September 06, 2016
from SpaceWeather Website



On August 27, for the first time ever, NASA's Juno spacecraft swooped over Jupiter's south pole.


The flyby revealed an astonishing vortex of infra-red light:



"While we knew that the flyby of Jupiter's south pole might reveal the planet's southern aurora, we were still amazed to see it for the first time," says Alberto Adriani from the Istituto di Astrofisica e Planetologia Spaziali in Rome.

Alberto Adriani is a co-investigator on the Jovian Infrared Auroral Mapper (JIRAM), the instrument that took the picture.

Another instrument on Juno named "Waves" detected low-frequency (<100 kHz) radio signals coming from Jupiter's aurora-zone. To make these signals audible, mission scientists at the University of Iowa shifted the signals into the frequency range of human hearing.


The audio begins about 30 seconds into this movie:



Thirteen hours of radio emissions from Jupiter's intense auroras are presented here, both visually and in sound.


The data was collected when the spacecraft made its first orbital pass of the gas giant on Aug 27, 2016, with all spacecraft instruments turned on.


The frequency range of these signals is from 7 to 140 kilohertz. Radio astronomers call these "kilometric emissions" because their wavelengths are about a kilometer long.



If the auroras of Jupiter sound mysterious - that's because they are.

Unlike Earth, which lights up in response to solar activity, Jupiter makes its own auroras. The power source is the giant planet's own rotation. Although Jupiter is ten times wider than Earth, it manages to spin around 2.5 times as fast as our little planet.


As any freshman engineering student knows, if you spin a magnet you've got an electric generator. And Jupiter is a very big magnet. Induced electric fields accelerate particles toward Jupiter's poles where the aurora action takes place.


Remarkably, many of the particles that rain down on Jupiter's poles appear to be ejecta from volcanoes on Io. How this complicated system actually works is a puzzle.