NASA’s Juno spacecraft has just left the realm of the solar wind and entered the domain of Jupiter’s magnetosphere, within which all particles are manipulated by the planet’s immense magnetic field. When in the solar wind, Juno encountered around 16 particles per cubic inch. In the spacecraft’s current location within Jupiter’s magnetosphere, it encounters about a hundred times less. The sound in the video is the audio depiction of electromagnetic waves in the low-density space just within the magnetosphere.
Simply put, the stronger the magnetic field, the bigger the magnetosphere. Jupiter’s magnetic field is some 20,000 times more powerful than Earth’s. Its magnetosphere is so large, it clashes with the solar wind millions of miles before the wind even reaches the gas giant.
At the point where the supersonic solar wind collides with Jupiter’s magnetic field, the wind is rapidly heated and slowed, creating something called a bow shock, which astrophysicist William Kurth compares to a sonic boom. Kurth co-leads Juno’s Waves investigation, which just released a short video and eerie audio of the event.
“The solar wind blows past all the planets at a speed of about a million miles per hour, and where it hits an obstacle, there’s all this turbulence,” Kurth said in a press release. The obstacle — Jupiter’s magnetosphere — is the biggest single structure in our solar system. If we could see the structure with the naked eye, it would be twice the size of the moon, despite being hundreds of millions of miles further away.
The Waves chart and audio begins with the subtle plasma oscillations that Juno detected in the hour before encountering the bow shock. The drastic and dramatic change in frequency depicts the collision of two tremendous forces.