A journal published in Nature reveals that Saturns famous hexagonal storm front extends far beyond cloud level in to the planets stratosphere during the summer time, indicating that it is some sort of atmospheric vortex.
In 2004 the Cassini probe measured a warm high altitude vortex over top of Saturns south pole. Scientists are beginning to decrypt even more data from the now demised cassini probe suggesting that a similiar vortex exists over top of the north pole, where Saturns famous hexagonal storm spirals around indefinitely.
The newly discovered northern vortex extends straight up in to the stratosphere and only forms in the summer, which lasts about 7 years on Saturn. Furthermore it turns out to be the exact same shape as the hexagonal cloud formation lower in the atmosphere.
“The edges of this newly-found vortex appear to be hexagonal, precisely matching a famous and bizarre hexagonal cloud pattern we see deeper down in Saturn’s atmosphere,” said planetary scientist Leigh Fletcher of the University of Leicester in the UK.
“While we did expect to see a vortex of some kind at Saturn’s north pole as it grew warmer, its shape is really surprising. Either a hexagon has spawned spontaneously and identically at two different altitudes, one lower in the clouds and one high in the stratosphere, or the hexagon is in fact a towering structure spanning a vertical range of several hundred kilometres.”
Scientists hypothesize that the original hexagonal storm was formed by a permanent jet stream flowing at around 500 kilometres per hour – roughly the same rate as which Saturn rotates. The massive formation is more then twice the size of Earth.
Saturn only began to emerge from it’s 7 year long winter in 2009
“We were able to use the CIRS instrument to explore the northern stratosphere for the first time, from 2014 onwards,” said planetary scientist Sandrine Guerlet of the Laboratoire de Météorologie Dynamique in France.
“As the polar vortex became more and more visible, we noticed it had hexagonal edges, and realised that we were seeing the pre-existing hexagon at much higher altitudes than previously thought.”
Saturns northern vortex is colder and younger than its southern vortex and unlike the southern vortex, it towers hundreds of kilometres above cloud level. What baffles scientists the most about this new discovery is how the upper stratospheric section of the northern vortex could possibly conserve a near perfect hexagonal shape. Since wind is supposed to behave differently at a higher altitude you’d think that the peculiar symmetry would begin to dissolve.
“One way that wave ‘information’ can leak upwards is via a process called evanescence, where the strength of a wave decays with height but is just about strong enough to still persist up into the stratosphere,” said Fletcher.
“We simply need to know more. It’s quite frustrating that we only discovered this stratospheric hexagon right at the end of Cassini’s lifespan.”