Saturn's Strangest Spot

[MetalMario]

Today I watched videos on HistoryChannel like I do every day. Upon watching a video about Saturn, I learned something interesting. There is some sort of hole on Saturn's North Pole. It is shaped like a perfect Hexagon. Now, we all know that in space, astronomy, and the universe, that nothing is a 'perfect shape'. For some reason, this is. It looks like a hexagonal chunk of Saturn is missing. Clouds swirl around it at thousands of miles an hour. It is big enough to fit three Earths side by side. Some clouds can break free and be ripped apart by the wind, by entering this hole. I'm not one of those people who belive in 'flying sausers', but a hexagon? A HEXAGON? If I recall, I have never heard of a hexagon anywhere in space, just circles, disks, irregular, and spheres. Not Hexagons. :?

 

[MeteorWayne]

This was discussed here a long time ago, but unfortunately, the thread was lost during one of the SDC brain failures.

Welcome to Space.com

Wayne

 

[MetalMario]

Thanks!

 

[Shadowslayer81]

I've seen that picture and was thinking that it didn't look too much like a hexigon, more like a circle with irregularites. Must be the magnificent ability to see patterns in things that are random. Kinda like when somebody sees Jesus in a loaf of bread. Come to think of it if nasa were to "see"cough photoshop cough a deities head in the clouds of some gas giant you could probably get the religious people to bankroll a mission to do some awesome science at said gas giant. When you get there and the head isn't in the ultra high res pics you just say "Well he does work in mysterious ways"

Oh found the hexagon of saturn http://en.wikipedia.org/wiki/File:Satur ... eature.jpg

 

[nimbus]

 

[Boris_Badenov]

Here is shadowslayer's pic. IIRC, there is one at the Venusian South Pole too.

 

[silylene]

Just after the photo was published (Tue Mar 27, 2007 1:06 pm ), I actually first proposed that the hexagonal circulation pattern on Saturn's poles was an enormous example of a Benard-Marangoni convection cell.

What happened afterwards, to me, was rather fascinating. Since that post was published, this post and several subsequent posts on this subject in SDC have been re-posted on dozens of forums, often verbatim, with my name removed and someone else offering up the idea (and a non-verbatim post followed by a thread offering up this concept on UMSF). Then I saw this proposal re-posted in some online science blogs, again sometimes verbatim. Then interestingly, last year I saw a publication on this same subject in an astronomy journal, of course without my name, but with similar text and diagrams that I had in one of my subsequent posts on this subject. See for yourself, just google the phrase: saturn marangoni hexagon

http://www.space.com/common/forums/viewtopic.php?f=12&t=5173
What a beautiful example of Benard-Marangoni convection!!

Interestingly, in 1985 I published a paper on the mechanism of film striations in spin coating silicon wafers with very thin films of liquid photoresist on wafers, and showed that the film striations were formed from centrifugaly stretched Benard-Marangoni cells. In the center of a spin-coated wafer, where the stresses from wafer rotation were minimal (zero)you would always find a microscopic hexagon.

Of course the scale of what I was researching at the time was measured in micrometers, but the physics is exactly the same. It is so interesting what I observed on a micrometer scale is exactly what is obsered on a 20,000 km scale!

The Saturnian pole will have the least rotational distortion to inhibit Benard-Marangoni cell convection, and hence a hexagon is observed.

As one move away from the pole, rotational spin will drag other convection cells into bands. This is exactly what is observed. The exact same thing I observed when we spin-casted a liquid film on a wafer.

This is very exciting, and I am betting that thermally driven Marangoni-Benard cell convection on a massive scale will be the explanation of the phenomena after the research is complete.

Now I will go read the article.

I am posting a diagram I found on the web about Marangoni cell formation in crystallizing a rotating melt.

 

[nimbus]

That's nuts... And yes those pics I posted, I got from that old post of yours (or looked them up after reading your post - don't recall specifically).

 

[dragon04]

Interestingly, in 1985 I published a paper on the mechanism of film striations in spin coating silicon wafers.......

This is very exciting, and I am betting that thermally driven Marangoni-Benard cell convection on a massive scale will be the explanation of the phenomena after the research is complete.

I am posting a diagram I found on the web about Marangoni cell formation in crystallizing a rotating melt. [/i]

Methinks that jim48 isn't our only honest-to-god, bona fide trained scientist as he likes to advertise. It must have been SO cool to realize what you were seeing on Saturn via your own published work. Awesome. Just awesome.

****edited for new content*****

I had to do it. It's 80 some degrees here and I have the AC running, but I HAD to make half a pot of coffee. So I could pour Half and Half in it and watch the magic, of course. Needless to say, my wife happened into the kitchen and gave me a strange look as I stared into the Abyss that is my FOX Ohio Valley (TV Station) coffee mug.

