The armoured Juno spacecraft has transmitted science data back to NASA after flying past the planet last summer – and it’s thrown up new mysteries about the huge planet.
The Juno probe has taken five years to make the 1.4 billion mile journey to the solar system’s largest planet – and flew within 2,600 miles of the planet’s cloud tops.
We knew, going in, that Jupiter would throw us some curves,’ said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio.
‘There is so much going on here that we didn’t expect that we have had to take a step back and begin to rethink of this as a whole new Jupiter.’
Among the findings that challenge assumptions are those provided by Juno’s imager, JunoCam.
The images show both of Jupiter’s poles are covered in Earth-sized swirling storms that are densely clustered and rubbing together.
‘We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole.’ said Bolton.
Another surprise comes from Juno’s Microwave Radiometer (MWR), which samples the thermal microwave radiation from Jupiter’s atmosphere, from the top of the ammonia clouds to deep within its atmosphere.
The MWR data indicates that Jupiter’s iconic belts and zones are mysterious, with the belt near the equator penetrating all the way down, while the belts and zones at other latitudes seem to evolve to other structures.
Measurements of the massive planet’s magnetosphere, from Juno’s magnetometer investigation (MAG), indicate that Jupiter’s magnetic field is even stronger than models expected, and more irregular in shape.
‘Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,’ said Jack Connerney, Juno deputy principal investigator and the lead for the mission’s magnetic field investigation at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
‘Already we see that the magnetic field looks lumpy: it is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter’s dynamo works.’