The Nasa Juno probe, in orbit around Jupiter, was able to measure the depth of penetration of the winds under the thick blanket of clouds on the planet; it is about 3 thousand Km below the level of clouds. The discovery, to which Italy has also contributed through the La Sapienza University of Rome, will allow us to shed light on the atmospheric circulation and on the internal structure of the gas giant. The results of the research, coordinated for the Roman university by Luciano Iess, have been published in the prestigious journal Nature.
The research group with the collaboration of Daniele Durante and Paolo Racioppa and other researchers from Italian and foreign universities and scientific institutions, managed to establish the depth of the winds, based on the measurements of the planet’s gravity carried out by the probe.
The measurements of Juno were made possible by the very high precision instrument KaT, Ka-band Translator, realized by Thales Alenia Space Italy with the contribution of Sapienza researchers and financed by the Italian Space Agency (ASI).
Jupiter is a gas giant with a radius of about 70,000 km (11 times that of the Earth) and a composition very similar to that of the Sun, largely hydrogen and helium. The planet is therefore devoid of a solid surface and probably a well-defined nucleus.
The winds of the planet are determined by the same laws that regulate the atmospheric circulation on the Earth where the high and low pressure zones, associated with different densities of the atmosphere, force the movement of large air masses: the deeper the winds, the greater the atmospheric masses put into motion and the greater the variation of gravity generated. It was precisely the gravity variations associated with different atmospheric densities and wind speeds in the two hemispheres (north and south) that provide the key to exploring the depths of the planet.