I've done a little reading, and it turns out that the standard (3-layer) theory of the Jovian internal structure is that there is a rocky, "icy" core surrounded by a higher-density monoatomic hydrogen mantle that is in turn surrounded by a gaseous/liquid phase layer consisting of molecular hydrogen (I guess the gas is pressed so densely, there's little use in making that distinction). The transition between the atomic/molecular layers is called the "plasma phase transition" or PPT.

Depending on who you read, the radius of the PPT boundary zone varies from 0.9 R_J to perhaps 0.75 R_J, where R_J is Jupiter's radius. This works out to a PPT depth of something like 7,000 km to 17,000 km.

Now, at its narrowest, the GRS is about 12,000 km to 14,000 km across. Thus, if the GRS is as deep as it is wide, it could easily reach the PPT.

If the GRS were a low pressure system, it could locally lower the pressure of the PPT. This would allow atomic hydrogen to recombine to form molecular hydrogen. Since it takes energy to split apart a hydrogen molecule, energy will be released when two, lone hydrogen atoms recombine; according to the law of gases, the added heat (and the newly converted molecular hydrogen) would cause the local density to decline, thus causing the material to rise. This is literally a form of combustion, and is what powers the GRS heat engine.

That is why the GRS is the best vortex in the solar system: it is able to "mine" its own energy. The reason hurricanes and tornados eventually peter out is that the supply of warm, low level air dries up. The GRS makes its own warm, low level air.

The effect is rather analogous to those so-called killer lakes in Africa. At Lake Nyos, in Camaroon, the lake is stratified, with the bottom layers loaded with dissolved carbon dioxide, like so much club soda. Occasional eruptions have caused the deaths of hundreds of people. So, in order to reduce the danger, it is possible to tap into the bottom layer with a pipe. A pump then lifts the low level water; as the pressure declines, the CO2 is released, and the flow takes on a life of its own and sprays out like a shook up champaigne bottle (see attachment).

Again, this episode demonstrates that looking at some physical systems as if they were alive can sometimes produce results faster than trying to approach the problem from first principles. Thinking about the GRS as an animal made me focus on its "needs" and hence to wonder what it "eats". Watching the videos, it was clear that cannabalism provided marginal nutriments at best. Thus, the GRS must be "eating" something else. This provoked me to consider other sources of energy, and was eventually able to deduce that the GRS was tapping into the PPT--the GRS is a plasmavore; trying to deduce this same conclusion from the equations of fluid mechanics is a nonstarter. And tapping into the PPT will only work if the GRS is a low pressure system--which it simply has to be because high pressure systems are poor designs for storms.

Skim to post #37

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I'd always heard that one of the theories of the GRS was that it was a Taylor column.

What results? You have a hypothesis that does not appear to be inconsistent with observations, but it has yet to be experimentally verified. I would say it's a bit too early to be patting yourself on the back about the efficacy of your teleological methods.

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I've reported this post as a copyright violation. While Wikipedia allows the reuse of their articles elsewhere, proper credit must be given per the license the website operates under.

Further, it's a lot easier to just link directly to the version of the article you want to point out using the "Cite this article" link on the left hand side of the page. That will give you the scholarly citation formats, as well as a "permanant link" to that version of the article.

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Actually, CodeSlinger, except for this:

WarrenPlatts hit the nail on the proverbial head.

Yes, it might be able to mine it's own energy, but eventually, due to friction of the currents, that will die out, just as without a steady supply of CO2 from underground sources to the lake he mentioned (cool, Warren, as was their solution to the problem), the lake would, after one final eruption, become placid.

So, Jupiter's second and third layers are getting their energy from somewhere... Perhaps just the sun, like we all do?

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If I set the budget, we'd have Ares and more. Unfortunately, I don't set the budget, and Ares is just too expensive and too far out for us to accomplish our goals within the budget we were given.

If we halt the ISS, all versions of Ares, and transport Orion and Altair aboard DIRECTv3's Jupiter family of Shuttle-Derived Launch Vehicles, we just might make it back to the Moon by 2020.

Sorry mugaliens, but please explain what proverbial nail you think WarrenPlatts has hit on the head.