I knew what she was thinking, but she didn't say a word. I just looked up and said... "It's Science, Honey!" After 12 years of marriage, she's used to my little idiosyncrasies, She just nodded, smiled, and went back to her computer room.

My findings, you ask? Oh.... Yes. As the convective currents brought the cream back to the top, a general swirling motion started, but more interestingly, while I didn't see anything as close to a hexagon in that Saturn image, I saw some rough approximations.

More interesting than that though was that the cream came up in, it's hard to describe. Imagine looking at, say a bundle of unsharpened pencils from the top. The cream created "cells" for the better lack of a term at the surface. It looked for all the world like close-up images of the sun's surface. Fascinating.

 

[webtaz99]

One day they'll figure this out and reproduce it in the lab. Then Sharper Image will sell a tabletop one. Like a plasma ball, but different.

 

[Bill_Wright]

I have seen polygons, including hexagons, in freezing molten metal as well as in the tundra where there is an annual freeze - thaw cycle. I have also read the paper in the 1980's referring to Marangoni-Benard cell convection, although I do not have it in front of me so I can't confirm the author. The scale I have seen this pattern is in between the micro and the macro so it doesn't surprise me that is has been observed in both. Sorry, no new news here folks.
-- Bill

 

[xXTheOneRavenXx]

When they decide to recreate your "coffee pot" experiment, I wonder if they too will use a coffee pot in the lab, lol.

 

[silylene]

I have seen polygons....Sorry, no new news here folks.
-- Bill

Wow, nothing opens your eyes?

Marangoni-Benard convection was first described in the 19th century. Of course that isn't new.

Marangoni-Benard convection in a rotating microscopic system was something I studied 24 yrs ago. Yes that was new, both in scale and that it was rotating.

What is new is that Marangoni-Benard convection appears to be observable on a planetary wide scale, and a huge gas giant at that, and on the surface of a sphere that is rotating rapidly (something new which neither Marangoni nor Benard nor others had simulated yet). And what is new is that Marangoni-Benard convection cells may be the source of the mysterious hexagon shapes in the Saturian atmosphere, and if so, that this kind of convection now has been observed on a scale as small as a few microns (films drying on a silicon wafer) to 10,000's of km (Saturn). That is a range of 1E13 in size! That isn't new either ? 13 orders of magnitude isn't even amazing and leave you surprised?

Oh by the way, hexagon formations in frozen tundra have nothing to do with Benard-Marangoni convection. It's a different mechanism.

 

[exoscientist]

Just after the photo was published (Tue Mar 27, 2007 1:06 pm ), I actually first proposed that the hexagonal circulation pattern on Saturn's poles was an enormous example of a Benard-Marangoni convection cell.
What happened afterwards, to me, was rather fascinating. Since that post was published, this post and several subsequent posts on this subject in SDC have been re-posted on dozens of forums, often verbatim, with my name removed and someone else offering up the idea (and a non-verbatim post followed by a thread offering up this concept on UMSF). Then I saw this proposal re-posted in some online science blogs, again sometimes verbatim. Then interestingly, last year I saw a publication on this same subject in an astronomy journal, of course without my name, but with similar text and diagrams that I had in one of my subsequent posts on this subject. See for yourself, just google the phrase: saturn marangoni hexagon

http://www.space.com/common/forums/viewtopic.php?f=12&t=5173
What a beautiful example of Benard-Marangoni convection!!

Interestingly, in 1985 I published a paper on the mechanism of film striations in spin coating silicon wafers with very thin films of liquid photoresist on wafers, and showed that the film striations were formed from centrifugaly stretched Benard-Marangoni cells. In the center of a spin-coated wafer, where the stresses from wafer rotation were minimal (zero)you would always find a microscopic hexagon.
Of course the scale of what I was researching at the time was measured in micrometers, but the physics is exactly the same. It is so interesting what I observed on a micrometer scale is exactly what is obsered on a 20,000 km scale!
The Saturnian pole will have the least rotational distortion to inhibit Benard-Marangoni cell convection, and hence a hexagon is observed.
As one move away from the pole, rotational spin will drag other convection cells into bands. This is exactly what is observed. The exact same thing I observed when we spin-casted a liquid film on a wafer.
This is very exciting, and I am betting that thermally driven Marangoni-Benard cell convection on a massive scale will be the explanation of the phenomena after the research is complete.
Now I will go read the article.
I am posting a diagram I found on the web about Marangoni cell formation in crystallizing a rotating melt.

