All...

this IS very bizarre.............. if I saw this on a science fiction depiction of a planet I would discard it as bad science....

http://saturn.jpl.nasa.gov/news/press-rele....cfm?newsID=735

WOW!

Craig

Ah yes! This undoubtedly proves that Saturn's core really is one giant dodecahedron of iron pyrites! Known as the 'Abode of Time', this is where the souls of great mathematicians exist in a quantum stasis so perfect that it will outlive the Universe . . . .

Neat stuff, though why, for the love all that is good and holy, are the full-sized images enlarged so much?!? These are only 64x64 image cubes, yet PIA09188 is expanded to 15750x13717.

May be time for Doug to ban all Cassini threads--seems JPL has gone over the the dark magic side

Been a long day and am finally relaxing with a couple beers, so excuse the rambling....

Seeing something like this almost makes me wonder if Cthulu is going to erupt from the hexagon to eat CASSINI.

This is a bit spooky but of course perfectly natural (because, if it happens, it's part of nature.... ).

Is anyone out there familiar with fluid dynamics? Just seems to me that STABLE geometric patterns in fluids (which includes the action of gas molecules that are densely packed together) is almost unheard of...... this feature was also observed by one of the Voyager spacecraft.... so it is long lived. But I am certainly NO expert.

The Saturn system is seething with mystery.
From the northern hexagon to the south poles central whirlpool. The wonderful dance that is the rings and it's tempy mooms....The tiger stripes of Enceladus and the geysered ice ring that grabs Saturns magnetic pull to pattern it's beat by this moons tempests.... out beyond the bounds of the cratered ice cube that is Mimas, cracked Tethys and wispy Dione, old man Rhea next to the majestic world that is Titan, young and wrapped in mystery, seeding a nitrogen torus that licks at Hyperion, the broken, eternal tumlbing pumice ball, an event related to the piebald Iapetus and it's central Himalayan bulge?

How wonderful a piece this is to try and decipher. What wonderful new things will we learn?

Craig

I knew I had seen something like this before:

http://arxiv.org/PS_cache/physics/pdf/0511/0511251.pdf
http://www.physorg.com/news66924222.html

googled: fluid rotation wave polygon

I sent Dr. Bohr an email to ask him his opinion on this. They didn't mention it in their original article. Maybe they didn't realize a hexagon had been seen on Saturn during the Voyager flybys??

...indeed...that's cool, hendric!!! How odd and how beautiful that a complex (chaotic!!!) phenomenon like fluid dynamics can mutually interact in probability space in such a way to produce minimalist geometric forms perceptible to our senses...fascinating and profound on many levels. Mathematics really does rule the Universe despite quantum and particulate uncertainty, nicht war?

Bad joke warning: Clearly, Saturn got a hexagonal tattoo to reflect its pride in being the sixth planet, and also to warn others that they're in its' 'hood... (I live in LA, so I think like that... )

Fantastic recall hendric. You get the prize for the day.

Thanks for the references, Hendric. I sent the references to some of the Huygens scientists, who were quite interested in them. Everyone still seems to be in the head scratching phase at the moment.

-Don

I hope linking to this is not considered blasphemy.

Doug: Yes - it is.

Excellent hendric!!!!!!!

Now how does that translate from the laboratory into nature....what's confining the sides to hold the symmetry?

Craig

Probably due to pressure from print publications. I remember having to produce a Venera-13 pan that would be something like 6 inches tall and God knows how many inches wide at 300 DPI! I tried to explain that the image couldn't support that resolution, but they couldn't grasp that concept.

Maybe the magnetic field?

polygonal patterns of relative vorticity develop in the vortex core of hurricanes. The same principles at work?

First of all, I have to apologize for having a rather poor memory, so some of this may be a bit off. It seems that I remember seeing multiple hexagons in some Mariner 10 images of Venus' atmosphere (probably UV). The explanation was that these were convection cells bringing heat from the lower atmosphere almost vertically to the upper atmosphere (implying low or no shearing winds). There was also a Scientific American article some years ago showing an array of bordering hexagons transporting heat in some fluid. This is supposed to be the most efficient way to transport heat in a fluid/gas.

Good thought!!!! If that is the confinement, WOW...an honest to goodness electrodynamic confinment field??? Fusion guys should look into this.

hendric..... you should send those links to Kevin Baines of the VIMS team.

Also ..... huge note of embarrassment in previous post " old man Rhea next to the majestic world that is Titan"..... Rhea was actually the Mother of the gods.... not an old man, but I will blame that on several beers and it just sounded better than old gal Rhea....

