Juno Mission, continued:

Jovian Magnetic Fields

Magnetic fields of Jupiter are asymmetrical.  The movement of compressed, metallic hydrogen within the diffuse core generates the dynamo action that creates the magnetic fields.  The magnetic fields interact with the zonal winds–jet streams that flow from east to west and west to east forming the distinct bands in the atmosphere and a gigantic storm blue spot.  The magnetic fields have secular or time-based variation changing within the five-year period of observations made during the Juno mission.

This still from an animation illustrates Jupiter’s magnetic field at a single moment in time. The Great Blue Spot, an-invisible-to-the-eye concentration of magnetic field near the equator, stands out as a particularly strong feature. Credits: NASA/JPL-Caltech/Harvard/Moore et al.

Ganymede Discoveries

Ganymede’s surface ice is 150 kilometers deep and covers an ocean. Ices on the surface have different structures and temperatures.  Ganymede is airless and is constantly bombarded by plasma from Jupiter’s magnetosphere.  The bombardment by Jupiter’s high energy particles has changed the composition of Ganymede’s ice at high latitudes.  Fine grained water ice dominates this region.  At lower latitudes, Ganymede’s magnetic fields protect the ice where it still contains the original non-water components—salts and organics.  Lines on Ganymede’s surface suggest plate tectonics.  The lighter areas are younger, the darker older.  Ganymede has a magnetic field and generates waves that have been recorded by Juno’s WAVES instrument that tracks electric and magnetic radio waves. The recording has been generated by shifting the wave frequencies into the audio range. Watch video: https://youtu.be/_09R6jIo74U

Juno’s ten-year mission ended in July 2021, but has been extended through September 2025 or until the satellite stops functioning.  It will continue to observe Jupiter and Ganymede emphasizing Jupiter’s more northward regions, faint rings and dust particles.  It will also extend its observations to Europa and Io focusing on radiation from their tori, ring-shaped clouds of ions, and volcanic activity.  The observations of the Galilean moons will provide useful information to the upcoming missions:  NASA Europa Clipper and ESA JUICE (Jupiter Icy Moon Explorer)

Raw mission data sets from the Junocam for generating images of Jupiter are available at https://www.missionjuno.swri.edu/junocam/processing#Welcome.  Join citizen scientists and artists and use the data to create new images of Jupiter and its moons.