Scientists have mapped the magnetic field of Jupiter, and nothing has ever been seen

The first map of Jupiter's magnetic field at different depths is present, and it reinforces something we already knew: it's really, really, really strange. Apart from that, however, it's different from anything planetary scientists have ever seen.

We already knew that the outer magnetic field of the gas giant was strange. For starters, it's incredibly loud. The diameter of Jupiter is more than 11 times greater than that of the Earth, but its magnetic field is 20 000 times more powerful.

It's also absolutely huge and of unparalleled complexity – the Earth's magnetic field is strong, but some of the structures observed at Jupiter's have no terrestrial equivalent. It is thought that this complexity may have something to do with the rapid rotation of Jupiter and the large interior of liquid metallic hydrogen.

But now, Juno, orbiting the poles of Jupiter, allows unprecedented access to the dynamics of this strange magnetic field, taking observations much closer than ever.

Scientists from the United States and Denmark used data from eight Juno orbits to map the magnetic field with unprecedented detail at depths of 10,000 kilometers (6,214 miles) and found that was a lot stranger than expected.

The Earth's magnetic field is mainly dipolar, as if a bar magnet was crossing the center of the planet, with the poles of the magnet at the poles of the planet, emerging from the south pole and returning to the north. There are also non-dipolar components, uniformly distributed in the hemispheres.

If you could see it, it would look a bit like this.

(Geek3 / Wikimedia Commons)

But that's not how Jupiter came out.

Instead, the field emerges from a large part of the northern hemisphere, returning around the South Pole – and from a highly concentrated region just south of the equator, which that researchers call the Great Blue Spot. Elsewhere, the field is much weaker.

Look at yourself:

(Moore et al. / Nature)"Before the Juno mission, our best maps of Jupiter's field looked like the Earth's field," Harvard University global scientist Kimberly Moore told 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.

In another strange finding, the researchers found that the non-dipole portion of the magnetic field is almost entirely concentrated in the northern hemisphere. Everything is deeply unbalanced and totally unique.

This indicates that something unfamiliar is happening inside Jupiter.

Magnetic fields are generated by conducting liquids inside a planet. Combined with the rotation of the planet, they generate magnetism. This is called a planetary dynamo. In the Earth, the dynamo operates in a thick and uniform shell.

The researchers believe that their discovery indicates that this is not the case with Jupiter. One of the models, they proposed, is that the Jupiter core is not a solid, tiny rock and ice ball, but a sheet of rock fragments and partially dissolved ice in metallic hydrogen liquid.

This could create layers whose dynamics generate an asymmetric magnetic field.

Another explanation could be helium rain, which could destabilize the terrain, although, according to the researchers, it is unlikely to take into account hemispheric asymmetry.

In total, Juno is expected to make 34 Jupiter orbits. The team plans to use future observations to try to solve the mystery.

Their research was published in the journal Nature.