Some surprises about Jupiter revealed by the Juno space probe

Jupiter's South Pole (Image NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles)
Jupiter’s South Pole (Image NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles)

Two articles published in the journal “Science” and a special issue of the journal “Geophysical Research Letters” describe various researches about the planet Jupiter based on data collected by NASA’s Juno space probe. Many scientists participated in one or more of those researches, each focusing on a phenomenon in progress on Jupiter and in the area of ​​influence of its magnetic field, with several news that sometimes are surprising.

The Juno space srobe entered the planet Jupiter’s orbit on June 4, 2016 and after some time started its scientific mission. This is a mission less focused on photos than others but there are still some very interesting and looking magnificent giving a great sense-of-wonder. Instead, a variety of instruments of various kinds have the purpose of detecting various types of data on Jupiter’s atmosphere, its interior, its magnetosphere, its aurora, and more.

The JunoCam camera’s usefulness has been perhaps underestimated but several amazing pictures made the photos it took really important. It made it possible to detect the variability of Jupiter’s surface’s appearance while the Juno space probe was flying around it but above all it allowed to obtain extraordinary images of its polar areas. The surprise came from the fact that in those areas there are no bands like in the rest of the planet but there are huge cyclones that have a diameter that can reach 1,000 kilometers (about 600 miles).

Scientists have no explanation for the formation of all those cyclones and there are other questions about them. For example, it’s unclear how many cyclones are stable so one or more of them may disappear during the mission of the Juno space probe or keep on existing for a long time. The number of cyclones is different at the two poles but at the moment there’s no explanation, which may be related to the other questions.

One important measure concerned Jupiter’s magnetic field. Its remarkable intensity was already known but from the magnetometer investigation (MAG) instrument’s detection it turns out it’s even more powerful with its 7,766 Gauss, about 10 times more powerful than the most powerful magnetic field on Earth. The measurements indicate that it’s uneven and this suggests that it can be generated by a dynamo effect closer to the surface rather than just in the planet’s core.

Among the effects of Jupiter’s magnetic field there are polar auroras. The Jovian Auroral Distributions Experiment (JADE) and Ultraviolet Imaging Spectrograph (UVS) instruments were very useful to detect electrons and ions associated with the auroras and to examin them at ultraviolets. This isn’t the first study of Jupiter’s auroras but the Juno space probe is equipped with specific instruments that are providing information suggesting that the processes in progress are only partially similar to those connected to the creation of Earth’s auroras.

During its August 27, 2016 Jupiter flyby, the Juno space probe also met the planet’s bow shock, that is, the contact area between solar wind and Jupiter’s magnetosphere that constitutes a boundary between them in which the solar wind slows down abruptly. After analyzing the data, the researchers concluded that at that time Jupiter’s magnetosphere was expanding at both poles.

The detections show that Jupiter is different from what the researchers were expecting and for the moment there was an analysis of the data directly collected but for example there’s still a great work to do to interpret the data on the planet’s core. Inside Jupiter there seem to be unforeseen motions so at this point it’s possible that the core is not solid.

In essence, the first researches based on the data detected by the Juno space probe show that this mission is allowing us to get to know Jupiter much better than before. The conditions in which it’s working are really difficult because of its powerful magnetic field so the various instruments will start breaking down but in the meantime Juno will keep on collecting precious data.


Variability of Jupiter's surface (Image NASA/SWRI/MSSS/Gerald Eichstadt/Sean Doran)
Variability of Jupiter’s surface (Image NASA/SWRI/MSSS/Gerald Eichstadt/Sean Doran)

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