What we know about Jupiter’s Great Red Spot

It is the largest storm in the Solar System, but its depth is only between 300 and 500 kilometers. The measurements were made by Nasa's Juno probe.

There is a Great Red Spot on Jupiter that represents the largest storm in the Solar System, with an extent of 16,000 kilometers. But its depth is much shallower and is between 300 and 500 kilometers, much less than the 3,000 kilometers to which the zonal winds that create the bands on the large gaseous planet reach. The new readings were made by Nasa's Juno probe, which measured gravity thanks to the KaT, Ka-Band Translator instrument, made by Thales Alenia Space Italia with the support of the Italian Space Agency (ASI).

The study of Jupiter's Great Red Spot

The analysis of Jupiter's Great Red Spot was coordinated by Marzia Parisi, a former doctoral student at Sapienza University and now at NASA's Jet Propulsion Laboratory (JPL), together with an international group including Daniele Durante and Luciano Iess, from the Department of Mechanical and Aerospace Engineering at Sapienza University in Rome. The research was published in the journal Science. Because Jupiter's interior is not directly observable, accurate measurements of the gravitational field were used to understand its structure.

What the data say about Jupiter's Great Red Spot

Juno collected data during two close flyovers in February and July 2019. Daniele Durante explained that the measurements "attest to a storm mass equal to about half of Earth's entire atmosphere and slightly less than that of all the water in the Mediterranean Sea." The Great Red Spot would thus be an object quite similar to a very large disk, the smaller size of which is equal to the diameter of the Earth. At the same time, the depth is quite thin. Overall, Jupiter's "spot" would have characteristics reminiscent of those of Earth's largest storms.

Luciano Iess pointed out that Juno's measurements "Have provided  the third dimension to that phenomenon in Jupiter's atmosphere that has attracted the attention of many of us, as well as that of astronomers for more than 300 years, showing it to be a surface storm that is certainly very large, but very shallow. This new measurement will help understand its nature, evolution and, perhaps, its possible disappearance."

The observations of the giant gas planet are numerous and, for example, one study focused on Jupiter's strange rain that would explain the birth of Earth. Another research has identified instead a distant Jupiter-like planet that could show the future of the solar system.

Stefania Bernardini