NASA's Juno probe 'hears' sounds of Jupiter's moon Ganymede

The findings come amid the most detailed ever map of Jupiter's magnetic field, which shows the drifting of the Great Red Spot and Great Blue Spot.

Jupiter, the solar system's largest planet, is seen alongside its moons (illustrative). (photo credit: PIXABAY)
Jupiter, the solar system's largest planet, is seen alongside its moons (illustrative).
(photo credit: PIXABAY)

NASA's Juno probe recorded audio in its recent flyby of Jupiter's moon, Ganymede, essentially "hearing" the moon, NASA revealed at the American Geophysical Union Fall meeting.

The Juno probe, launched in 2011, has recovered a host of valuable data about the largest planet in the solar system and its many moons. For example, the probe was able to bring back data that measured the depth of the Great Red Spot and described how storms formed inside the gas giant.

Now, NASA scientists can add hearing audio from Ganymede to that list.

The recording itself is just 50 seconds long and was generated from the data gathered on the last flyby of Ganymede on June 7, 2021, picked up by Juno's Waves instrument.

“This soundtrack is just wild enough to make you feel as if you were riding along as Juno sails past Ganymede for the first time in more than two decades,” said Juno principal investigator Scott Bolton. “If you listen closely, you can hear the abrupt change to higher frequencies around the midpoint of the recording, which represents entry into a different region in Ganymede's magnetosphere.”

The sounds of the moon may not essentially be special and do not indicate that there is something especially unique about it.

But while the sounds might not indicate this, other information does suggest otherwise.

Ganymede is the largest of Jupiter's moons and is, in fact, the largest moon in the solar system - dwarfing even the planet Mercury. The large moon has long been theorized to also host water, based on circumstantial evidence, though recent findings from data gathered from the Hubble Space Telescope did find tangible evidence of water vapor.

Ultimately, more analysis of the audio data is needed to fully understand the findings. 

But for NASA's Juno probe, the most exciting aspect of the recent briefing is not the audio data, but the precise mapping of Jupiter's magnetic field.

This map is the most detailed of the magnetic field ever made and has provided new and significant detail to our understanding of the planet. The map details the zonal winds (Jupiter's jet streams that run east to west and west to east) and has determined that the Great Red Spot is drifting around the planet.

The findings also revealed information about the equally mysterious but not as famous Great Blue Spot, a strange magnetic anomaly in the equator. This spot is moving eastward, and at a far slower pace, but is also being pulled apart by the zonal winds.

Understanding Jupiter's atmosphere holds major implications for Earth, as well, as the magnetic field map of Jupiter allows scientists to make significant comparisons with that of our own.

Earth, like Jupiter, also is influenced by jet streams. But Earth only has one, flowing east to west. Earth also has two Ferrel cells, part of the planetary air circulation which is balanced with the jet stream. This is integral for the maintenance and functionality of a planet’s environment and climate.

Jupiter also has Ferrel cells, but rather than being just two, there are 16. 

In a way, this makes Jupiter similar to Earth, as the jet streams and Ferrel cells affect Jupiter’s circulation system in a similar way as Earth’s.

This could also happen on other planets, though it isn't as clear. This is especially the case with Saturn, which is known to have jet streams and storms, but not as much information is known about the ringed planet at this time.

It is possible that more information will be gained in the future, with more missions planned to be launched towards Jupiter. NASA recently launched the Lucy mission to study Jupiter's Trojan asteroids, two large clusters of space rocks that scientists believe are remnants of the primordial material that formed the solar system's outer planets.

The European Space Agency (ESA) is also planning on launching the Jupiter ICy moons Explorer (JUICE) mission in 2022, which will arrive in 2029 and observe the planet and the three largest Jovian moons, including Ganymede.

NASA also has plans for the Jovian moons, with a probe dubbed the Europa Clipper set to be launched to the eponymous moon in 2024 and arrive in 2030, to see if the moon can support life.