The Intense Invisible Aurora

Jupiter has aurora.  It’s not surprising since it has a very powerful magnetic field.  It’s only natural that the two largest structures in the solar system, the Sun’s solar wind influence (called the heliosphere)  and Jupiter’s magnetosphere, should be constantly battling. But don’t expect to see Jupiter’s aurora through a backyard telescope.  The result of this battle is far more energetic, producing an aurora invisible to the human eye, one made of X-rays.

Artistic rendering of Jupiter’s magnetosphere. Credit: JAXA

The Sun constantly blasts charged particles off into space in all directions, assaulting the planets, moons, and other solar system bodies.  It is this blast of solar wind that gives rise to aurorae here on Earth. Occasionally the solar wind is exceptionally strong, causing huge disruptions, such as power outages or aurorae that reach further from the poles.  For Jupiter, with it’s massive magnetosphere, a strong burst of solar wind shifts its magnetic boundary by as much as 2 million kilometers.

It’s this interaction at the boundary that gives rise to the X-ray aurora around Jupiter’s poles that are larger than the entire Earth.  This is the first time astronomers have studied the behavior of these massive aurora during peak solar activity. Studies of the magnetic field of Jupiter and its interaction with the solar wind come as the Juno spacecraft nears it’s rendezvous with the gas giant this Summer.  Launched by NASA in 2011, Juno aims to unlock the secrets of Jupiter’s formation in order to understand the formation of the solar system.  Part of the mission is to study the origins of Jupiter’s aurorae and the behavior of its magnetic field.

Studying the changes in Jupiter’s aurora as it interacts with the solar wind gives insights into magnetism across the galaxy.  Most stars have magnetic fields, and there are still millions of other magnetic objects in the sky, such as brown dwarfs and neutron stars.  And understanding what happens close to home will reveal the secrets of the universe.


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