Craig

From a maths poster in the London Underground:

http://www.newton.cam.ac.uk/wmy2kposters/f...02stirs025f.jpg

This is interesting in view of what I noticed when I reprojected my simple cylindrical mosaic of the southern hemisphere to show the south polar region:

http://www.unmannedspaceflight.com/index.p...ost&p=79263

("Another feature I find especially interesting is that a part of the belt/zone boundaries near 60°S looks like the famous hexagon near Saturn's north pole. However, this is only a partial polygon...")

This may be too indistinct to be a real feature but I still wonder if it is.

I think it's extremely unlikely the magnetic field has anything to do with the hexagon. Looks like fluid dynamics at work.

I did a little googling, and there is something called Rayleigh-Benard convection that creates nearly perfect hexagons in a fluid with very low or no turbulence. It typically forms arrays of hexagons, so I don't know the significance of a single hexagon. Perhaps this is an "island of stability" in an otherwise turbulent Saturn atmosphere. The center of a hurricane analogy mentioned may be quite apt. It might be worthwhile to take a close look at the area around the hexagon.

Bjorn, I wasn't saying that the magnetic field was responsible for the hexagon, I was hypothesing that it could somehow work as the container as in the studies for which hendric provided some links.
In the image attached you can see what I was referring to:
Click to view attachment
As usual I'm out of my field here too...

BAD QUOTING - STOP IT - Doug

Interesting idea. Is the Saturn magnetospahere mapped well enough to know where the poles are? Are the magnetic poles almost at the geographic poles, like they are on Jupiter and aren't on Earth? Is the north magnetic pole near the north geographic pole, but the south one not near the south pole, and therefore you get a hexagon on one side and not the other?

If I understand where this discussion is going Saturn in its entirety is the container - in particular you do not need a container around the polygon itself. And I fail to see how a magnetic field would be supposed to affect cloud structures this way. There is a very strong zonal wind gradient at the latitudes of the hexagon and the hexagon itself is embedded in an eastward jet.

Saturn's magnetic axis is nearly identical to its rotation axis.

My knee jerk grasp for a mechanism made me think it's also some manifestation of the magnetic field, but like kwan said, how can you explain other plantery magnetic poles on gas giants don't produce the same features, and why is saturn's other magnetic pole not symmetric?

The convection cell theory sounds interesting, but for something to be stable for 25 years is amazing... and why is it only at one pole, and why don't other gas giants have them? Weird.

Ustrax, I dont see any reference made to influence from a magnetic field in the paper called :Polygons on a Rotating Fluid Surface. Could Magnetic fields be strong enough on the scale of a cup of water?

I can see the headlines now:

SATURN'S AMAZING HEXAGON IS A STORM IN A TEACUP

I second the weirdness of the subject...
One thing coming to my mind is a...Black & Decker drill...
Of course this implies that both poles had to be connected...
See the hexagon? That's where the drill entries...
The south pole hurricanes?...What happens when your screw reaches open space?...

Please, just forget I wrote this...

zoost, I've don't have the slightest idea...

EDITED: ngunn...

This post on Space.com may be helpful.

Benard-Marangoni...That is exactly what I was trying to say!...
Thanks centsworth_II

That's what I suspect too. I remember when I went through the finish stages of writing my chapter for the "Io After Galileo" book, and was asked to provide a higher resolution version of a color map that combined images from the first two Galileo orbits. I told them no, the image I provided was as high as I could make it, they would just have to accept it as is. And they did.

OK, just did so, but I would guess he would already know about some of these since they occur with hurricanes and he's an atmospheric scientist.


1. Why Saturn, but not the other giants?
Maybe because Saturn is a fast rotator, with a significant tilt, thick rings to cause oddball heating, and is the most oblate? Or is that answering the question with "Because it's Saturn!"

2. Why the north, but not the south pole?
Could Saturn's relatively high eccentricity be a cause? Could someone with a simulator determine when Saturn is closest/furthest from the sun, relative to its axial tilt towards the sun?

It seems like the VIMS team is seriously looking at this research. One of the local networks did a story on the 10pm news on the north polar observations and after they showed a bit of their interview with Bob Brown, they spent a bit on this fluid dynamics research as an example of what the VIMS is looking into for the origin of this odd feature.

Along with hendric's e-mail, on yesterday's afternoon, I've also sent an e-mail to Angioletta Coradini, from the VIMS team, about the issue, so I guess they must be drowning in all this fluid stuff by now...

