Cassini Probes the Hexagon On Saturn

Riding with Robots sends us to a NASA page with photos of a little-understood hexagonal shape surrounding Saturn's north pole. "This is a very strange feature, lying in a precise geometric fashion with six nearly equally straight sides," said Kevin Baines, member of Cassini's visual and infrared mapping spectrometer team. "We've never seen anything like this on any other planet." This structure was discovered by the Voyager probes over 20 years ago (here's an 18-year-old note on the mystery). The fact that it's still in place means it is stable and long-lived. Scientists have no idea what causes the hexagon. It's nearly big enough to fit four earths inside — comfortably larger than Jupiter's Great Red Spot. The article has an animation of clouds moving within the hexagon captured in infrared light.

Comments

Re:/. story about spinning water?

[omnilynx]

Another related possibility is spherical harmonics, similar to what happens in the sun. The planet would be effectively resonating like a 3D drumhead. If that's true, there should be other points on the surface that exhibit similar phenomena.

Re:/. story about spinning water?

[Rei]

The curious thing, though, is that the south pole is very different -- almost looks like a human eye. I wonder what sort of rotational effect could cause such an asymmetry between north and south poles?

It's a Dissipative Structure

[vandan]

Fritjov Capra ( this guy's an absolute legend, by the way ) had an interesting section on hexagonal structures like these in his book, Web of Life. He was talking about Dissipative Structures, discovered by Ilya Prigogine.

In the experiment that was being described, a small dish of water was heated up uniformly from below. At a certain point, these hexagonal structures emerged. Hot water would rise from the bottom of the dish, travelling in a pipe directly through the middle of the hexagon ( forming a point in the middle that you could see ). When the water hit the surface, it spread out cooled, and then travelled back down to the bottom, creating the sides of the hexagon. Apparently they were getting multiple hexagons, and they were incredibly stable ... ie you could run a pen through them and disturb them, and they'd immediately revert to these perfect hexagons. It was fascinating reading - thoroughly recommended for people interested in biology, physics, and philosophy.