Jupiter's magnetic field is extremely bizarre, probably due to unknown processes in his heart

The first map of the Jovian magnetic field has been compiled by an international team of researchers – and the heads are still scratched. The magnetic field of the gas giants is different from anything we have seen, referring to unknown processes that take place beneath its surface.

King of the gods

No researcher was surprised that Jupiter's magnetic field is unique. While the gas giant has 11 times the diameter of our planet, its magnetic field is 20,000 times stronger. It is also much larger and has several complex features that have no counterpart in the magnetic signature of our own planet. These characteristics, as far as we know, can come from the fast rotation of Jupiter and the large size of the liquid metallic hydrogen interior.

The new data returned by the Juno spacecraft – which is still in orbit around the poles of the planet – have allowed researchers from the United States and Denmark to study this magnetic field much more closely than ever before. From these data, retrieved from eight orbits, they mapped the magnetic field with unprecedented detail at depths of up to 10,000 kilometers (6,214 miles). Instead of making things clearer, the wealth of data only created additional confusion. Viewing:

Image credits Moore et al., 2018, Nature.

The magnetic field of Jupiter emerges from a large area near its North Pole (in red on the image above) and returns around the South Pole – so far this is not particularly surprising. What is very surprising, however, is that part of the magnetic field is entering a highly concentrated area just south of the equator – an area the team calls the Great Blue Spot.

The field is much weaker outside these areas (gray-blue in the picture above).

The Earth's magnetic field is dipolar. The field emerges from the South Pole, enters by the North Pole and crosses the center of the planet. There are small non-dipolar components, but they are relatively evenly distributed between the two hemispheres and they are not nearly as massive as the Great Blue Spot.

None of this has prepared us for the magnetic display of Jupiter.

"Before the Juno mission, our best maps of Jupiter's field looked like the Earth's field," said Harvard University global scientist Kimberly Moore. Newsweek. "The main surprise was that the field of Jupiter is so simple in one hemisphere and so complicated in the other. None of the existing models predicted a field like that. "

Image Credits

The one-sided nature of Jupiter's magnetic field indicates processes still unknown beneath the surface. Magnetic fields are the product of conducting liquid flows inside a planet. As the planet rotates, these liquids create magnetic fields, just like a dynamo.

The dynamo of the Earth is surrounded by a solid crust; The team thinks their results suggest that Jupiter's dynamo is devoid of this case. One of the models they propose envisions the Jupiter core not as a solid, but as a mud – a mixture of rock and ice partially dissolved in liquid metallic hydrogen. Such a structure could create layers that would result in an asymmetric magnetic field, they explain.

Another possibility is that the helium rains on the planet will act to destabilize the terrain. This scenario, however, fails to satisfactorily explain the asymmetry observed in the magnetic field.

Juno is still in orbit around Jupiter and will continue for a long time. The team hopes to use other observations to better understand the magnetic field it has discovered.

The study entitled "A complex dynamo deduced from the hemispherical dichotomy of the magnetic field of Jupiter" was published in the journal Nature.

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