Jupiter, the largest planet in our solar system, has dozens of polar cyclones, some up to 900 miles across, and a magnetic field 10 times stronger than Earthβs β findings that surprised scientists involved in NASAβs Juno mission.
Scientists reported initial results from the closest and deepest views of giant Jupiterβs polar regions in a NASA news conference and papers in the journal Science on Thursday.
βItβs making us rethink how giant planets work,β said Scott Bolton of Southwest Research Institute in San Antonio, principal investigator for the mission.
Bolton and mission scientists said initial science results from Juno, which has made six close passes of the planetβs poles since arriving on July 4, 2016, upset many of their notions about the planet.
Those massive storms were unexpected as was the direction of the energetic particles that cause the planetβs polar auroras.
Unlike Earth, where auroras are caused by particles coming from the sun and crashing into the Earth, Jupiterβs particle streams emanate from the planet.
Measurements of the planetβs gravity field also donβt fit models based on previous data. Scientists had expected to determine that Jupiter either had a dense, compact core or none at all, said Bolton.
βWhat we found was that really neither is true,β said Bolton. The core is larger and less dense than expected.
William Hubbard, a Juno co-investigator who created models for Junoβs core, said βthe core of heavier material is fuzzierβ than anticipated.
There is a denser region, but it appears to be diluted with hydrogen, he said.
Hubbard is professor emeritus at the University of Arizona Lunar and Planetary Laboratory.
He said the emerging picture of Jupiter will be refined as Juno continues its two-year investigation.
βItβs kind of like where you have your first pass of a picture sketched in, then you start filling in the details. We just had our sixth close pass and with each one the gravity field is getting much more precise.β
The radiation environment of Jupiter makes it necessary to stay high above its magnetic field.
Juno speeds by the poles, under those fields, in a two-hour plunge every 53 days, gathering information with an array of instruments and images with its JunoCam.
Most of the images on the NASA Juno website were created from the cameraβs data by amateur astrophotographers, said Candice Hansen of Tucson-based Planetary Science Institute.
βWe have a very tiny, tiny operations team and the contributions of the amateurs are essential,β Hansen said. βOver 900 contributions on the website were processed by the public.β