Silylene, you should definitely write the journal article authors and remind them where the theory originated.
One thing, though. Doesn't Maragoni-Benard convection depend on surface tension? In that case wouldn't liquid of some form be required?

Bob Clark

 

[exoscientist]

...
Interestingly, in 1985 I published a paper on the mechanism of film striations in spin coating silicon wafers with very thin films of liquid photoresist on wafers, and showed that the film striations were formed from centrifugaly stretched Benard-Marangoni cells. In the center of a spin-coated wafer, where the stresses from wafer rotation were minimal (zero)you would always find a microscopic hexagon.
Of course the scale of what I was researching at the time was measured in micrometers, but the physics is exactly the same. It is so interesting what I observed on a micrometer scale is exactly what is obsered on a 20,000 km scale!
...

Your mentioning this reminded me of an idea I had for spin casting mirrors in space. I'll post it in another thread.


Bob Clark

 

[silylene]

Silylene, you should definitely write the journal article authors and remind them where the theory originated.
One thing, though. Doesn't Maragoni-Benard convection depend on surface tension? In that case wouldn't liquid of some form be required?

Bob Clark

Hello Bob,

I should write an article on Saturn - I would need a collaborator, planetary atmospheric physics is well enough outside my field that I don't think I could do this alone. (I did write a journal article on the microscopic convection cells.)

The circulation cells are called Benard cells, regardless of mechanism.

Benard circulation is a thermally driven circulation (also often called Rayleigh-Benard), driven by density differencs vs temperature, and gravity pulling the denser fluid downwards. This would be what is happening on Saturn.

Marangoni circulation is a surface tension driven circulation. This requires an interface between two fluids, for example at the interface between a liquid and a gas. The flow of fluid from a region of lower surface tension to higher surface tension drives this circulation (to minimization of surface energy). Often, the surface tension differences at the interface are created by temperature variations (since surface tension varies with temperature), which could be thermally driven.

I had lumped the terms together simply because I was lazy and didn't wanted to explain the difference, and some people only have heard of one term or the other.

 

[Boris_Badenov]

Just after the photo was published (Tue Mar 27, 2007 1:06 pm ), I actually first proposed that the hexagonal circulation pattern on Saturn's poles was an enormous example of a Benard-Marangoni convection cell.

What happened afterwards, to me, was rather fascinating. Since that post was published, this post and several subsequent posts on this subject in SDC have been re-posted on dozens of forums, often verbatim, with my name removed and someone else offering up the idea (and a non-verbatim post followed by a thread offering up this concept on UMSF). Then I saw this proposal re-posted in some online science blogs, again sometimes verbatim. Then interestingly, last year I saw a publication on this same subject in an astronomy journal, of course without my name, but with similar text and diagrams that I had in one of my subsequent posts on this subject. See for yourself, just google the phrase: saturn marangoni hexagon

http://www.space.com/common/forums/viewtopic.php?f=12&t=5173
What a beautiful example of Benard-Marangoni convection!!

Interestingly, in 1985 I published a paper on the mechanism of film striations in spin coating silicon wafers with very thin films of liquid photoresist on wafers, and showed that the film striations were formed from centrifugaly stretched Benard-Marangoni cells. In the center of a spin-coated wafer, where the stresses from wafer rotation were minimal (zero)you would always find a microscopic hexagon.

Of course the scale of what I was researching at the time was measured in micrometers, but the physics is exactly the same. It is so interesting what I observed on a micrometer scale is exactly what is obsered on a 20,000 km scale!

The Saturnian pole will have the least rotational distortion to inhibit Benard-Marangoni cell convection, and hence a hexagon is observed.

As one move away from the pole, rotational spin will drag other convection cells into bands. This is exactly what is observed. The exact same thing I observed when we spin-casted a liquid film on a wafer.

This is very exciting, and I am betting that thermally driven Marangoni-Benard cell convection on a massive scale will be the explanation of the phenomena after the research is complete.

Now I will go read the article.

I am posting a diagram I found on the web about Marangoni cell formation in crystallizing a rotating melt.

I remember this post quite well. :geek: I referenced it when I answered a question from a friend on how this very phenomena occurred on Saturn. I gave you credit as silylene though.

 

[yevaud]

*Bump*

Bumping this thread, for the following video: "Saturn's Strange Hexagon Simulated in Laboratory"

[youtube]http://www.youtube.com/watch?v=8eH8dJgJG-c[/youtube]

 

[silylene]

Yev, thanks! Very cool.

 

[yevaud]

I actually thought of you when I ran into it, which is why I posted it here. I recollect the discussion, in which you had some pretty direct knowledge of the effect.

Well, that and it's just plain cool...