APOD: Saturns Hexagon Comes to Light (2012 Jan 22)

[Axel]

This is not a new pneomenon. It was studied - at least theoretically - by Kelvin in the 19th century and has been observed in laboratories, in Earth's weather, and in other contexts. See:
http://chaos.aip.org/resource/1/chaoeh/ ... horized=no
http://journals.ametsoc.org/doi/abs/10. ... 2.0.CO%3B2
http://dcwww.camd.dtu.dk/~tbohr/RotatingPolygon/
http://cjournal.concordia.ca/journalarc ... 8625.shtml

[manmeetvirdi]

Lets drop a H-Bomb right at the center and explode it!
What will happen?

[pietbeentjes]

I've made in my garden several 'squares' of round, circular tiles, starting with one in the middle, next making a round of 6 tiles fitted around that middle one, then a round of 12 tiles fitting around the former 6, then 18, 24 etc. My largest square has, in that way, 127, round tiles. In the end it comes out that every round fits within a hexagonal.

I think this could be a fair explanation for Saturn's hexagonal where a lot of clouds ("tiles") seem to be of the same dimension. The rotation of Saturn fixes them nicely in the hexagonal pattern.
I am a pensioned mathematician, so I leave the the proof of this to my younger collegues in physics, mathematics and weather dynamics.

[bystander]

APOD: Saturns Hexagon Comes to Light (2009 Dec 14)
http://asterisk.apod.com/viewtopic.php?f=9&t=17846

APOD: Unusual Auroras Over Saturn's North Pole (2008 Nov 19)
http://asterisk.apod.com/viewtopic.php?f=9&t=15074

Is the black area a circular frame or space?

The pole center was not well imaged and has been excluded.

Imaging team scientists calibrated and stitched together 55 images to create a mosaic and three-frame movie. The mosaics do not show the region directly around the north pole because it had not yet fully emerged from winter night at that time.

[eltodesukane]

The hexagon is a popular shape in nature ... witness the benzene ring and the compartments in a honeycomb.

It's kind of the best way to make a circle out of straight segments, without turning too much or too often.

[TNT]

Thanks for the clarification, bystander. I didn't understand that sentence.

[mararcin]

Isn't it obvious? We've never found Santa's home on the North Pole because he lives on Saturn's pole.

[Star*Hopper]

Technical note: two frames is not a time lapse movie.

...

Uhh....technically, it is.

[jgalt]

The hexagonal pattern is caused by a diocotron instability. The magnetic field converges at the poles causing electric current filaments (plasma) to rotate around each other. The distortions occur when two sheets of plasma flow past each other causing them to rotate in pairs and form vortices due to long range attractive electromagnetic forces and short-range repulsive forces.

[Chris Peterson]

The hexagonal pattern is caused by a diocotron instability. The magnetic field converges at the poles causing electric current filaments (plasma) to rotate around each other. The distortions occur when two sheets of plasma flow past each other causing them to rotate in pairs and form vortices due to long range attractive electromagnetic forces and short-range repulsive forces.

This is the least likely of explanations. The structure is in dense material, and is almost certainly caused by fluid dynamic effects (which is supported by the artificial creation of similar structures in the laboratory, even in the absence of a good understanding of what is going on).

Any plasma present above the atmosphere is far too tenuous, and involves far too little energy to have much impact on the dense atmosphere below. Auroras do not influence the bulk movement of Earth's atmosphere, and neither do they on other planets.

[ColoradoSky]

Anybody know: when will Cassini try again to image the north pole of Saturn?

[Strings]

I mix hexagonal suger crystals in a cup with hot water. Spin the cup and the remaining crystals in the bottom of the cup form a hexagon. Maybe hexagonal crystals in the atmosphere?