drawn from multiple sets of data not just surface markings.
Lurker2358
2 / 5 (4) Sep 25, 2012
Well, given the albedo of 0.67, and the solar constant at that distance you'd actually expect Europa's surface temperature to be around 5 kelvin.

So it's definitely being heated by radiation (internal and/or external,) and/or tidal forces.

marble89
5 / 5 (3) Sep 25, 2012
The evidence for a global ocean under the Europan ice is overwhelming and comes from many independent disciplines. The only serious debate is how thick the ice is. Here we have conflicting observational evidence. The few sizable impact craters argue for a 10-20km thickness but the areas of chaos argue for a much thinner ice thickness. Until we know the chemistry of that ocean and know what the geothermal/tidal heat flux is we cant constrain the models - we need more data. Given this I applaud the authors on coming up with yet another scenario that is consistent with known facts.
cantdrive85
1 / 5 (9) Sep 25, 2012
http://www.nasa.g...full.jpg

So this looks like cracking ice? Notice the numerous "cracks" that bisect the others, notice the morphology of those parallel "cracks". If you really think that looks like ice, I think you need to get off the "cracks" pipe.
marble89
3 / 5 (2) Sep 25, 2012
Lurker: The calculated and measured surface temp of Europa agree very well: 110K /-10 globally. NOT 4k - nothing in nature is that cold.
The only plausible source of heat sufficient to maintain the ocean is interior tidal ( look at IO) or possibly tidal friction within the ice itself
marble89
4.3 / 5 (6) Sep 25, 2012
Cantdrive: If you take a moment to google it you will find that the large scale cracks are well understood and have been reproduced by a number of tidal stress models in impressive detail. All models require a liquid layer beneath. AGAIN - yet another line of independent thinking that points to an ocean
mrpiano
5 / 5 (4) Sep 25, 2012
Silly boy, just about everything in the Universe is electrically neutral. Plasma Cosmology never made it out of the 60's.
cantdrive85
1 / 5 (9) Sep 25, 2012
Piano, being that over 99% of the visible Universe is composed of electrically charged plasma, that is quite a ridiculous statement. The notion the the Universe is electrically neutral was quashed as soon as we started sending probes into space.
cantdrive85
1 / 5 (10) Sep 25, 2012
Marble, I see grooves, and very little that could even be considered cracks. You can see many instances where the grooves intersect and you can see the material being pushed up on both sides of the groove. In the image I link to above you can see where some of these grooves swirl, there's also at least on instance of a crater chain being carved out of a section of a much longer existing groove. EDM is a much more plausible explanation, especially considering the charged body of Europa is immersed within Jupiter's plasmasphere.
LED Guy
5 / 5 (2) Sep 25, 2012
Cantdrive, the particles that make up a plasma are charged, but taken as a whole plasma is electrically neutral. As you have pointed out here, electromagnetic forces are huge compared to gravity. If you had a plasma that was composed entirely of positive (or negative) ions, the electric fields would be enourmous and the attractive forces on nearby oppositely charged particles would draw them in to give a net neutral collective.
cantdrive85
1 / 5 (10) Sep 25, 2012
Plasma cannot be considered "as a whole", it is the interaction of the individual ions, neutrals, and electrons that create the filamentary and cellular aspects of plasma, just as has been discovered. In space plasmas retain their charge, the exception are terrestrial bodies where the "hot" particles are able to sufficiently "cool" into the solids, liquids, and gases we are familiar with.
LED Guy
5 / 5 (1) Sep 26, 2012
Do us all a favor and look up Eddingtons comments on the "mass" of a gram of electrons. Confine them to a region with a radius of 10cm. Just electrons, nothing else.

Hint if you take into account the electrostatic potential energy of this much pure charge then energy equivalency gives you an answer in millions of tons. You would also have a bomb orders of magnitude more powerful than the world's entire nuclear arsenal.
cantdrive85
1 / 5 (7) Sep 26, 2012
Plasma creates an electrodynamic relationship with the other particles, not electrostatic. And I can't imagine what that hypothetical statement has to do with anything at all.
cantdrive85
1 / 5 (8) Sep 26, 2012
The important thing to remember is that there will be areas of different potential WITHIN the plasma, this causes the plasma to flow and constrict into the filamentary and cellular patterns. The sum of the whole maybe neutral, but the ions, electrons, and neutrals that comprise the space plasma dictate that electric currents will be generated.
DaveMart
not rated yet Sep 26, 2012
How long an individual pool of water relatively close to the surface lasts does not matter too much if they are regularly produced due to tidal stress.
Parsec
5 / 5 (1) Sep 26, 2012
The idea of a liquid ocean is more likely a misunderstanding of the observations and data than a real possibility.

And you base your conclusions on what?
Torbjorn_Larsson_OM
5 / 5 (2) Sep 26, 2012
The unambigious observations of an underlying ocean is due to the constraints of the tumbling ice floes that fresh rough terrain on Europa tests. Kalousová's work doesn't seem to touch this but confirm it (thin ice; near surface water pockets).

The EU/PC belief (eg cantdrive85) is more pitiful than ever. Besides not having a clue, they don't bother to make up references. We expect at least one mentioning of their religious founder Hannes Alfvén, at least one obeisance by the altar of Birkeland currents, and at least one commandment deliverance of "plasma, not gas".
marble89
3.7 / 5 (3) Sep 30, 2012
Remember: DO NOT FEED THE TROLLS