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That's interesting, because I was having a hard time imagining what a high pressure storm would be like. But a Taylor column (a vortex that forms over a solid object moving through a rotating fluid) might possibly provide a mechanism for a real high pressure storm system, especially if the obstacle were some sort of plasma volcano or geyser-like object: a plume of hot plasma could provide a source of energy and matter that a high pressure storm would require, and would account for the fact that the GRS pokes out of the surrounding cloudtops by about 8 km.

But apparently, the Taylor column hypothesis has fallen out of favor. The literature on the Taylor column hypothesis peters out in the late 1970's, probably because of the radio data that has pinned down the rotation of the interior of Jupiter:

(NASA/World Book Encyclopedia)

Observations of both radio waves and the GRS are the sorts of things that can be precisely timed from Earth. The result is that it is now known that the GRS migrates slowly to the west, relative to the interior--in the same direction as Earthbound hurricanes.

One could argue that the obstruction causing the GRS isn't fixed to the solid interior, and so could also be drifting in a westward direction, and so the GRS is merely tracking the movement of the obstruction. However, the Coriolis effect tends to make westward moving objects in southern hemispheres move to the south. On Jupiter, however, vortices maintain a steady latitude for the most part presumbably because they are confined by the powerful jetstreams prevalent there. It is less clear that analogous mechanisms would prevent an object floating in the interior from moving to the south.

Finally, according to the Taylor hypothesis, if the GRS were the result of a hidden obstruction, it would have formed as one single system, whereas I hypothesized that the red spot was the result of the fusion of two or more smaller spots. Well, the recent Red Spot, Jr. that is about 1/2 the diameter of the GRS was directly observed to have formed from a fusion of three smaller spots at the turn of the century, indicating that the general mechanism for the formation of large spots is through the fusion of smaller spots. This result is also supported by physical analogue water-tank experiments in the laboratory.

So, so much for the Taylor column hypothesis.

Anyone else want to step up to the plate?

Skip to post #42

I thought the Spot's longevity was tied to the fact that it has nothing to expend energy against, like a continent.

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I'm not sure what you mean by "proper credit must be given per the license the website operates under." What license and what website are you referring to? If it is wikipedia.com, they make the terms of use perfectly clear:

Trademarks and Copyrights
Wikipedia: CopyrightsTherefore, I plead not guilty to the charge of violating U.S. copyright law.

This, however, is useful. I did not know how to do this before. Thank you.

Wind shear would have destroyed the GRS long ago if it did not have an outside energy source.

You'll want to go back and fix that post then, a mod has already removed the article from your post.

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Well, as I've said before, Jupiter is a pretty big planet, and so it might take a while to deplete the plasma mantle. There are signs, however, that this may be already happening, since the GRS has declined in size by half over the years since its hey-day.

Probably, what happens is that the GRS and spots like it suck monoatomic hydrogen out of the plasma mantle, convert it to dihydrogen, and then spread it through the atmosphere, causing the depth of the plasma phase transition zone (PPT) to get deeper and deeper. Meanwhile, elsewhere, in areas of comparative quiet--the vast majority of the rest of the planet--the plasma mantle is slowly recharged as pressure and temperature do their work to dissociate molecular hydrogen.

Thus a dynamic equilibrium situation will be set up. Red spots suck out monoatomic hydrogen causing the PPT to sink. Counterbalancing this, as the PPT sinks, it becomes harder for red spots to suck out monoatomic hydrogen, so that the red spots decline in size and perhaps disappear altogether, and thus the rate of depletion of monoatomic hydrogen from the plasma mantle declines. Meanwhile, as the sea of dihydrogen follows the sinking PPT, the pressure and temperature increase, thus the rate of dissociation also increases, further slowing the rate of increase in depth of the PPT. As red spots decline, the rate of deposition of monoatomic hydrogen outpaces red spot outgassing and the PPT begins to rise again.

Probably, this process is a cycle that may take several hundred years or more. There might have been periods in history where there weren't any Red Spots, corresponding to a relatively deep PPT. At other times when the PPT was shallow, there were probably more Red Spots than we observe now.

