Scientists had been puzzled by a series of “hotspots” detected on Saturn’s polar regions for more than a decade. About seven years ago, NASA’s Cassini orbiter sent back to Earth more detailed imagery that had shown the spots were nothing more than gigantic polar cyclones, some of which even reaching Earth’s size.
According to older Cassini data, those cyclones’ intensity can reach speeds of 300 mph and can swirl around years on end. But scientists remained baffled by the swirling twisters’ origins.
We know that on Earth cyclones emerge and build up strength on the oceans’ heat and moisture mechanisms. But Saturn lacks any large body of water, so what may be triggering such powerful hurricane-like phenomena remained a mystery. Until now.
Cassini spacecraft’s latest data helped scientists get a grasp of the mechanism behind Saturn’s mysterious polar cyclones. MIT scientists speculate that short-termed, smaller thunderstorms in the planet’s atmosphere may have built an “angular momentum,” or a spin, which resulted in long-lasting cyclones at the poles.
In order to test their idea, MIT researchers designed a computerized model that provided them with a simulation of what may have happened in the planet’s atmosphere over the course of ages.
Scientists learned that each thunderstorm builds additional pressure at the poles by pulling air into that direction. As a result, numerous thunderstorms can build up enough atmospheric energy in the region to create a gigantic and longer-lived twister.
The planetary model also revealed that there are two factors that can influence the magnitude of a polar cyclone – the size of each individual thunderstorm as compared to the planet‘s size, and the amount of the atmospheric energy those thunderstorms can produce.
Taking into account those factors, MIT researchers were able to make predictions about two other gas giants in our solar system, Neptune and Jupiter. The team believes that Neptune has powerful cyclones at its poles but they are short-lived, while Jupiter should not have any.
Morgan O’Neill, the team’s lead researchers and former PhD student at the institute, suggested that the model could be used in studying atmospheric phenomena on planets located outside our solar system, the so-called exo-planets.
Dr. O’Neill explained that it is enough to have a picture of a “hotspot” on an exo-planet to be able to calculate storm intensity and other atmospheric conditions on that planet by just using the model.
“Before it was observed, we never considered the possibility of a cyclone on a pole,”
O’Neil said and thanked Cassini’s team for the “huge wealth of observations” the spacecraft had provided scientists with.
Image Source: Green Fudge