Juno, a spacecraft orbiting Jupiter, recently picked up an FM radio signal from one of Jupiter’s moons, Ganymede. (1) This is the first time this has ever happened and many people are wondering: Where could this radio signal possibly have come from?
Juno Detects FM Radio Signal From Jupiter’s Moon
Early this month, while Juno was making its regular orbit around Jupiter, one of the large planet’s moons, Ganymede, went flying past it. This time, however, was different than the usual rounds. Juno picked up something interesting from the moon: An FM radio signal. (1)
Naturally, many people’s first thoughts were that it could be a possible sign of alien life. NASA, however, was quick to overturn that idea. (1)
“It’s not E.T. It’s more of a natural function,” says Patrick Wiggins, one of NASA’s Ambassadors to Utah. (1)
You see, radio waves are not a human-made thing but more of a natural phenomenon that we have learned to use. At the time of detection, Juno was traveling across the polar region of Jupiter. In this region, there are magnetic field lines that connect to Ganymede. This is where Juno came in contact with the source of the FM radio waves, scientifically known as “decametric radio emission,”… aka Wi-Fi. (1)
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Jupiter and Its Radio Waves
While this is the first FM radio wave to be detected from Ganymede, scientists have known Jupiter to be a radiation source since 1955. In fact, Jupiter was the first planet that they ever detected radio waves from. This was also the first evidence of the Jovian magnetic field, aka Jupiter’s magnetic field. (2)
What Caused the FM Radio Signal
Again, not aliens, but electrons. Electrons oscillate (sway back and forth) slower than they spin. This makes the electrons amplify the radio waves at an extremely fast rate. This is known as cyclotron maser instability or CMI. (1)
Unfortunately, Juno was only able to pick up about five seconds worth of the radio waves. This is because Ganymede quite literally whips its way around Jupiter, at a rate of 50km per second, or 111,847 mph. For perspective, that’s fast enough to travel across the entirety of the United States – from one coast to the other – in under two minutes. (3)
Why Is This FM Radio Signal Important?
Just because it is not a sign of extraterrestrial life doesn’t mean that it isn’t significant. Spacecraft Juno’s mission is to discover how Jupiter was created and subsequently how it evolved. (1)
“Juno will observe Jupiter’s gravity and magnetic fields, atmospheric dynamics and composition, and evolution,” says NASA. (1)
Every discovery is another clue to solving that mystery. The more we understand the other planets in our galaxy and our solar system as a whole, the more we will understand our own planet.
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References
- “Discovery in space: FM radio signal coming from Jupiter’s moon Ganymede.” WBTW. January 15, 2021.
- “Radio emission.” Britannica.
- “FM radio signal found coming from Jupiter moon.” The Telegraph. January 13, 2021.