Yep, Kevin seems to agree:

hendric...

this makes things even more interesting..... laboratory demonstrations do not always
apply in the larger world of open nature. But VISUALLY that sure looks like a dead ringer.

And WHY are Saturn's poles so different..... and what is special about Saturn that we see a hexagon here and no where else?

Pioneer 11 bolted over Jupiter's north pole and saw nothing like this. Voyager 2 swooped by Uranus while it's pole was pointed to the Sun and then went on to glide over Neptunes north pole. Nothin like this was seen.

What a puzzle ....

Love it!!!!!

Craig

A puzzle indeed! (How can anybody not love UMSF and exploration, I ask you?)

Well, just for sake of keeping the juices flowing here, it's interesting that Saturn's north pole exhibits a behavior close to a model that apparently utilized a homogeneous (in terms of properties) fluid medium at least as far as viscosity, etc. The 25-year interval between observations means that we're seeing the north pole at almost the same point in Saturn's orbit as before (29 year orbital period).

Therefore...I think Hendric may be on to something with his seasonality. Something might be getting preferentially cooked out of Saturn's upper atmosphere due to prolonged exposure to sunlight (ammonia condensates or some organic?) Whatever it is, when it dissociates or melts the atmosphere gets a lot more 'uniform' with respect to fluid dynamics, and a hexagon is born.

Seems as if there might be another competing (or perhaps complementary?) objective for the extended mission. Can we watch both Titan & Saturn's polar regions over time given the right orbit?

How about an orbit inclined 90 degrees to the ring plane that goes out past Titan? Go over both poles of Saturn every orbit, and Titian too if synchronized.

I would just note here that if we want an extreme example of seasonality in a hydrogen dominated upper atmosphere.... just look to Uranus.

There was a proposal a few years back to launch a second NH type spacecraft to do another Uranus flyby before it sailed into the Kuiper belt.... sort of a NH backup, but no Pluto encounter.... too bad that was never
picked up..... but then if we are looking to see seasonal effects from a long winter we would need to look in again about a hundred years from now.

Again Hendric.... good find....

Craig

The hexagon has been visible to HST in all cases when the north polar region was in view (for example in the early 1990s) so the hexagon probably has been there continuously for about 30 years or more.

No hexagon has ever been seen in the south polar region. However, as previously noted I noticed hints of an incomplete 'polygon' in the south polar region when reprojecting a cylindrical map to view the south pole from 'below'.

For all we know, the hexagon might be as old as Jupiter's GRS. Makes you wonder which of the two is a more stable configuration. I didn't have time to check out the paper mentioned here, but is it conceivable the hexagon is actually more stable since it's on the pole and so safer from disruptive turbulences ath the belt/zone boundaries?

I'm wondering whether there are any animations from Voyager that show the hexagon?

I haven't heard of Benard-Marangoni convection before (hope that's the right spelling), but, for the sake of argument, let's assume it's the responsible mechanism.

There's a fluid-dynamical quantity called (I think) the Reynolds number, which relates scale, viscosity and time. Basically, if two fluid systems share the same Reynolds number, they can be expected to behave in roughly the same way, even if their scales are very different.

I'm no expert on fluid dynamics, but just for a starting argument, if the wafer-physics experiment described by Buddy from Space.com has a similar Reynolds number to Saturn's upper atmosphere, and if the geometries involved can be thought of as being anywhere near similar, then maybe he's got something there.

I don't know about this, though. A rotating silicon wafer with a few drops of fluid on it is awfully different from a gas giant planet. Saturn's got no solid surface, right? So it's a very weak analogy.

The "standing wave" idea seems much more reasonable. But, like I said, I'm no expert here.

yes that's the Reynolds number. But there are some more of these quantities that may be important (e.g. http://en.wikipedia.org/wiki/Prandtl_number). But I'm not an expert myself either.

Saturn's vortex.
Saturn's vortex - wide angle camera.
Saturn's vortex - narrow angle camera !
I love this spacecraft.

That's actually the south pole vortex, not the north pole hexagon.

All....

north polar hexagon edging into view.... love all those little vortices crowding around. Looks like an airflow from the south may be feeding this (or fed by it). Lovely...

http://photojournal.jpl.nasa.gov/catalog/PIA10449

Craig

Is that bigger one at lower center an upper level low (sucking downwards) or an upper level high (pumping upwards)?

-Mike