content long 22-October-2017 14:02:21

Winners Italy

16-18 years old: The hexagon at Saturn's north pole

 Author: Emanuele Nasini

This year the Cassini’s contest has submitted three very interesting targets: if choosing the first one we can study the features of the underground ocean of Enceladus in search of life, while if we choose the second one we are able to study Titan in depth, particularly its mysterious atmosphere.

However, despite these opponents, I have decided to dedicate my full attention to the third target, hoping to succeed in getting the instruments of the Cassini probe to focus on the huge Saturn’s Hexagon. Apparently this study might appear superfluous, nearly wasteful, but from the observation of phenomena that seem far away from our “terrestrial” reality you can get amazing results. The unconventional shape consists of a weird hexagonal clouds pattern around Saturn’s north pole discovered by the Voyager spacecraft in the early 1980s and recently ‘captured’ by Cassini’s cameras. This honeycombed-shaped structure encircles Saturn with an estimated diameter wider than two Earths and encloses an intensive hurricane which has been raging for decades (maybe centuries) and it doesn’t seem to decrease power. Several laboratory experiments have been performed to try to understand the reason of that geometrical shape and the same conclusion has been reached, namely that this bizarre structure is due to the different velocity gradients in the different parts of the vortex: in fact the central part of the Saturn cyclone spins much faster than its external clouds. However it cannot be regarded as a certain and definitive explanation without knowing all the data related to the phenomenon: the south pole of Saturn also presents a storm, but it has a circular shape and so it can be assumed that on the two pole there are factors acting differently.

To obtain the missing information fortunately we can appeal to our dear probe Cassini, which is coming to the final part of its mission: it is currently in the phase known as “Ring-Grazing orbits” in which it’s making twenty pretty reckless orbits through the gas giant’s rings. Since these “flights” are almost parallel to the axis of Saturn and grazing the planet itself, it may be an excellent occasion to obtain data and photos of the two poles, in particular the northern one that in this period is illuminated by sunlight.

Thanks to these information it will be possible to study in detail all the aspects and causes of the “mysterious” hexagon gaining models that will broaden our view of the general fluid dynamics, to be afterwards applied to the study of the poles of Solar System planets that have a very “turbulent” atmosphere, such as Jupiter or Venus; or even more important for a detailed study of our atmosphere: in particular to try to understand how it will evolve in the future and determine which is our actual impact on it, in order to search for solutions and improve our techniques to preserve it.

In short, since the Cassini mission will end this year we can’t miss this wonderful opportunity!


Last Update: 19 May 2017

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