NASA’s Juno spacecraft “hears” Jupiter’s moon Ganymede – Hear the dramatic flyby of the Frozen Orb


This JunoCam image shows two of Jupiter’s large rotating storms, captured during Juno’s 38th Perijove Pass, November 29, 2021. Credit: NASA / JPL-Caltech / SwRI / MSSS Image processing: Kevin M. Gill CC BY

An audio track collected during Jupiter Ganymede’s flight over the mission offers a spectacular ride. This is one of the highlights from the mission scientists shared during a briefing at the American Geophysical Union’s fall meeting.

The sounds of a Ganymede flyby, magnetic fields, and remarkable comparisons between Jupiter and Earth’s oceans and atmospheres were discussed in a briefing today on ">Nasaof the Juno mission to Jupiter at the fall meeting of the American Geophysical Union in New Orleans.

Juno principal investigator Scott Bolton of the Southwest Research Institute in San Antonio played a 50-second audio track generated from data collected during the close flyby of the Jovian moon mission Ganymede on June 7, 2021. The Juno’s Waves instrument, which plugs into electricity and magnetic radio waves produced in Jupiter’s magnetosphere, collected data on these emissions. Their frequency was then moved into the audio range to create the audio track.

“This soundtrack is just wild enough to make you feel like you’re riding as Juno walks past Ganymede for the first time in over two decades,” Bolton said. “If you listen closely, you can hear the sudden change to higher frequencies around the middle of the recording, which represents entering a different region of Ganymede’s magnetosphere.”

Radio broadcasts collected during Juno’s June 7, 2021 flyby over Jupiter Ganymede’s moon are presented here, both visually and acoustically. Credit: NASA /JPL-Caltech / SwRI / Univ of Iowa
Detailed analysis and modeling of the Waves data is underway. “It is possible that the change in frequency shortly after the closest approach was due to the shift from the night side to the day side of Ganymede,” said William Kurth of the University of Iowa in Iowa City, co-principal investigator of the Waves investigation.

At the time of Juno’s closest approach to Ganymede – on the 34th mission trip around Jupiter – the spacecraft was within 645 miles (1,038 kilometers) of the moon’s surface and was moving at a relative speed of 41,600 mph (67,000 km / h).

Magnetic Jupiter

Jack Connerney of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is the lead investigator with the Juno magnetometer and is the deputy lead investigator for the mission. His team produced the most detailed map of Jupiter’s magnetic field ever.

Compiled from data collected from 32 orbits during Juno’s main mission, the map provides new information about the gas giant’s mysterious Great Blue Spot, a magnetic anomaly at the planet’s equator. Juno data indicates that a change in the gas giant’s magnetic field has occurred during the spacecraft’s five-year orbit, and that the Great Blue Spot is drifting east at a speed of about 2 inches (4 centimeters) per second compared to the rest of Jupiter. interior, circling the planet in about 350 years.

Imager Ganymède JunoCam June 2021

This image of the Jovian moon Ganymede was obtained by the JunoCam imager aboard NASA’s Juno spacecraft as it flew over the frozen moon on June 7, 2021. Credit: NASA / JPL-Caltech / SwRI / MSSS

In contrast, the Great Red Spot – the long-lived atmospheric high just south of Jupiter’s equator – is drifting west at a relatively rapid rate, circling the planet in about four and a half years. .

Additionally, the new map shows that Jupiter’s zonal winds (jets that run east to west and west to east, giving Jupiter its distinct striped appearance) separate the Great Blue Spot. This means that the zonal winds measured at the surface of the planet reach deep inside the planet.

The new magnetic field map also allows scientists at Juno to make comparisons with the Earth’s magnetic field. The data suggests to the team that the action of the dynamo – the mechanism by which a celestial body generates a magnetic field – inside Jupiter occurs in metallic hydrogen, under a layer expressing “rain of” helium ”.