Supposedly, Jupiter emits something like three times more energy than it receives from the sun. Presumably, the ultimate source of this energy is from radionucleotides, as on Earth, gravitational collapse Lord Kelvin-style, and I would guess the occasional fusion event would add some heat, but not enough to start a chain reaction. (cf. Deuterium burning in Jupiter interior, 2001)

It is this heat that ultimately drives the red spot cycle by keeping the temperature of the interior of Jupiter hot enough to cause dissociation of molecular hydrogen into monoatomic hydrogen. If these heat sources were to decline in intensity, what would happen is that Red Spots would depress the level of the PPT until the red spots could no longer function normally. However, because the interior had subsequently cooled, the conversion of molecular hydrogen to monoatomic hydrogen would no longer be thermodynamically favored. Eventually, you would wind up with a Saturn-like planet with a weak magnetic field and no red spots.

Skip to post #43

My result is a concrete hypothesis, that, try as I might for many hours of googling every which way but loose over the last two days, apparently no one else has thought of; but it is so obvious to me, I'm 90% sure that someone else must have thought of it first and that it is out there somewhere.

As for experimental verification, if you won't be satisfied with anything else other than a NASA probe that can fly into the eye of the GRS, dive down to a depth of 10,000 km, and then survive to tell us what it's like down there, well, that's just unreasonable to expect.

But consider the following: my model says that big spots form by cannabalizing little spots, but also that once they achieve a certain critical size, they will be able to locally take the lid off the pressure cooker that contains the PPT, thus gaining energy, but also changing the spot's chemical composition such that it turns red.

Similarly, the Red Spot, Jr., formerly known as the BA spot was formed originally from three medium-sized white spots that fused together from 1998 through 2000, to form one pretty big white spot. Then, in December of 2005 the BA spot turned red, and then became known as Red Spot, Jr.

Now this is just the sequence of events my model predicts. Indeed, I hadn't followed the saga of Red Spot, Jr. in the news over the last few years, and only took the time to read very much about it this very afternoon. Yet, yesterday, I wrote:

So, in my own mind, I have made a successful prediction. However, I don't expect you all to take my word for that--that's OK. Too bad I didn't think all this up in November of 2005--it would have been perfect! Oh well.

But in any case, the low pressure system model for the GRS does successfully retrodict the formation and transformation of the Red Spot, Jr.

Skip to post #47

It's no big deal.

Sorry, but as far as I know, a hypothesis is not a result.

On the other hand, while retrodictions are not as good as predictions, your retrodiction of Red Spot Jr. is pretty cool. Can you take it further? Does your model predict or explain anything the mainstream model does not?

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Taylor Columns and more

http://en.wikipedia.org/wiki/E%C3%B6tv%C3%B6s_effect
http://journals.cambridge.org/action...ine&aid=370125

The mainstream model as I understand it is that the GRS is a high pressure system powered by an "unknown mechanism" in contrast to common low pressure systems, such as hurricanes or tornados. The high pressure hypothesis does explain the anticyclonic rotation in the sense that high pressure air usually rotates in an anticyclonic manner, and the 8 km rise above the cloud deck. The best mechanism proposed so far consistent with the high pressure hypothesis is the Taylor column hypothesis--whereby the GRS is tied to a plasma-emitting volcano.

The low pressure hypothesis, however, naturally explains the following:

1. the anticyclonic rotation (it's the upper part of a low pressure system)
2. the rise above the cloud deck (just like all hurricanes)
3. the origin of large spots through fusion of small spots (the GRS is the result of an evolutionary process)
4. the transformation from white of Oval BA to the red of Red Spot, Jr. (Oval BA got big enough to tap the PPT--this changed its chemical composition)
5. the source of energy that powers the GRS (combustion of monoatomic hydrogen)
6. the decrease in size of the GRS (increasing depth of the PPT as a result of resource depletion)
7. the migration of the GRS relative to the interior (it's a hurricane, instead of a Taylor column tied to a fixed spot)
8. the mass required (part of it comes from the plasma mantle)
9. and probably a few others

Skip to post #51

Interesting stuff. How great is the migration? I couldn't find any figure other than the 9h 56m one, or at least one significantly different.
Nonfixity of features, and differential rotation is an immense problem! Fun.
If there were associated interior features, it would seem that those would be forming as well, perhaps creating eddies that coalesce as they grow.Yes, I'm wondering about this. If there is no interior feature anchoring the system, wouldn't its velocity be much greater? Earth hurricanes fairly skitter across its surface, (solar features like sunspots do too--even though the sun rotates so slowly--but the solar problem seems to be a different regime.)

