Scientists mapped Jupiter’s crazy magnetic field

Understanding the magnetic field can help answer questions about Jupiter’s inner structure.

Image: Moore et al./Nature
Image: Moore et al./Nature

Scientists for the first time have detected Jupiter’s crazy magnetic field using NASA’s Juno spacecraft showing it is confined almost entirely to the northern hemisphere.

Jupiter has a huge magnetic field. This magnetic field is the reason for the planet’s magnetosphere and the incredible aurora that appear at the poles. Scientists believe that the understanding of this magnetic field could help them get insights into the inner structure of the Jupiter.

Juno was launched into space in 2011 and has spent the last two years orbiting the gas giant. Its primary goal is to understand the origin and evolution of Jupiter—as the biggest planet in our solar system by far, it could provide key insights into planetary systems of other stars.

In a new study by the U.S. and Denmark, scientists have created a map of Jupiter’s magnetic field, showing it in unprecedented detail. created a map of Jupiter’s magnetic field, showing it in unprecedented detail. They found that the field is non-dipole and this is almost entirely confined to the northern hemisphere.

Scientists mapped the magnetic field at a range of depths and found that most of the activity takes place from a narrow band in the northern hemisphere that re-enters the planet near the Great Blue Spot, close to the equator.

Kimberly Moore, co-author of the study said, “We were not expecting Jupiter’s field to look this way. Before the Juno mission, our best maps of Jupiter’s field resembled Earth’s field.”

“The main surprise was that Jupiter’s field is so simple in one hemisphere and so complicated in the other. None of the existing models predicted a field like that. We were also surprised to learn the Great Blue Spot is a singular feature in the field. When we first observed it on Juno’s first orbit, we thought there would be others like it, but that’s not the case.”

“While the magnetic field in each hemisphere is completely different, it is too early to say whether the hemispheres are different in other ways. The team put forward a number of scenarios that could explain the unusual magnetic field—it could be related to Jupiter’s core, which at the moment is considered either to be a solid mass or more of a liquid. There could also be stable layers of liquid inside the planet, creating regional zones where the fluid can flow.”

“A common picture of Jupiter’s interior is that there is a tiny core of solid rock and ice in the middle. However, rock and ice may dissolve in liquid metallic hydrogen at the high temperatures and pressures present at depth. So any rocky material inside Jupiter might just be mixed into the liquid hydrogen-like salt dissolved in water.”

“NASA’s John Connerney, one of the study authors, said: “We have thus far developed our new model of Jupiter’s magnetic field using only the first eight orbits from an expected total of 34 orbits; so this first glimpse is a lower resolution version of what is to come.”

The study is published their study in the journal Nature.