The data that Juno collects during its extended mission could further elucidate the mysteries of the dynamo effect not only on Jupiter but also on those of other planets, including the Earth.

Earth’s oceans, Jupiter’s atmosphere

Lia Siegelman, a physical oceanographer and postdoctoral fellow at the Scripps Institution of Oceanography at the University of California at San Diego, decided to study the dynamics of Jupiter’s atmosphere after noticing that cyclones at Jupiter’s pole appear to share similarities to the oceanic eddies that she studied during her time as a doctoral student.

“When I saw the richness of the turbulence around the Jovian cyclones, with all the filaments and the little eddies, it reminded me of the turbulence you see in the ocean around the eddies,” Siegelman said. “These are particularly evident in high-resolution satellite images of eddies in Earth’s oceans that are revealed by plankton blooms that act as flow tracers. “

The simplified model of Jupiter’s pole shows that geometric patterns of vortices, like those seen on Jupiter, spontaneously emerge and survive forever. This means that the basic geometric configuration of the planet allows these intriguing structures to form.

Although Jupiter’s energy system is on a much larger scale than Earth’s, understanding the dynamics of the Jovian atmosphere could help us understand the physical mechanisms at play on our own planet.

Arming Perseus

The Juno team also released their latest image of Jupiter’s weak dust ring, taken from inside the ring as viewed through the navigation camera of the spacecraft’s Stellar Reference Unit. The brightest scene of the thin stripes and neighboring dark regions of the image is related to the dust generated by two of Jupiter’s small moons, Metis and Adrastea. The image also captures the arm of the constellation Perseus.

“It is breathtaking that we can contemplate these familiar constellations from a spacecraft half a billion kilometers away,” said Heidi Becker, co-principal investigator of the Stellar Reference Unit instrument. de Juno at NASA’s Jet Propulsion Laboratory in Pasadena. “But it all looks pretty much the same as when we enjoy them from our backyards here on Earth. It’s an impressive reminder of how small we are and how much there is left for us to explore.

Juno wave sensor above Jupiter's North Pole

This artist’s rendering shows Juno above Jupiter’s north pole, with the aurora shining bright. Jupiter’s magnetic field surrounds the planet. An aurora radio wave is shown passing the spacecraft, where it is intercepted by the Waves Investigation, whose sensors are highlighted in bright green. Credit: NASA

Juno waves

The Waves instrument measures the radio and plasma waves in Jupiter’s magnetosphere, helping us understand the interactions between the planet’s magnetic field, atmosphere and magnetosphere. Waves also pays special attention to the activity associated with auroras.

Jupiter’s magnetosphere, a huge bubble created by the planet’s magnetic field, traps plasma, an electrically charged gas. The activity within this plasma, which fills the magnetosphere, triggers waves that only an instrument like Waves can detect.

Because plasma conducts electricity, it behaves like a giant circuit, connecting one region to another. Activity at one end of the magnetosphere can therefore be felt elsewhere, allowing Juno to monitor processes occurring throughout this giant region of space around Jupiter. Radio and plasma waves travel in space around all of the giant and outer planets, and previous missions have been equipped with similar instruments.

Juno’s Waves instrument consists of two sensors; one detects the electrical component of radio and plasma waves, while the other is sensitive only to the magnetic component of plasma waves. The first sensor, called an electric dipole antenna, is a V-shaped antenna, four meters across, similar to the rabbit-ear antennas that were once common on televisions. The magnetic antenna – called a magnetic search coil – consists of a coil of fine wire wound 10,000 times around a core 6 inches long (15 centimeters). The search coil measures magnetic fluctuations in the audio frequency range.

Learn more about the mission

JPL, a division of Caltech in Pasadena, Calif., Manages the Juno mission for Principal Investigator Scott J. Bolton of the Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Ala., For leading the agency’s science mission to Washington. Lockheed Martin Space in Denver built and operates the spacecraft.


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