I found a figure for 9h 55m, but that doesn't make any sense if it's actually drifting westward. BTW, Red Spot, Jr. is moving to the east, and they passed each other in July 2006, (see photo from Keck observatory) but they didn't interact much.

I could see how the entire mantle could be twisting such that the GRS would have an apparent drift to the west relative to the radio source that might lie much deeper. However, this wouldn't account for Red Spot, Jr.'s movement (nor the fact the Oval BA was directly observed to form from three smaller spots; surely, we wouldn't want to think that there were three smaller unseen objects that then coalesced, and that this new object is moving in an opposite direction to the object driving the movement of the GRS.)

According to the low pressure hypothesis, the GRS is tied to an interior feature: the plasma phase transition zone (PPT). I envision the PPT as being fairly flat, but the GRS is pumping out so much monoatomic hydrogen that it has dug itself into a hole. Thus moving fast would require the GRS to move uphill. Instead what happens is that the GRS is in effect forced to "plow" its way through the PPT, and this accounts for its slow motion relative to the radio source.

That would be the GDFL, which you quoted in your post. Just like the license many Linux programs operate under, anything released under the GDFL must also be released under GDFL, including a copy of the license. You could re-use snippets of the article (per fair use), but reposting the entire article requires adhering to the GDFL.

It's a technicality, but unfortunately you did. No harm done, but I thought it best to clarify. Part of the problem is there's a copyright conflict when posting to message boards. I do believe on here, the BA has stated that all posts are copyright their authors, but on others the board owners themselves claim copyright to your posts. That would be a problem with the GDFL.

No problem! Most folks miss that, as it's not exactly going to stand out on Wikipedia's pages. It's one of their most useful features, though.

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The Little Red Spot (a.k.a. Red Spot Jr., or Oval BA) has increased in wind speeds to those comparable with the Great Red Spot (up to 400 mph), according to 2006 Hubble Space Telescope data, whereas the parent storms had maximum wind velocity of 268 mph as measured by the Voyager probe in 1979.

NASA scientists are at a loss to explain this apparent increase in wind velocity:

The low pressure model neatly explains the increase in strength of the new spot, however, as a result of gaining a new energy source by tapping into the plasma phase transition zone.

And although the team mentioned in the above article states that the increase in storm power could explain the the change in color from the white Oval BA to the red Red Spot Jr. as a result of dredging up deeper material, they don't say why we should expect that deeper material should result in a radical color shift.

According the the standard 3-layer model (core, metallic envelope, molecular envelope), there should be little mixing between layers, but the layers themselves should have fairly uniform chemical compositions due to mixing by convection. Therefore, if red spots are not tapping into the PPT, there is little reason for them to be red because the standard, mainstream model predicts that the molecular envelope should be well mixed. But if red spots are able to tap into the PPT (practically by definition, according to the low pressure model), the change in color is not surprising and is indeed expected.

Skip to post #54

At this point, I must plead ignorance and bow out. I simply lack the knowledge to evaluate whether those items really are unexplained by the high-pressure hypothesis and explained by the low-pressure hypothesis. Hopefully someone more knowledgeable can comment on these.

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Gotta applaud Mr. Platts on this one. Take note, folks, this is how you present an ATM theory. I definitely like how this is being done.

Thank you, Mr. Earl!

It would be nice if there was seismic evidence that would shed some light on the interior of Jupiter. Global Jovian oscillations should reveal information regarding the structure of the interior. But I gather its not that easy.

Lacking direct seismic data, inferences about what the interior of gas giant planets are like are based mainly on the primary considerations of mass and radius, as well as the primordial mix of basic ingredients.

