(ORDO NEWS) — From a distance, Saturn looks like a calm gas giant with stunning rings. However, if you fly as close as the Cassini probe, you can see much more.
An incredible hexagon-shaped storm rages around Saturn’s north pole for four decades – astronomers first discovered it in 1981 during a Voyager mission. However, even with a view from the Cassini probe, the details on Saturn’s hexagon were scarce.
A new atmospheric model tested in the laboratory suggests that the storm descends very deep, potentially thousands of kilometers away. This discovery may help explain why the storm has remained relatively stable since the first time we saw it.
In the past, observations and laboratory experiments gave two main hypotheses about how a hexagonal storm arose on Saturn.
On the one hand, it could have formed from small, alternating jets in the atmosphere of a gas giant hundreds of kilometers deep, where the pressure is about 10 bar or so, and where the gas is more turbulent.
On the other hand, a storm could arise from deep zonal jets extending thousands of kilometers down, where the pressure is tens of thousands of times greater.
In fact, shortly before Cassini finally ceased to give signals, scientists discovered that the zonal jets of Saturn persist right up to heights where the pressure is an amazing 100,000 bar or more.
Mimicking what happens with deep turbulent convection in a rotating spherical shell, researchers at Harvard University believe they have a plausible explanation of why there is a Saturn hexagon.
The three-dimensional model shows that deep thermal convection in the outer layers of gas giants can spontaneously lead to the appearance of giant polar cyclones, strong alternating zonal flows and a high-energy eastward jet model.
Moreover, these zonal jets are both qualitatively and quantitatively similar to what was observed on Saturn.
“Analysis of the simulation shows that self-organized turbulence in the form of giant vortices compresses the eastern stream, forming polygonal shapes,” the authors explain.
“We affirm that such a mechanism is responsible for the excitation of the hexagonal structure of the Saturn stream.”
But this is only a confirmation of the concept, and we will need to include much more atmospheric data from Saturn, so that the model better reflects reality. However, it seems that we are on the right track.
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