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Juno shows Jupiter's magnetic field

A team of researchers has found that Jupiter's magnetic field is quite different from Earth's

A team of researchers affiliated with several institutions in the U.S., including NASA and a pair from Denmark has found that Jupiter's magnetic field is quite different from Earth's. In their paper published in the journal Nature, the group describes their study of the planet using data from the Juno spacecraft, and what they found. Chris Jones, with the University of Leeds, offers a News and Views piece on the work done by the team in the same journal issue.


NASA launched Juno into space back in 2011, and it entered a close orbit around Jupiter in 2016—just 4,000 kilometers above its surface. Over the past two years, it has been monitoring the planet's magnetic field. In this new effort, the researchers reveal what the data shows. When mapping a planet's magnetic field, it is common to use colored lines to show magnetic flux—doing so depicts the Earth's magnetic field as lines emanating outward from the north pole then circling back at the south pole. The result resembles a giant bar magnet. But the researchers report that things are different with Jupiter. While it does have flux lines emanating from its north pole, it also has two return points, rather than just one—one is located near its south pole, the other close to its equator. Also, on Earth, parts of the magnetic field do not favor either pole, and are instead spread between the two. With Jupiter, the same kinds of magnetic fields are almost all in the northern hemisphere.


There is also the matter of how the magnetic fields are generated. Earth's magnetic field is believed to be generated by its internal dynamo—the churning of electrically conductive fluids in the core. But Jupiter is thought to be made of helium and hydrogen, which are not very conductive. This has led to theories that suggest the great pressure exerted inside the planet resulted in the formation of liquid metallic hydrogen, which, as its name implies, conducts much like a metal. The researchers note that thus far, there is no data that can explain Jupiter's odd magnetic field, but suggest it most likely has something to do with the planet's unique internal structure.


Italian participation  on the mission is based on its now established experience in the field of spectrometry, optical cameras and radio science.  In particular, Italy will supply two instruments: the infrared image spectrometer JIRAM (Jovian InfraRed Auroral Mapper, PI Angioletta Coradini INAF-IFSI, realized by Selex-Galileo Avionica) and the radio science instrument KaT (Ka-Band Translator, PI Luciano Iess of the Università 'La Sapienza' of Rome, realized by Thales Alenia Space-I) which makes up the Ka band portion of the gravity experiment.