The radio emissions cast by Jupiter’s auroras — light shows similar to the northern and southern lights on Earth — were recorded by an instrument, called Waves, as the Juno spacecraft traveled about 4,100 km above Jupiter’s swirling clouds.
Those emission recordings were then converted into sound files by researchers at University of Iowa.
The emissions from Jupiter were discovered in the 1950s but had never been analysed from such a close vantage point, according to NASA.
“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, research scientist at the UI. “Waves detected the signature emissions of the energetic particles that generate the massive auroras that encircle Jupiter’s north pole,” said Kurth.
“These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons that are generating them come from,” he said.
The scientists want to learn how electrons and ions are accelerated along magnetic field lines above Jupiter to eventually collide with the atmosphere, creating the bursts of light that become the auroras.
Kurth likened plasma to a stringed instrument.
“If you pluck a string on a violin, the string vibrates. The vibrating string is like the plasma itself; in the plasma it is the charged particles that are moving,” he said.
Yet those radio waves can not be heard. Instead, they need to be “downshifted” to the audio range and then compressed to turn multiple hours of measurements into an abbreviated soundtrack, Kurth said.
A camera aboard the spacecraft captured high-resolution views of the Jovian atmosphere and the first glimpse of Jupiter’s north and south poles.
The August 27 flyby was the closest the Juno spacecraft will get to Jupiter. Thirty-five more close flybys are planned during Juno’s mission, which is scheduled to end in February 2018.