Saturn Hexagon
Finding polygons in space is never easy. In fact is in most cases close to impossible given current technology. For the longest time when astronomers observed space they saw a universe of circular shapes. There are the spherical shapes of planets, the circular disks of the observable sun and and moon, and the majestic spirals of galaxies. So it was a great suprise to many in the scientific community when it was found out that images taken by the Voyager craft found out that there was an unusually geometrically accurate hexagon formation of clouds at Saturn’s North pole.
The first image was taken over 26 years ago but it was also confirmed by Cassini a probe sent later on to Saturn. The images showed a well defined hexagon that does not often occur in nature at the macroscopic scale especially with weather patterns. In most ways the polar vortex is similar those found on Earth. However Earth’s polar vortexes are round. Scientists are baffled about what might be causing the unique shape.
To be fair the hexagon is not a perfect one. The sides while uncannily straight, don’t meet in perfect corners. In stead the corners of the hexagon are rounded. Showing that even this unusual vortex can’t full escape the dynamics that govern cloud patterns. The most recent images of the vortex were taken in 2007 by Cassini. The imagers show that the vortex is 25,000 km or 15,000 miles. So in short it is pretty huge but that is not the only amazing thing about the hexagon. Saturn is a gas giant so its atmosphere is incredibly thick. Infrared imaging has show that the formation is not a simple surface feature of the polar vortex. it actually extends 100km into Saturn’s atmosphere.
The Saturn Hexagon has also proven to be one of the most difficult targets in space to really investigate. One reason is that the North Pole of Saturn is exposed to sunlight only every 15 years. This makes it impossible to get accurate images without the use of radio imaging. Right now scientists have different guesses for what causes the unique shape of Saturn’s polar vortex. One hypothesis has to do with composition of the atmosphere which is radically different’ from Earth’s. Another consideration is the thickness of Saturn’s atmosphere which would set up unique conditions for fluid dynamics.
We have written many articles about Saturn for Universe Today. Here are some interesting facts about Saturn, and here are some pictures of Saturn.
If you’d like more info on Saturn, check out Hubblesite’s News Releases about Saturn. And here’s a link to the homepage of NASA’s Cassini spacecraft, which is orbiting Saturn.
We’ve also recorded an episode of Astronomy Cast all about Saturn. Listen here, Episode 59: Saturn.
Source:
NASA
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