Equally important, are the thermodynamic equations of state for hydrogen, helium, and hydrogen/helium mixtures. These EOS's say what the density of hydrogen should be for a given pressure and temperature.

Thus, if you knew that Jupiter originally consisted of 27% (by mass) helium and 72% hydrogen (with 1% heavier elements), then if you also knew that the atmosphere of Jupiter (as directly measured by the Galileo probe) was only 24% helium, that would warrant the inference that helium was settling in the interior of Jupiter somehow.

However, for Saturn, the best estimate returned by Cassini is a mass fraction for helium of 18% to 25% (Gautier et al. 2006). (In the gas giant literature, one will commonly run into constructions of the following sort, where 'X', 'Y', and 'Z' refer to the mass fractions, percentage-wise of the constituents of a gas giant, of hydrogen, helium, and heavier elements, respectively; hence, Gautier et al. write "helium mass fraction of Y 0[.]18-0[.]25")

Now, if red spots are really tapping into the PPT, then red spots are bringing material from beyond the PPT into the molecular envelope zone. So, possibly, red spots on Jupiter-like planets might slow down helium sequestration by pumping material from the metallic zone into the molecular zone. This might explain why atmospheric Y on Saturn is apparently lower compared to Jupiter--Saturn doesn't have red spots as a mixing mechanism.

Skip to post #78

I was just perusing the wiki article about the Great Red Spot and clicked on the Mechanics section. It's first sentence says "As the hot gases that comprise Jupiter's atmosphere rise from lower levels to higher levels, eddies form and converge. A Coriolis force forms and forces cooler air to fall back into a swirling motion that may be many kilometers in diameter." Is that similar to what you are saying?

This paragraph, at least, of the Wiki article is poorly written.

The first sentence is innocuous; but as for the second, the Coriolois "force" isn't a real force, therefore, it can't "form", and it can't "force" anything. Furthermore, it isn't informative to call a storm a mere "eddy" (cf. Phil Plait's interview with Pamela Gay re: Jupiter). Moreover, the article implies that only solid surfaces provide friction. However, wind shear in any substance with a viscosity greater than zero will "provide friction"; hence the requirement for continual energy inputs. Then the "It is theorized that this mechanism formed the Great Red Spot" isn't clear; which mechanism is "this mechanism" referring to? And in any case, I've explicitly argued that swallowing other storms does not at this point in the GRS's lifetime explain its continual persistence. So, to answer your question hhEb09'1, I deny that there's much affinity between the Wiki article and the theory I'm trying to present here.

Yes, I'm persuaded. Anybody have any testing ideas?

IIRC, a long time ago, maybe 30 or 40 years, some researchers took a large flat tub, cooled the center, heated the edges, and rotated the whole business. And repeated the process many times. Most of the time. a large stable vortex formed at approximately the red spot latitude. I have no idea if it was a low or a high, but it might be in the literature somewhere.

Good job, Warren.

One way to test the hypothesis would be to send an atmospheric probe into the Red Spot itself. If the GRS is in fact driven by latent heat released by material liberated from the metallic envelope, then one would expect the GRS to be enriched in helium and perhaps other heavy elements (e.g., neon), relative to the rest of the observable atmosphere.

As it is, quantitative analysis based on spectrographs is not a very exact science (as was shown by the Galileo probe that corrected upward previous Y (helium) mass fraction estimates based on spectrographes.)

One thing I find inexcusable is that we go to all this trouble to send a school-bus sized probe to Saturn, but don't include an atmospheric probe to directly measure the atmospheric composition. As a result, the Y of Saturn's atmosphere can only be pinned down to between 18 and 25.

Just have an Ares V or two launch this to Jupiter:

http://www.merkle.com/pluto/pluto.html
http://www.designation-systems.net/dusrm/app4/slam.html

And outfit it like this:
http://en.wikipedia.org/wiki/WP-3D

That would be cool. It would be nice to get actual transects from across all latitudes. But how about a nuclear powered dirigilble? It would be able to last even longer than the ramscoop ship, but it might not be able to handle the turbulence.